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POWER MANAGEMENT USB Power Switch
IMP252 4/27
Quad USB High-Side Power Switch with Fault Detection
IMP2525
USB High-Side Power Switch
IMP2525A
Low-Resistance, USB High-Side Power Switch
IMP2526
Dual USB High-Side Power Switch
408-432-9100/www.impweb.com
U S B Po w e r S w i t c h P r o d u c t G u i d e
Product Selection Guide
Part Number
IMP2524-1BWM IMP2524-2BWM IMP2524-1BN IMP2524-2BN IMP2525A-1BM IMP2525A-2BM IMP2525A-1BN IMP2525A-2BN IMP2525-1BM IMP2525-2BM IMP2525-1BN IMP2525-2BN IMP2526-1BM IMP2526-2BM IMP2526-1BN IMP2526-2BN IMP2527-1BWM IMP2527-2BWM IMP2527-1BN IMP2527-2BN
Type
Quad Quad Quad Quad Single Single Single Single Single Single Single Single Dual Dual Dual Dual Quad Quad Quad Quad
Package
16-pin, SO 16-pin, SO 16-pin, DIP 16-pin, DIP 8-pin, SO 8-pin, SO 8-pin, DIP 8-pin, DIP 8-pin, SO 8-pin, SO 8-pin, DIP 8-pin, DIP 8-pin, SO 8-pin, SO 8-pin, DIP 8-pin, DIP 16-pin, SO 16-pin, SO 16-pin, DIP 16-pin, DIP
Switch "ON" Resistance
0.14 0.14 0.14 0.14 0.070 0.070 0.070 0.070 0.14 0.14 0.14 0.14 0.14 0.14 0.14 0.14 0.30 0.30 0.30 0.30
Enable Logic
HIGH LOW HIGH LOW HIGH LOW HIGH LOW HIGH LOW HIGH LOW HIGH LOW HIGH LOW HIGH LOW HIGH LOW
Undervoltage Lockout
Current Limit
Thermal Shutdown
Fault Flag
* * * * * * * * * * * * * * * * * * * *
* * * * * * * * * * * * * * * * * * * *
* * * * * * * * * * * * * * * * * * * *
* * * * * * * * * * * * * * * * * * * *
USBSEL01
All devices are pin-compatible with the MIC2525/2526 devices. Compared to the Micrel MIC2525, the enhanced IMP2525A has a 50% lower "ON" resistance.
Product Cross Reference Guide
Micrel Part Number
MIC2524-1BWM MIC2524-2BWM MIC2524-1BN MIC2524-2BN MIC2525A-1BM MIC2525A-2BM MIC2525A-1BN MIC2525A-2BN MIC2525-1BM MIC2525-2BM MIC2525-1BN MIC2525-2BN MIC2526-1BM MIC2526-2BM MIC2526-1BN MIC2526-2BN MIC2527-1BWM MIC2527-2BWM MIC2527-1BN MIC2527-2BN
IMP Part Number
IMP2524-1BWM IMP2524-2BWM IMP2524-1BN IMP2524-2BN IMP2525A-1BM IMP2525A-2BM IMP2525A-1BN IMP2525A-2BN IMP2525-1BM IMP2525-2BM IMP2525-1BN IMP2525-2BN IMP2526-1BM IMP2526-2BM IMP2526-1BN IMP2526-2BN IMP2527-1BWM IMP2527-2BWM IMP2527-1BN IMP2527-2BN
Type
Quad Quad Quad Quad Single Single Single Single Single Single Single Single Dual Dual Dual Dual Quad Quad Quad Quad
Package
16-pin, SO 16-pin, SO 16-pin, DIP 16-pin, DIP 8-pin, SO 8-pin, SO 8-pin, DIP 8-pin, DIP 8-pin, SO 8-pin, SO 8-pin, DIP 8-pin, DIP 8-pin, SO 8-pin, SO 8-pin, DIP 8-pin, DIP 16-pin, SO 16-pin, SO 16-pin, DIP 16-pin, DIP
Switch "ON" Resistance
0.14 0.14 0.14 0.14 0.070 vs. 0.14 for Micrel 2525 0.070 vs. 0.14 for Micrel 2525 0.070 vs. 0.14 for Micrel 2525 0.070 vs. 0.14 for Micrel 2525 0.14 0.14 0.14 0.14 0.14 0.14 0.14 0.14 0.30 0.30 0.30 0.30
USBXref02
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(c) 2000 IMP, Inc.
IMP252 4/2 7
POWER MANAGEMENT ADVANCE PRODUCT INFORMATION Key Features
N N N N N N N N N USB Rev. 1.1 and 2.0 Compliant Four independent switches 2.7V to 5.5V input operation Low MOSFET ON resistance - IMP2524: 0.1, 0.14 maximum - IMP2527: 0.2, 0.3 maximum 500mA continuos load current per switch Low supply current - 110A ON-state current, 0.75A OFF-state current 1.25A maximum current limit, 750mA typical Thermal shutdown 2.4V undervoltage lockout (UVLO) Open-drain flag output - Undervoltage - Current limit - Thermal shutdown Output can be force higher than input Active HIGH(-1) and active LOW(-2) enable 16-pin SO and DIP packages, Die available Pin compatible with the Micrel MIC2524 and MIC2527
Quad USB High-Side Power Switch with Fault Detection
The IMP2524 and IMP2527 are complete power management solutions for bus-powered and self-powered USB hubs. Each device contains four independent power switches and fault detection logic. The IMP2524 channel resistance is a low 140m maximum and the IMP2527 channel resistance is 300 maximum. Both device operate with voltage inputs from 2.7V to 5.5V The IMP2524/2527 conform to the new USB 1.1 standard. Fault current is limited to 750mA typically, and a flag output for each switch conveys fault information to the local USB controller. The IMP252x "Soft-Start" function ramps the ON-current to eliminate any excessive voltage drop on the input side that could occur when capacitive loads are charged. Self-monitoring features include thermal shutdown to prevent catastrophic switch failure from high-current loads and undervoltage lockout (UVLO) that insures that the device remains OFF unless there is sufficient supply voltage present. The switch Enable input logic can interface with both 3.3V and 5V logic. Both active-HIGH (-1 devices) and active-LOW (-2 devices) enable logic versions are available. Supply current is a low 0.75A when disabled and just 110A when enabled The quad IMP2524/7 devices are available in 16-pin DIP and 16-pin SO packages and are pin compatible replacements for the Micrel MIC2524-1/-2 and MIC2527-1/2 devices. IMP offers a complete family of USB power management products. For single-switch applications see the IMP2525 and IMP2525A data sheets. The single-switch IMP2525A features a 0.07 switch resistance. For dual-switch applications, refer to the IMP2526 data sheet.
N N N N
Applications
N USB host and self-powered hubs N USB video monitors N USB printers
VBUS
Typical Application
IMP2527 5.1V 3% 5V 1% or IMP2524 5V 3% 4.7mF Ferrite Bead 10k
27k 2 1 3 4 5 6
IMP2524 IMP2527 ENA ENB INA/B OUTA 16 15 14 13 12 11 10 9
33mF*
+
D+ 0.01mF D- GND
+
IN OUT LDO GND
V+
ON/OFF
OVERCURRENT USB Controller D+ D- 1mF GND
FLGA INC/D FLGB OUTB ENC OUTC FLGC OUTD END FLGD GND GND
Downstream USB Port 1 500mA max.
0.1mF 33mF*
VBUS
+
D+ 0.01mF D- GND VBUS
Data
7 8
Downstream USB Port 2 500mA max.
33mF* Bold/Blue lines indicate 0.1" wide, 1-oz. copper high-current traces. *33mF, 16V tantalum or 100mF, 10V electrolytic per port
+
D+ 0.01mF D- GND VBUS
Downstream USB Port 3 500mA max.
33mF*
+
D+ 0.01mF D- GND
Downstream USB Port 4 500mA max.
2524/27_01.eps
(c) 2000 IMP, Inc.
408-432-9100/www.impweb.com
1
IMP2524/27
Pin Configuration
SO/DIP
FLGA ENA OUTA GND INC/D OUTC ENC FLGC 1 2 3 4 5 6 7 8 IMP2524/27 16 FLGB 15 ENB 14 OUTB 13 INA/B 12 GND 11 OUTD 10 END 9 FLGD
2524/27_02.eps
FLGA ENA FLGB ENB
1 2 16 15
3 Logic, Charge Pump Logic, Charge Pump IMP2524/27
OUTA
13
INA/B
14 6
OUTB OUTC
ENC FLGC FLGD END
7 8 9 10
Logic, Charge Pump Logic, Charge Pump 4 GND 12 GND
5
INC/D
11
OUTD
Pin Descriptions
Pin Number
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
2524/27_03.eps
Name
FLGA ENA OUTA GND INC/D OUTC ENC FLGC FLGD END OUTD GND INA/B OUTB ENB FLGB
Function
Fault Flag A output. This open-drain output goes into an active-LOW state in response to undervoltage, current limit or thermal shutdown conditions. Enable A Input. This pin is the Channel B MOSFET switch driver control logic input. Both active-HIGH (-1 suffix) and active-LOW (-2 suffix) logic devices are available. Channel-A switch output (MOSFET Source). The output pin drives the load into ON and OFF states. Ground. Power supply return for the internal circuitry of the IC. Connect both pins 4 and 6 together. Channel C and D positive power supply input voltage. This is the switching MOSFET drain connection. It is the channel C and channel D supply voltage input for the logic and the charge-pump circuit. Channel-C switch output (MOSFET Source). The output pin drives the load into ON and OFF states. Enable C Input. This pin is the Channel B MOSFET switch driver control logic input. Both active-HIGH (-1 suffix) and active-LOW (-2 suffix) logic devices are available. Fault Flag C output. This open-drain output goes into an active-LOW state in response to undervoltage, current limit or thermal shutdown conditions. Fault Flag D output. This open-drain output goes into an active-LOW state in response to undervoltage, current limit or thermal shutdown conditions. Enable D Input. This pin is the Channel B MOSFET switch driver control logic input. Both active-HIGH (-1 suffix) and active-LOW (-2 suffix) logic devices are available. Channel-D switch output (MOSFET Source). The output pin drives the load into ON and OFF states. Ground. Power supply return for the internal circuitry of the IC. Connect both pins 4 and 6 together. Channel A and B positive power supply input voltage. This is the switching MOSFET drain connection. It is the channel A and channel B supply voltage input for the logic and the charge-pump circuit. Channel-B switch output (MOSFET Source). The output pin drives the load into ON and OFF states. Enable B Input. This pin is the Channel-B MOSFET switch driver control logic input. Both active-HIGH (-1 suffix) and active-LOW (-2 suffix) logic devices are available. Fault Flag B output. This open-drain output goes into an active-LOW state in response to undervoltage, current limit or thermal shutdown conditions.
2524/27t01
Ordering Information
Pin Number
IMP2524-1BWM IMP2524-2BWM IMP2524-1BN IMP2524-2BN IMP2527-1BWM IMP2527-2BWM IMP2527-1BN IMP2527-2BN
Enable Logic
Active HIGH Active LOW Active HIGH Active LOW Active HIGH Active LOW Active HIGH Active LOW
Typical "ON" Resistance
100m 100m 100m 100m 200m 200m 200m 200m
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Temperature Range
-40 -40 -40 -40 -40 -40 -40 -40 C to +85 C to +85 C to +85 C to +85 C to +85 C to +85 C to +85 C to +85 C C C C C C C C
Pins-Package
16-SO 16-SO 16-DIP 16-DIP 16-SO 16-SO 16-DIP 16-DIP
2524/27t02
2
(c) 2000 IMP, Inc.
IMP2524/27
Absolute Maximum Ratings
Supply Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . +8.0V Fault Flag Voltage . . . . . . . . . . . . . . . . . . . . . . +8.0V Fault Flag Current . . . . . . . . . . . . . . . . . . . . . . 50mA Output Voltage . . . . . . . . . . . . . . . . . . . . . . . . . +8.0V Output Current . . . . . . . . . . . . . . . . . . . . . . . . . Internally Limited Enable Input . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3V to 12V Storage Temperature . . . . . . . . . . . . . . . . . . . . . -65C to +150C Lead Temperature (Soldering, 5 sec.) . . . . . . . 260C Package Thermal Resistance SO (JA ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160C/W DIP(JA ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130C/W Note: All voltages are referenced to GND. These are stress ratings only and functional operation is not implied. Exposure to absolute maximum ratings for prolonged time periods may affect device reliability.
Electrical Characteristics
Unless otherwise noted, VIN = 5V and TA = 25C.
Parameter
Supply Voltage Range Operating Temperature Range Supply Current Switch OFF Supply Current Switch ON Enable Input Threshold Enable Input Current Enable Input Capacitance Switch ON Resistance Continuous Load Current Output Turn-On Delay Output Turn-On Rise Time Output Turn-Off Delay Output Turn-Off Fall Time Output Leakage Current Short-circuit Current Limit Overtemperature Shutdown Threshold Error Flag Output Resistance Error Flag Output Current UVLO Threshold
Symbol Conditions
VIN TA IIN OFF Switch OFF, No load VENOFF 0.8V, VENON 2.4V IMP2524/27-1 VENON 0.8V, VENOFF 2.4V IMP2524/27-2 Switch ON, No load VENOFF 0.8V, VENON 2.4V IMP2524/27-1 VENON 0.8V, VENOFF 2.4V IMP2524/27-2 LOW to HIGH ("0" to "1") Enable Voltage, Note 1 HIGH to LOW ("1" to "0") Enable Voltage, Note 1 VEN = 2.4V VEN = 0.8V CEN RON IL TDON TRON TDOFF TFOFF IOFF ISC TJ increasing TJ decreasing RFLAG IFLAG VUVLO VIN = 5V, IL = 10mA VIN = 3.3V, IL = 10mA VFLAG = 5V VIN Increasing VIN Decreasing IMP2524: IOUT = 500mA each switch IMP2527: IOUT = 500mA each switch Each output RL = 10 each output RL = 10 each output RL = 10 each output RL = 10 each output TA = - 40C to +85C
Min
2.7 - 40
Typ
Max
5.5 85
Units
V C A
0.75
10
IIN ON
110
320
A
VENH VENL IEN
2.1 0.8 1.9 0.01 0.01 1 0.10 0.20 0.5 0.25 1 1 1 0.50 0.75 135 125 10 15 0.01 2.5 2.3
2.4 1 1
V A pF
0.14 0.30
A ms ms
20 20 10 1.25
s s A A C
1
A V
Notes 1. Switch OFF is VEN 0.8V and Switch ON is VEN 2.4V for the IMP2524/27-1. Switch OFF is VEN 2.4V and Switch ON is VEN 0.8V for the IMP2524/27-2. The Enable input has approximately 200mV of hysteresis.
(c) 2000 IMP, Inc.
USB High-Side Power Switches
3
IMP2524/27
Package Dimensions
Plastic DIP (16-Pin)
D1
N
Inches Min Max
0.200 ---- -- 0.175 0.022 0.065 0.012 0.765 0.080 0.325 0.310 ---- -- ---- -- 0.400 0.150
Millimeters Min
---- -- 0.38 3.18 0.41 1.14 0.20 18.92 0.13 7.62 6.10 2.54 7.62 ---- -- 2.92
Max
5.08 ---- -- 4.45 0.56 1.65 0.30 19.43 2.03 8.26 7.87 ---- -- ---- -- 10.16 3.81
Plastic DIP (16-Pin)*
E1 E
D A2 A
A1 L e B B1
0-15 C eA eB
Plastic DIP (16-Pin).eps
SO (16-Pin)
A A1 A2 B B1 C D D1 E E1 e eA eB L
---- -- 0.015 0.125 0.016 0.045 0.008 0.745 0.005 0.300 0.240 0.100 0.300 ---- -- 0.115
SO (16-Pin)**
A 0.926 0.1043 A1 0.0040 0.0118 B 0.013 0.020 C 0.0091 0.0125 D 0.3977 0.4133 E 0.2914 0.2662 e 0.050 BSC H 0.394 0.419 L 0.016 0.050 * JEDEC Drawing MO-058AB ** JEDEC Drawing MS-013AA 2.35 2.65 0.10 0.30 0.33 0.51 0.23 0.32 10.10 10.50 7.40 7.60 1.27 BSC 10.00 10.65 0.40 1.27
2524/26_t03.at3
E
H
D 0- 8 A C e B A1 L
16-Pin (SO).eps
4
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(c) 2000 IMP, Inc.
IMP2525
POWER MANAGEMENT
USB High-Side Power Switch
- Single switch - 0.14 "ON" resistance at 3V - MIC2525 pin compatible
Key Features
N Meets or exceeds USB Rev. 1.1 and 2.0 specification N Low MOSFET RON (0.14 at 3V) N 2.7V to 5.5V input operation N Current limiting N Soft-start turn-on (1ms) prevents turn-on glitches N 500mA continuous load current N MOSFET short-circuit current limit (1.25A max) N Low supply current - 110A ON state current, 1A OFF state current N Active-LOW or Active-HIGH Enable input N 3.3V or 5V logic compatibility N Fault Flag indicates three fault conditions: - Undervoltage - Current limit - Thermal shutdown N Open-drain Fault Flag output N 2.4V Undervoltage Lockout (UVLO) N Pin compatible with the Micrel MIC2525
The IMP2525 high-side power switch IC is designed for self-powered and bus-powered Universal Serial Bus (USB) power supply and power management applications. The IMP2525 conforms to USB standards with a low output switch ON-resistance (RON) and minimal voltage drop across the switch. The fault current is limited to 750mA typically, and a flag output conveys fault conditions to the local USB controller. The IMP2525 provides a "Soft-Start" function that ramps up the ONcurrent to eliminate any excessive voltage drop on the input side that could occur due to charging a capacitive load in bus-powered applications. Self-monitoring features include thermal shutdown to prevent catastrophic switch failure from high-current loads and undervoltage lockout (UVLO) that insures that the device remains off unless there is a valid supply voltage present. The Enable input logic can be interfaced with both 3.3V and 5V logic. Both active-HIGH and active-LOW enable logic versions are available. The IMP2525 devices are available in 8-pin DIP and 8-pin SO packages. IMP offers a complete family of USB power management products. For dual-switch applications see the IMP2526 data sheet and for quad-switch application, see the IMP2524. The single-switch IMP2525A features a 50% lower switch resistance, 0.07.
Applications
N USB power management N USB hosts and self-powered hubs N Battery-charger circuits and power supplies
8
Block Diagrams
IN EN
7 1 1.2V Reference Current Limit UVLO Power Switch Gate Control
OUT NC/OUT
6
Thermal Shutdown
2
FLG
Oscillator
Charge Pump
3
GND
IMP2525
2525_01.eps
(c) 2000 IMP, Inc.
408-432-9100/www.impweb.com
1
IMP2525
Pin Configuration
SO/DIP
8 EN FLG GND NC 1 2 3 4 IMP2525 8 7 6 5 OUT IN NC/OUT NC 3 GND
2525_03.eps
*
EN FLG
1 2 Logic, Charge Pump 6 7
OUT
IN
*Connect pins 6 and 8 for MIC2525 compatibility
2525_02.eps
Pin Descriptions
Pin Number
1 2 3 4, 5 6 7 8
Name
EN FLG GND NC NC/OUT IN OUT
Function
Enable input. This pin is the MOSFET switch driver logic input. Both active-HIGH (-1 suffix) and active-LOW (-2 suffix) logic devices are available. Fault flag output. This open-drain output goes into an active-LOW state in response to undervoltage, current limit or thermal shutdown conditions. Ground. Power supply return for the internal circuitry of the IC. No connection. These pins have no internal connections to the device. No connection. This pin has no internal connection to the device. Connect pins 6 and 8 to maintain pin-compatibility with the MIC2525. Positive power supply voltage input. This is the switching MOSFET drain connection as well as the positive supply for the IC. MOSFET source. The output pin supplies power to the load.
Ordering Information
Part Number
IMP2525-1BM IMP2525-2BM IMP2525-1BN IMP2525-2BN
Enable Logic
Active HIGH Active LOW Active HIGH Active LOW
Temperature Range
- 40C to +85C - 40C to +85C - 40C to +85C - 40C to +85C
Pins-Package
8-SO 8-SO 8-DIP 8-DIP
2
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(c) 2000 IMP, Inc.
IMP2525
Absolute Maximum Ratings
Supply Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . +6.0V Fault Flag Voltage . . . . . . . . . . . . . . . . . . . . . . +6.0V Fault Flag Current . . . . . . . . . . . . . . . . . . . . . . 50mA Output Voltage . . . . . . . . . . . . . . . . . . . . . . . . . +6.0V Output Current . . . . . . . . . . . . . . . . . . . . . . . . . Internally Limited Enable Input . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3V to 12V Storage Temperature . . . . . . . . . . . . . . . . . . . . . -65C to +150C Lead Temperature (Soldering, 5 sec.) . . . . . . . 260C Package Thermal Resistance SO (JA) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120C/W DIP(JA) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130C/W Note: All voltages are referenced to GND. These are stress ratings only and functional operation is not implied. Exposure to absolute maximum ratings for prolonged time periods may affect device reliability.
Electrical Characteristics
Unless otherwise noted, VIN = 5V and TA = 25C.
Parameter
Supply Voltage Range Operating Temperature Range Supply Current Switch OFF Supply Current Switch ON Enable Input Threshold Enable Input Current Enable Input Capacitance Switch ON Resistance Output Turn-On Delay Output Turn-On Rise Time Output Turn-Off Delay Output Turn-Off Fall Time Output Leakage Current Short-circuit Current Limit Overtemperature Shutdown Threshold Error Flag Output Resistance Error Flag Output Current UVLO Threshold
Symbol Conditions
VIN TA IIN OFF Switch OFF, No load VENOFF 0.8V, VENON 2.4V IMP2525-1 VENON 0.8V, VENOFF 2.4V IMP2525-2 Switch ON, No load VENOFF 0.8V, VENON 2.4V IMP2525-1 VENON 0.8V, VENOFF 2.4V IMP2525-2 LOW to HIGH ("0" to "1") Enable Voltage, Note 1, 2 HIGH to LOW ("1" to "0") Enable Voltage, Note 1, 2 VEN = 0V to 5.5V VIN = 5V, IOUT = 500mA VIN = 3.3V, IOUT = 500mA TDON TRON TDOFF TFOFF IOFF ISC TJ increasing TJ decreasing RFLAG IFLAG VUVLO VIN = 5V, IL = 10mA VIN = 3.3V, IL = 10mA VFLAG = 5V VIN Increasing VIN Decreasing RL = 10 RL = 10 RL = 10, Note 2 RL = 10, Note 2 TA = - 40C to +85C
Min
2.7 - 40
Typ
Max
5.5 85
Units
V C A
0.75
5
IIN ON
110
160
A
VENH VENL IEN CEN RON
2.1 0.8 -1 1.9 0.01 1 0.1 0.14 0.25 1 1 1 0.50 0.75 135 125 10 15 0.01 2.5 2.3
2.4 1 0.14 0.18
V A pF ms ms
20 20 10 1.25
s s A A C
25 40 1
A V
Notes 1. Switch OFF is VEN 0.8V and Switch ON is VEN 2.4V for the IMP2525-1. Switch OFF is VEN 2.4V and Switch ON is VEN 0.8V for the IMP2525-2. The Enable input has approximately 200mV of hysteresis. 2. Over operating temperature range, -40C TA 85C.
(c) 2000 IMP, Inc.
USB High-Side Power Switches
3
IMP2525
Detailed Descriptions
The IMP2525 is a high-side N-channel MOSFET switch that interfaces with a USB controller by means of a Switch-Enable input and a Fault-Flag output. The Enable input turns ON the power MOSFET with either a logic "1" for the IMP2525-1 or logic "0" for the IMP2525-2. Any one of three fault conditions will activate the open-drain Fault-Flag Output to alert the controller that the power MOSFET has been turned OFF.
Thermal Shutdown
Thermal shutdown is active when the output switch is enabled (turned ON). Thermal shutdown shuts off the output MOSFET and sets the Fault Flag if the on-chip temperature sensor exceeds 135C. The switch is held OFF until the die temperature drops to 125C or below. This 10C of hysteresis will result in ON-OFF short-circuit cycling if the short-circuit condition is not removed or the bus-controller does turn off the switch with the Enable input. Over temperature detection is active only if the chip is enabled.
Input and Output
The IN (input) pin is the power supply connection to the logic circuitry and the "High-Side" of the switch (the Drain of the power MOSFET). The OUT (output) pin is the "Low-Side" of the switch (the Source of the power MOSFET). In a typical circuit, current flows through the switch from IN to OUT toward the load. The switch is referred to as a "High-Side" switch since it drives the positive (or high) side of the load. The output MOSFET source can be forced to a higher voltage than the drain (VOUT > VIN) when the output is OFF with little leakage current. If, however, VIN drops below 2.3V, reverse current may flow out the IN pin regardless of the enable state. When the power switch is ON, current can flow in either direction.
Undervoltage Lockout
The Undervoltage lockout (UVLO) prevents the output MOSFET from being put into the ON state until the positive supply voltage, VIN, exceeds 2.5V. When the output switch is in the ON state and the positive supply voltage drops below 2.3V, the UVLO circuitry will assert the Fault Flag, FLG, and shut OFF the output MOSFET. The FLG output will only assert an active LOW state when the MOSFET switch is in the ON state. Undervoltage detection is active only if the chip is enabled.
Current Limiting
Current limiting is achieved by sensing the voltage drop from Drain-to-Source of the power MOSFET. When the internal threshold is exceeded the power MOSFET is turned OFF.
Fault Flag - FLG Pin
The Fault Flag pin, FLG, connects to an N-channel, open-drain MOSFET and goes LOW ("0") for an occurrence of one or more of three conditions: undervoltage, current limit, or thermal shutdown. The FLG output MOSFET is capable of sinking a 10mA load to typically 100mV above ground. Table 1 gives the states of the FLG and OUT pins when a fault condition is detected.
Table 1. Fault Flag Conditions - Switch Enabled
Condition
Thermal Shutdown Undervoltage Lockout (UVLO) Current Limiting
Cause
TJ > 135C VIN < 2.3V IO > 0.5A (step load) IO > 0.63A (ramped load)
FLG pin "0" Until
TJ 125C VIN > 2.5V Enable off or Thermal Shutdown
Switch State (FLG = "0")
Turns OFF Turns OFF Stays ON
4
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IMP2525
Application Information
Supply Filtering
IMP strongly recommends the use of a 0.1F to 1F bypass capacitor to control transients on the power supply pin. This capacitor, connected from IN to GND, should be in close proximity to the IMP2525 for maximum transient suppression. The lack of suitable bypassing can result in ringing on the IN input when transients occur. This ringing, due to supply lead inductance, could damage IMP2525 control circuitry if the 8V maximum input rating is exceeded.
4.0V to 5.5V
Enable Input
As with any logic input, the enable pin, EN, must be driven to a definitive logic state at all times. Floating the input can result in spurious operation. Do not drive EN below GND.
Fault Flag Output Soft Start
The IMP2525 provides a "Soft-Start" function that ramps up the ON-current to eliminate any excessive voltage drop that could occur due to charging a capacitive load in bus-powered applications. The "Soft-Start" results from a switch ON resistance, RON, that is ramped down from a high impedance to 0.14 in milliseconds. This RON ramping reduces the inrush current and related transients occur when charging capacitive loads; a requirement for meeting the USB voltage drop standards for bus-powered applications (see Figure 2). In circuits with large load capacitances, CBULK, exceeding 10F, the soft-start circuit shown in Figure 3 can be used to limit the inrush start-up current to USB transient specifications. The current limiting feature of the IMP2525 provides this high-load, soft-start operation.
IMP2525 IN 3 GND
7
0.1F to 1F
2525_04.eps
Figure 1. Supply Bypassing
USB Controller IMP2525-xBM VBUS 1 2 3 USB Host 4.7F GND Cable Bus Powered Hub Cable Downstream USB Device
2525_06.eps
EN FLG GND
OUT IN OUT
8 7 6 Capacitive Load 0.1F CBULK
4 NC
NC 5
Figure 2. Soft-Start Application
(c) 2000 IMP, Inc.
USB High-Side Power Switches
5
IMP2525
Application Information
IMP2525-2 VBUS 1 EN OUT IN OUT 8 7 6
USB Controller
2 FLG 3 USB Hub 4.7F GND Cable GND
USB Function
4 NC
NC 5 CBULK
USB Peripheral
2525_07.eps
Figure 3. Inrush Current-Limit Application
Transient Overcurrent Filter
If a heavy capacitive load is suddenly connected to the output, the switch current-limiting function may cause the fault-flag to go low for 10s to 200s as the switch, in a constant current mode, charges the capacitance. If this transient over-current fault reporting is not wanted, a simple 1ms RC low-pass filter in series with the fault flag circuit will prevent this momentary flag (Figure 4).
USB Controller OVERCURRENT 10k 10k
V+
2
IMP2525 FLG
0.1F
2525_05.eps
Figure 4. Transient Filter
VCC 5.0V Upstream VBUS 100mA max VBUS D+ LDO D- GND GND 1F 1F GND GND 3 0.1F GND IN OUT VIN 10k 100k Ferrite Beads 8 VBUS D+ USB Port
ON/OFF
1 2
EN
OUT
OVERCURRENT 3.3V USB Controller
7 FLG IN IMP2525-2 6 OUT 150F
+
D-
2525_08.eps
Data
Data
Figure 5. Single-Port Self-Powered Hub Application
6
408-432-9100/www.impweb.com (c) 2000 IMP, Inc.
IMP2525
Package Dimensions
Plastic DIP (8-Pin)
D1
Inches Min
A A1
E
Millimeters Max Min Max Plastic DIP (8-Pin)*
0.210 ----- 0.195 0.022 0.070 0.045 0.400 ----- 0.325 0.280 ----- ----- 0.430 0.060 0.150 0.069 0.010 0.020 0.010 2.92 1.35 0.10 0.33 0.19 1.27 0.157 0.244 0.050 0.197 3.80 5.80 0.40 4.80 4.00 6.20 1.27 5.00 3.81 1.75 0.25 0.51 0.25 ----- ---- 0.38 2.92 0.36 1.14 0.80 9.02 0.13 7.62 6.10 2.54 7.62 10.92 5.33 ----- 4.95 0.56 1.78 1.14 10.16 ----- 8.26 7.11
----- 0.015 0.115 0.014 0.045 0.030 0.355 0.005 0.300 0.240 0.100 0.300 ----- ----- 0.115 0.053 0.004 0.013 0.007 0.050 0.150 0.228 0.016 0.189
D A A2
A2 b b2 b3
E1
L A1 e b b2
0-15 C eA eB
Plastic DIP (8-Pin)a.eps
D D1 E E1 e eA
SO (8-Pin)
0- 8
eB eC
L
L A A1 B C
SO (8-Pin)**
E H
C D A
e E H L D
e B A1
SO (8-Pin).eps
* JEDEC Drawing MS-001BA ** JEDEC Drawing MS-012AA
(c) 2000 IMP, Inc.
USB High-Side Power Switches
7
Notes
Project
8
408-432-9100/www.impweb.com
(c) 2000 IMP, Inc.
IMP2525A
POWER MANAGEMENT
Low-Resistance USB High-Side Power Switch
Key Features
N Meets or exceeds USB Rev. 1.1 and 2.0 specification N Low MOSFET RON (0.07 at 3V) N Pin compatible with the Micrel MIC2525 - 50% lower than MIC2525 N 2.7V to 5.5V input operation N Current limiting N Soft-start turn-on (1ms) prevents turn-on glitches N 500mA continuous load current N MOSFET short-circuit current limit (2.5A max) N Low supply current - 110A ON state current, 1A OFF state current N Active-LOW or Active-HIGH Enable input N 3.3V or 5V logic compatibility N Open-drain Fault Flag indicates three fault conditions: - Undervoltage - Current limit - Thermal shutdown N 2.4V Undervoltage Lockout (UVLO)
- Single switch - 0.07 "ON" resistance at 3V - 50% lower resistance than MIC2525 - MIC2525 pin compatible
The IMP2525A high-side power switch IC is designed for self-powered and bus-powered Universal Serial Bus (USB) power supply and power management applications. The IMP2525A conforms to USB standards with a low output switch ON-resistance (RON) and minimal voltage drop across the switch. Switch resistance is 50% lower than the MIC2525. The fault current is limited to 1.5A typically, and a flag output conveys fault conditions to the local USB controller. The IMP2525A provides a "Soft-Start" function that ramps up the ON-current to eliminate any excessive voltage drop on the input side that could occur due to charging a capacitive load in bus-powered applications. Self-monitoring features include thermal shutdown to prevent catastrophic switch failure from high-current loads and undervoltage lockout (UVLO) that insures that the device remains off unless there is a valid supply voltage present. The Enable input logic can be interfaced with both 3.3V and 5V logic. Both active-HIGH and active-LOW enable logic versions are available. The IMP2525A devices are available in 8-pin DIP and 8-pin SO packages. IMP offers a complete family of USB power management products. For dual-switch applications see the IMP2526 data sheet and for quad-switch application, see the IMP2524. The single-switch IMP2525 matches the performance of the Micrel MIC2525.
Applications
N USB power management N USB hosts and self-powered hubs N Battery-charger circuits and power supplies
Block Diagrams
IN EN 7 1 1.2V Reference 50% Lower Resistance Than MIC2525
8
OUT OUT
Current Limit
6 Power Switch Gate Control 2
UVLO
Thermal Shutdown Charge Pump 3
FLG
Oscillator
GND
IMP2525A
2525A_01.eps
(c) 2000 IMP, Inc.
408-432-9100/www.impweb.com
1
IMP2525A
Pin Configuration
SO/DIP
8 EN FLG GND NC 1 2 3 4 IMP2525A 8 7 6 5 OUT IN OUT NC 3
2525A_02.eps
EN FLG
1 2 Logic, Charge Pump 6 7
OUT
IN
GND
2525A_03.eps
Pin Descriptions
Pin Number
1 2 3 4, 5 6 7 8
Name
EN FLG GND NC OUT IN OUT
Function
Enable input. This pin is the MOSFET switch driver logic input. Both active-HIGH (-1 suffix) and active-LOW (-2 suffix) logic devices are available. Fault flag output. This open-drain output goes into an active-LOW state in response to undervoltage, current limit or thermal shutdown conditions. Ground. Power supply return for the internal circuitry of the IC. No connection. These pins have no internal connections to the device. MOSFET source. The output pin supplies power to the load. Positive power supply voltage input. This is the switching MOSFET drain connection as well as the positive supply for the IC. MOSFET source. The output pin supplies power to the load.
Ordering Information
Part Number
IMP2525A-1BM IMP2525A-2BM IMP2525A-1BN IMP2525A-2BN
Enable Logic
Active HIGH Active LOW Active HIGH Active LOW
Temperature Range
- 40C to +85C - 40C to +85C - 40C to +85C - 40C to +85C
Pins-Package
8-SO 8-SO 8-DIP 8-DIP
2
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(c) 2000 IMP, Inc.
IMP2525A
Absolute Maximum Ratings
Supply Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . +6.0V Fault Flag Voltage . . . . . . . . . . . . . . . . . . . . . . +6.0V Fault Flag Current . . . . . . . . . . . . . . . . . . . . . . 50mA Output Voltage . . . . . . . . . . . . . . . . . . . . . . . . . +6.0V Output Current . . . . . . . . . . . . . . . . . . . . . . . . . Internally Limited Enable Input . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3V to 12V Storage Temperature . . . . . . . . . . . . . . . . . . . . . -65C to +150C Lead Temperature (Soldering, 5 sec.) . . . . . . . 260C Package Thermal Resistance SO (JA) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120C/W DIP(JA) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130C/W Note: All voltages are referenced to GND. These are stress ratings only and functional operation is not implied. Exposure to absolute maximum ratings for prolonged time periods may affect device reliability.
Electrical Characteristics
Unless otherwise noted, VIN = 5V and TA = 25C.
Parameter
Supply Voltage Range Operating Temperature Range Supply Current Switch OFF Supply Current Switch ON Enable Input Threshold Enable Input Current Enable Input Capacitance Switch ON Resistance Output Turn-On Delay Output Turn-On Rise Time Output Turn-Off Delay Output Turn-Off Fall Time Output Leakage Current Short-circuit Current Limit Overtemperature Shutdown Threshold Error Flag Output Resistance Error Flag Output Current UVLO Threshold
Symbol Conditions
VIN TA IIN OFF Switch OFF, No load VENOFF 0.8V, VENON 2.4V IMP2525A-1 VENON 0.8V, VENOFF 2.4V IMP2525A-2 Switch ON, No load VENOFF 0.8V, VENON 2.4V IMP2525A-1 VENON 0.8V, VENOFF 2.4V IMP2525A-2 LOW to HIGH ("0" to "1") Enable Voltage, Note 1, 2 HIGH to LOW ("1" to "0") Enable Voltage, Note 1, 2 VEN = 0V to 5.5V VIN = 5V, IOUT = 500mA VIN = 3.3V, IOUT = 500mA TDON TRON TDOFF TFOFF IOFF ISC TJ increasing TJ decreasing RFLAG IFLAG VUVLO VIN = 5V, IL = 10mA VIN = 3.3V, IL = 10mA VFLAG = 5V VIN Increasing VIN Decreasing RL = 10 RL = 10 RL = 10, Note 2 RL = 10, Note 2 TA = - 40C to +85C
Min
2.7 - 40
Typ
Max
5.5 85
Units
V C A
0.75
5
IIN ON
110
160
A
VENH VENL IEN CEN RON
2.1 0.8 -1 1.9 0.01 1 0.05 0.07 0.25 1 1 1 1.0 1.5 135 125 10 15 0.01 2.5 2.3
2.4 1 0.07 0.09
V A pF ms ms
20 20 10 2.5
s s A A C
25 40 1
A V
Notes 1. Switch OFF is VEN 0.8V and Switch ON is VEN 2.4V for the IMP2525A-1. Switch OFF is VEN 2.4V and Switch ON is VEN 0.8V for the IMP2525A-2. The Enable input has approximately 200mV of hysteresis. 2. Over operating temperature range, -40C TA 85C.
(c) 2000 IMP, Inc.
USB High-Side Power Switches
3
IMP2525A
Detailed Descriptions
The IMP2525A is a high-side N-channel MOSFET switch that interfaces with a USB controller by means of a Switch-Enable input and a Fault-Flag output. The Enable input turns ON the power MOSFET with either a logic "1" for the IMP2525-1 or logic "0" for the IMP2525-2. Any one of three fault conditions will activate the open-drain Fault-Flag Output to alert the controller that the power MOSFET has been turned OFF.
Thermal Shutdown
Thermal shutdown is active when the output switch is enabled (turned ON). Thermal shutdown shuts off the output MOSFET and sets the Fault Flag if the on-chip temperature sensor exceeds 135C. The switch is held OFF until the die temperature drops to 125C or below. This 10C of hysteresis will result in ON-OFF short-circuit cycling if the short-circuit condition is not removed or the bus-controller does turn off the switch with the Enable input. Over temperature detection is active only if the chip is enabled.
Input and Output
The IN (input) pin is the power supply connection to the logic circuitry and the "High-Side" of the switch (the Drain of the power MOSFET). The OUT (output) pin is the "Low-Side" of the switch (the Source of the power MOSFET). In a typical circuit, current flows through the switch from IN to OUT toward the load. The switch is referred to as a "High-Side" switch since it drives the positive (or high) side of the load. The output MOSFET source can be forced to a higher voltage than the drain (VOUT > VIN) when the output is OFF with little leakage current. If, however, VIN drops below 2.3V, reverse current may flow out the IN pin regardless of the enable state. When the power switch is ON, current can flow in either direction.
Undervoltage Lockout
The Undervoltage lockout (UVLO) prevents the output MOSFET from being put into the ON state until the positive supply voltage, VIN, exceeds 2.5V. When the output switch is in the ON state and the positive supply voltage drops below 2.3V, the UVLO circuitry will assert the Fault Flag, FLG, and shut OFF the output MOSFET. The FLG output will only assert an active LOW state when the MOSFET switch is in the ON state. Undervoltage detection is active only if the chip is enabled.
Current Limiting
Current limiting is achieved by sensing the voltage drop from Drain-to-Source of the power MOSFET. When the internal threshold is exceeded the power MOSFET is turned OFF.
Fault Flag - FLG Pin
The Fault Flag pin, FLG, connects to an N-channel, open-drain MOSFET and goes LOW ("0") for an occurrence of one or more of three conditions: undervoltage, current limit, or thermal shutdown. The FLG output MOSFET is capable of sinking a 10mA load to typically 100mV above ground. Table 1 gives the states of the FLG and OUT pins when a fault condition is detected.
Table 1. Fault Flag Conditions - Switch Enabled
Condition
Thermal Shutdown Undervoltage Lockout (UVLO) Current Limiting
Cause
TJ > 135C VIN < 2.3V IO > 1.0A (step load) IO > 1.25A (ramped load)
FLG pin "0" Until
TJ 125C VIN > 2.5V Enable off or Thermal Shutdown
Switch State (FLG = "0")
Turns OFF Turns OFF Stays ON
4
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(c) 2000 IMP, Inc.
IMP2525A
Application Information
Supply Filtering
IMP strongly recommends the use of a 0.1F to 1F bypass capacitor to control transients on the power supply pin. This capacitor, connected from IN to GND, should be in close proximity to the IMP2525A for maximum transient suppression. The lack of suitable bypassing can result in ringing on the IN input when transients occur. This ringing, due to supply lead inductance, could damage IMP2525A control circuitry if the 8V maximum input rating is exceeded.
4.0V to 5.5V
Enable Input
As with any logic input, the enable pin, EN, must be driven to a definitive logic state at all times. Floating the input can result in spurious operation. Do not drive EN below GND.
Fault Flag Output Soft Start
The IMP2525A provides a "Soft-Start" function that ramps up the ON-current to eliminate any excessive voltage drop that could occur due to charging a capacitive load in bus-powered applications. The "Soft-Start" results from a switch ON resistance, RON, that is ramped down from a high impedance to 0.07 in milliseconds. This RON ramping reduces the inrush current and related transients occur when charging capacitive loads; a requirement for meeting the USB voltage drop standards for bus-powered applications (see Figure 2). In circuits with large load capacitances, CBULK, exceeding 10F, the soft-start circuit shown in Figure 3 can be used to limit the inrush start-up current to USB transient specifications. The current limiting feature of the IMP2525A provides this high-load, soft-start operation.
IMP2525A IN 3 GND
7
0.1F to 1F
2525A_04.eps
Figure 1. Supply Bypassing
USB Controller IMP2525A-xBM VBUS 1 2 3 USB Host 4.7F GND Cable Bus Powered Hub Cable Downstream USB Device
2525A_06.eps
EN FLG GND
OUT IN OUT
8 7 6 Capacitive Load 0.1F CBULK
4 NC
NC 5
Figure 2. Soft-Start Application
(c) 2000 IMP, Inc.
USB High-Side Power Switches
5
IMP2525A
Application Information
IMP2525A-2 VBUS 1 EN OUT IN OUT 8 7 6
USB Controller
2 FLG 3 USB Hub 4.7F GND Cable GND
USB Function
4 NC
NC 5 CBULK
USB Peripheral
2525A_07.eps
Figure 3. Inrush Current-Limit Application
Transient Overcurrent Filter
If a heavy capacitive load is suddenly connected to the output, the switch current-limiting function may cause the fault-flag to go low for 10s to 200s as the switch, in a constant current mode, charges the capacitance. If this transient over-current fault reporting is not wanted, a simple 1ms RC low-pass filter in series with the fault flag circuit will prevent this momentary flag (Figure 4).
USB Controller OVERCURRENT 10k 10k
V+
2
IMP2525A FLG
0.1F
2525A_05.eps
Figure 4. Transient Filter
VCC 5.0V Upstream VBUS 100mA max VBUS D+ LDO D- GND GND 1F 1F GND GND 3 0.1F GND IN OUT VIN 10k 100k Ferrite Beads 8 VBUS D+ USB Port
ON/OFF
1 2
EN
OUT
OVERCURRENT 3.3V USB Controller
7 FLG IN IMP2525A-2 6 OUT 150F
+
D-
2525A_08.eps
Data
Data
Figure 5. Single-Port Self-Powered Hub Application
6
408-432-9100/www.impweb.com (c) 2000 IMP, Inc.
IMP2525A
Package Dimensions
Plastic DIP (8-Pin)
D1
Inches Min
A A1
E
Millimeters Max Min Max Plastic DIP (8-Pin)*
0.210 ----- 0.195 0.022 0.070 0.045 0.400 ----- 0.325 0.280 ----- ----- 0.430 0.060 0.150 0.069 0.010 0.020 0.010 2.92 1.35 0.10 0.33 0.19 1.27 0.157 0.244 0.050 0.197 3.80 5.80 0.40 4.80 4.00 6.20 1.27 5.00 3.81 1.75 0.25 0.51 0.25 ----- ---- 0.38 2.92 0.36 1.14 0.80 9.02 0.13 7.62 6.10 2.54 7.62 10.92 5.33 ----- 4.95 0.56 1.78 1.14 10.16 ----- 8.26 7.11
----- 0.015 0.115 0.014 0.045 0.030 0.355 0.005 0.300 0.240 0.100 0.300 ----- ----- 0.115 0.053 0.004 0.013 0.007 0.050 0.150 0.228 0.016 0.189
D A A2
A2 b b2 b3
E1
L A1 e b b2
0-15 C eA eB
Plastic DIP (8-Pin)a.eps
D D1 E E1 e eA
SO (8-Pin)
0- 8
eB eC
L
L A A1 B C
SO (8-Pin)**
E H
C D A
e E H L D
e B A1
SO (8-Pin).eps
* JEDEC Drawing MS-001BA ** JEDEC Drawing MS-012AA
(c) 2000 IMP, Inc.
USB High-Side Power Switches
7
Notes
Project
8
408-432-9100/www.impweb.com
(c) 2000 IMP, Inc.
IMP2526
POWER MANAGEMENT
Dual USB High-Side Power Switch
Key Features
N N N N N N N N USB Rev. 1.1 and 2.0 compliant 2.7V to 5.5V input operation Low MOSFET ON resistance (0.1 at 5V) Low supply current - 110A ON state current, 1A OFF state current 500mA continuous load current per switch 1.25A maximum current limit, 750mA typical Thermal shutdown 2.4V undervoltage lockout (UVLO) Open-drain flag output - Undervoltage - Current limit - Thermal shutdown Active HIGH(-1) and active LOW(-2) enable Pin compatible with the Micrel MIC2526
- Dual switch - 0.14 /0.1 "ON" resistance at 3/5V - MIC2526 pin compatible
The IMP2526 dual high-side power switch IC is designed for selfpowered and bus-powered Universal Serial Bus (USB) power supply and general purpose power management applications. ON resistance is a low 100m at 5V input and 140m at 3V input. The IMP2526 conforms to the new USB Revision 1.1 standard. Fault current is limited to 750mA typically, and a flag output for each switch conveys fault information to the local USB controller. The IMP2526 "SoftStart" function ramps the ON-current to eliminate any excessive voltage drop on the input side that could occur when capacitive loads are charged. Self-monitoring features include thermal shutdown to prevent catastrophic switch failure from high-current loads and undervoltage lockout (UVLO) that insures that the device remains OFF unless there is a sufficient supply voltage present. The switch Enable input logic can interface with both 3.3V and 5V logic. Both active-HIGH (-1 devices) and active-LOW (-2 devices) enable logic versions are available. Supply current is a low 0.75A when disabled and just 110A when enabled. The IMP2526 devices are available in 8-pin DIP and 8-pin SO packages and are pin compatible replacements for the Micrel MIC2526-1/-2. IMP
N N
offers a complete family of USB power management products. For single-switch applications see the IMP2525 and IMP2525A data sheets. The single-switch IMP2525A features a 50% lower switch resistance, 0.07. For quadswitch applications, refer to the IMP2524 data sheet.
Applications
N N N N USB host and self-powered hubs Bus-powered hubs Hot plug-in power supplies Battery chargers
2 FLGA
Block Diagrams
IMP2526
ENA 1 Charge Pump Gate Control
8
OUTA
Current Limit
Oscillator
Thermal Shutdown
UVLO
1.2V Reference
7
IN
Charge Pump ENB 4
Gate Control
Current Limit 5 3
OUTB FLGB
6
2526_01.eps
GND
(c) 2000 IMP, Inc.
408-432-9100/www.impweb.com
1
IMP2526
Pin Configuration
SO/DIP
IMP2526 ENA ENA FLGA FLGB ENB 1 2 3 4 IMP2526 8 7 6 5 OUTA IN GND OUTB
2526_02.eps
8
1 2 3 4 Logic, Charge Pump Logic, Charge Pump
OUTA
FLGA FLGB ENB
7
IN
5 6
OUTB
GND
2526_03.eps
Pin Descriptions
Pin Number
1, 4 2, 3 6 7 8, 5
Name
ENA, ENB FLGA, FLGB GND IN OUTA, OUTB
Function
Enable input. This pin is the MOSFET switch driver logic input. Both active-HIGH (-1 suffix) and active-LOW (-2 suffix) logic devices are available. Fault flag output. This open-drain output goes into an active-LOW state in response to undervoltage, current limit or thermal shutdown conditions. Ground. Power supply return for the internal circuitry of the IC. Positive power supply voltage input. This is the switching MOSFET drain connection as well as the positive supply for the IC. MOSFET source. The output pin supplies power to the load.
Ordering Information
Part Number
IMP2526-1BM IMP2526-2BM IMP2526-1BN IMP2526-2BN
Enable Logic
Active HIGH Active LOW Active HIGH Active LOW
Temperature Range
- 40C to +85C - 40C to +85C - 40C to +85C - 40C to +85C
Pins-Package
8-SO 8-SO 8-DIP 8-DIP
2
408-432-9100/www.impweb.com
(c) 2000 IMP, Inc.
IMP2526
Absolute Maximum Ratings
Supply Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . +6.0V Fault Flag Voltage . . . . . . . . . . . . . . . . . . . . . . +6.0V Fault Flag Current . . . . . . . . . . . . . . . . . . . . . . 50mA Output Voltage . . . . . . . . . . . . . . . . . . . . . . . . . +6.0V Output Current . . . . . . . . . . . . . . . . . . . . . . . . . Internally Limited Enable Input . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3V to 12V Storage Temperature . . . . . . . . . . . . . . . . . . . . . -65C to +150C Lead Temperature (Soldering, 5 sec.) . . . . . . . 260C Package Thermal Resistance SO (JA) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120C/W DIP(JA) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130C/W Note: All voltages are referenced to GND. These are stress ratings only and functional operation is not implied. Exposure to absolute maximum ratings for prolonged time periods may affect device reliability.
Electrical Characteristics
Unless otherwise noted, VIN = 5V and TA = 25C.
Parameter
Supply Voltage Range Operating Temperature Range Supply Current Switch OFF Supply Current Switch ON Enable Input Threshold Enable Input Current Enable Input Capacitance Switch ON Resistance Output Turn-On Delay Output Turn-On Rise Time Output Turn-Off Delay Output Turn-Off Fall Time Output Leakage Current Short-circuit Current Limit Overtemperature Shutdown Threshold Error Flag Output Resistance Error Flag Output Current UVLO Threshold
Symbol Conditions
VIN TA IIN OFF Switch OFF, No load VENOFF 0.8V, VENON 2.4V IMP2526-1 VENON 0.8V, VENOFF 2.4V IMP2526-2 Switch ON, No load VENOFF 0.8V, VENON 2.4V IMP2526-1 VENON 0.8V, VENOFF 2.4V IMP2526-2 LOW to HIGH ("0" to "1") Enable Voltage, Note 1 HIGH to LOW ("1" to "0") Enable Voltage, Note 1 VEN = 0V to 5.5V VIN = 5V, IOUT = 500mA VIN = 3.3V, IOUT = 500mA TDON TRON TDOFF TFOFF IOFF ISC TJ increasing TJ decreasing RFLAG IFLAG VUVLO VIN = 5V, IL = 10mA VIN = 3.3V, IL = 10mA VFLAG = 5V VIN Increasing VIN Decreasing RL = 10 each output RL = 10 each output RL = 10 each output RL = 10 each output TA = - 40C to +85C
Min
2.7 - 40
Typ
Max
5.5 85
Units
V C A
0.75
5
IIN ON
110
160
A
VENH VENL IEN CEN RON
2.1 0.8 -1 1.9 0.01 1 0.10 0.14 0.25 1 1 1 0.50 0.75 135 125 10 15 0.01 2.5 2.3
2.4 1 0.14 0.18
V A pF ms ms
20 20 10 1.25
s s A A C
25 40 1
A V
Notes 1. Switch OFF is VEN 0.8V and Switch ON is VEN 2.4V for the IMP2526-1. Switch OFF is VEN 2.4V and Switch ON is VEN 0.8V for the IMP2526-2. The Enable input has approximately 200mV of hysteresis.
(c) 2000 IMP, Inc.
USB High-Side Power Switches
3
IMP2526
Detailed Descriptions
The IMP2526 dual high-side N-channel MOSFET switch interfaces with a USB controller by means of a Switch-Enable input and a Fault-Flag output. The Enable input, with either a logic "1" for the IMP2526-1 or logic "0" for the IMP2526-2, turns the power MOSFET ON. Any one of three fault conditions will activate the open-drain Fault-Flag Output to alert the controller that the power MOSFET has been turned OFF.
Thermal Shutdown
Thermal shutdown is active when the output switch is enabled (turned ON). Thermal shutdown shuts off the output MOSFET and sets the Fault Flag if the on-chip temperature sensor exceeds 135C. The switch is held OFF until the die temperature drops to 125C or below. This 10C of hysteresis will result in ON-OFF short-circuit cycling if the short-circuit condition is not removed or the bus-controller does turn off the switch with the Enable input. Over temperature detection is active only if the chip is enabled.
Input and Output
The IN (input) pin is the power supply connection to the logic circuitry and the "High-Side" of the switch (the Drain of the power MOSFET). The OUTA/B (output) pin is the "Low-Side" of the switch (the Source of the power MOSFET). In a typical circuit, current flows through the switch from IN to OUT toward the load. The switch is referred to as a "High-Side" switch since it drives the positive (or high) side of the load. The output MOSFET source can be forced to a higher voltage than the drain (VOUT > VIN) when the output is OFF with little leakage current. If, however, VIN drops below 2.3V, reverse current may flow out the IN pin regardless of the enable state. When the power switch is ON, current can flow in either direction.
Undervoltage Lockout
The Undervoltage lockout (UVLO) prevents the output MOSFET from being put into the ON state until the positive supply voltage, VIN, exceeds 2.5V. When the output switch is in the ON state and the positive supply voltage drops below 2.3V, the UVLO circuitry will assert the Fault Flag, FLG, and shut OFF the output MOSFET. The FLG output will only assert an active LOW state when the MOSFET switch is in the ON state. Undervoltage detection is active only if the chip is enabled.
Fault Flag - FLG Pin
The Fault Flag pin, FLGA/B, connects to an N-channel, opendrain MOSFET and goes LOW ("0") for an occurrence of one or more of three conditions: undervoltage, current limit, or thermal shutdown. The FLG output MOSFET is capable of sinking a 10mA load to typically 100mV above ground. Both flags may be wire-NORed to a common pull-up resistor. Table 1 gives the states of the FLG and OUT pins when a fault condition is detected.
Current Limiting
Current limiting is achieved by sensing the voltage drop from Drain-to-Source of the power MOSFET. When the internal threshold is exceeded the power MOSFET is turned OFF.
Table 1. Fault Flag Conditions - Switch Enabled
Condition
Thermal Shutdown Undervoltage Lockout (UVLO) Current Limiting
Cause
TJ > 135C VIN < 2.3V IO > 0.5A (step load) IO > 0.63A (ramped load)
FLG pin "0" Until
TJ 125C VIN > 2.5V Enable off or Thermal Shutdown
Switch State (FLG = "0")
Turns OFF Turns OFF Stays ON*
* The switch and Fault Flag behavior during current-limiting is more complex than shown by this table. The detailed discussion on each of these fault conditions gives additional information.
4
408-432-9100/www.impweb.com
(c) 2000 IMP, Inc.
IMP2526
Application Information
Supply Filtering
IMP strongly recommends the use of a 0.1F to 1F bypass capacitor to control transients on the power supply pin. This capacitor, connected from IN to GND, should be in close proximity to the IMP2526 for maximum transient suppression. The lack of suitable bypassing can result in ringing on the IN input when transients occur. This ringing, due to supply lead inductance, could damage IMP2526 control circuitry if the 8V maximum input rating is exceeded.
2.7V to 5.5V
Enable Input
As with any logic input, the enable pins, ENA/ENB, must be driven to a definitive logic state at all times. Floating the input can result in spurious operation. Do not drive ENA/ENB below GND.
Fault Flag Output Soft Start
The IMP2526 provides a "Soft-Start" function that ramps up the ON-current to eliminate any excessive voltage drop that could occur due to charging a capacitive load in bus-powered applications. The "Soft-Start" results from a switch ON resistance, RON, that is ramped down from a high impedance to 0.14 in milliseconds. This RON ramping reduces the inrush current and related transients occur when charging capacitive loads; a requirement for meeting the USB voltage drop standards for bus-powered applications (see Figure 2). In circuits with large load capacitances, CBULK, exceeding 10F, the soft-start circuit shown in Figure 3 can be used to limit the inrush start-up current to USB transient specifications. The current limiting feature of the IMP2526 provides this high-load, soft-start operation.
IMP2526 IN 6 GND
7
0.1F to 1F
2526_04.eps
Figure 1. Supply Bypassing
USB Controller IMP2526-xBM VBUS 1 2 3 USB Host 4.7F GND Cable Bus Powered Hub Cable Downstream USB Device
2526_06.eps
ENA FLGA FLGB
OUTA IN GND
8 7 6 0.1F Capacitive Load CBULK
4 ENB
OUTB 5
Figure 2. Soft-Start Application
(c) 2000 IMP, Inc.
USB High-Side Power Switches
5
IMP2526
Application Information
USB Controller IMP2526-2 VBUS 1 ENA OUTA IN GND OUTB 8 7 CBULK 6 5 USB Function CBULK Cable USB Peripheral
2526_07.eps
USB Function
2 FLGA USB Hub 4.7F GND 3 FLGB 4 ENB
Figure 3. Inrush Current-Limit Application
Transient Overcurrent Filter
If a heavy capacitive load is suddenly connected to the output, the switch current-limiting function may cause the fault-flag to go low for 10s to 200s as the switch, in a constant current mode, charges the capacitance. If this transient over-current fault reporting is not wanted, a simple 1ms RC low-pass filter in series with the fault flag circuit will prevent this momentary flag (Figure 4).
USB Controller OVERCURRENT 0.1F 10k 10k
V+
2
IMP2526 FLG
2526_05.eps
Figure 4. Transient Filter
10k 10k Upstream VBUS 100mA max VBUS D+ D- GND 1F LDO GND 1F VBUS Data 47F D+ IN OUT 3.3V USB Controller VIN ON/OFF 8 ENA OUTA IMP2526-2 7 2 FLGA IN 3 FLGB GND 6 4 5 ENB OUTB 1 100k 100k Ferrite Beads VBUS
VCC 5.0V
+
0.1F
OVERCURRENT OVERCURRENT ON/OFF
47F
D+ D- GND USB Port 1
+
D- GND
USB Port 2
Data (Two Pair)
2526_08.eps
Figure 5. Single-Port Self-Powered Hub Application
6
408-432-9100/www.impweb.com (c) 2000 IMP, Inc.
IMP2526
Package Dimensions
Plastic DIP (8-Pin)
D1
Inches Min
A A1
E
Millimeters Max Min Max Plastic DIP (8-Pin)*
0.210 ----- 0.195 0.022 0.070 0.045 0.400 ----- 0.325 0.280 ----- ----- 0.430 0.060 0.150 0.069 0.010 0.020 0.010 2.92 1.35 0.10 0.33 0.19 1.27 0.157 0.244 0.050 0.197 3.80 5.80 0.40 4.80 4.00 6.20 1.27 5.00 3.81 1.75 0.25 0.51 0.25 ----- ---- 0.38 2.92 0.36 1.14 0.80 9.02 0.13 7.62 6.10 2.54 7.62 10.92 5.33 ----- 4.95 0.56 1.78 1.14 10.16 ----- 8.26 7.11
----- 0.015 0.115 0.014 0.045 0.030 0.355 0.005 0.300 0.240 0.100 0.300 ----- ----- 0.115 0.053 0.004 0.013 0.007 0.050 0.150 0.228 0.016 0.189
D A A2
A2 b b2 b3
E1
L A1 e b b2
0-15 C eA eB
Plastic DIP (8-Pin)a.eps
D D1 E E1 e eA
SO (8-Pin)
0- 8
eB eC
L
L A A1 B C
SO (8-Pin)**
E H
C D A
e E H L D
e B A1
SO (8-Pin).eps
* JEDEC Drawing MS-001BA ** JEDEC Drawing MS-012AA
(c) 2000 IMP, Inc.
USB High-Side Power Switches
7
Notes
Project
8
408-432-9100/www.impweb.com
(c) 2000 IMP, Inc.
IMP, Inc. Corporate Headquarters 2830 N. First Street San Jose, CA 95134-2071 Tel: 408-432-9100 Fax: 408-434-0335 e-mail: info@impinc.com http://www.impweb.com
The IMP logo is a registered trademark of IMP, Inc. All other company and product names are trademarks of their respective owners.
2000 (c) IMP, Inc. Printed in USA Publication #: 5001 Revision: C Issue Date: 07/13/00 Type: Preliminary

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