View MAX4917BELTT_799096.PDF datasheet online --- IC-ON-LINE

Datasheet File OCR Text:

19-0544; Rev 2; 6/08
100mA/200mA/300mA Current-Limit Switches with Low Shutdown Reverse Current
General Description
The MAX4914B/MAX4915A/B/MAX4917A/B family of switches feature internal current limiting to prevent damage to host devices due to faulty load conditions. These analog switches have a low 0.2 on-resistance and operate from a 2.3V to 5.5V input voltage range. They are available with guaranteed 100mA, 200mA, and 300mA current limits, making them ideal for SDIO and other load switching applications. When the switch is on and a load is connected to the port, a guaranteed blanking time of 14ms ensures that the transient voltages settle down. If after this blanking time the load current is greater than the current limit, the MAX4914B/MAX4915B/MAX4917B latchoff versions enter a latchoff state where the switch is turned off and FLAG is issued to the microprocessor. The switch can be turned on again by cycling the power or the ON pin. The MAX4915A/MAX4917A have an autoretry feature where the switch turns off after the blanking time and then continuously checks to see if the overload condition is present. The switch turns on and remains on after the overload condition disappears and FLAG deasserts. The MAX4914B is available in the tiny 6-pin DFN (2mm x 2mm) package, while the MAX4915A/B and MAX4917A/B are available in both 6-pin DFN (2mm x 2mm) and space-saving 5-pin SOT23 packages. These devices operate over the -40C to +85C extended temperature range. Thermal-Shutdown Protection Reverse Current Protection 0.2 On-Resistance 14ms Guaranteed Blanking Time FLAG Function 80A Supply Current 8A Latchoff Current (MAX4914B/MAX4915B/MAX4917B) Autoretry (MAX4915A/MAX4917A) 0.01A Shutdown Current 2.3V to 5.5V Supply Range Undervoltage Lockout Fast Current-Limit Response Time (5s) Low (0.1A typ) Reverse Shutdown Current Tiny 6-Pin DFN (2mm x 2mm) and 5-Pin SOT23 Packages
Features
Guaranteed Current Limit: 100mA, 200mA, 300mA
MAX4914B/MAX4915A/B/MAX4917A/B
Applications
PDAs and Palmtop Devices Cell Phones GPS Systems Handheld Devices SDIO USB Ports Notebook Computers
Ordering Information/Selector Guide
PART MAX4914BELT+T MAX4915AELT+T MAX4915AEUK+T* MAX4915BELT+T MAX4915BEUK+T* MAX4917AELT+T MAX4917AEUK+T* MAX4917BELT+T MAX4917BEUK+T* PIN-PACKAGE 6 DFN 6 DFN 5 SOT23 6 DFN 5 SOT23 6 DFN 5 SOT23 6 DFN 5 SOT23 TOP MARK ABF ABL AEYN ABG AEYK ABN AEYP ABI AEYM CURRENT LIMIT (mA) 100 200 200 200 200 300 300 300 300 RETRY/LATCH-OFF Latchoff Autoretry Autoretry Latchoff Latchoff Autoretry Autoretry Latchoff
Latchoff Note: All devices are specified over the -40C to +85C operating temperature range. *Future product--contact factory for availability. +Denotes a lead-free/RoHS-compliant package. T = Tape-and-reel package. Pin Configurations and Typical Operating Circuit appear at end of data sheet. ________________________________________________________________ Maxim Integrated Products 1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim's website at www.maxim-ic.com.
100mA/200mA/300mA Current-Limit Switches with Low Shutdown Reverse Current MAX4914B/MAX4915A/B/MAX4917A/B
ABSOLUTE MAXIMUM RATINGS
IN, ON, FLAG, OUT to GND .....................................-0.3V to +6V OUT Short Circuit to GND .................................Internally Limited Continuous Power Dissipation (TA = +70C) 5-Pin SOT23 (derate 7.1mW/C above +70C)............571mW 6-Pin DFN (derate 4.5mW/C above +70C)................358mW Operating Temperature Range ...........................-40C to +85C Junction Temperature ......................................................+150C Storage Temperature Range .............................-65C to +150C Lead Temperature (soldering, 10s) .................................+300C
Stresses beyond those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
ELECTRICAL CHARACTERISTICS
(VIN = +2.3V to +5.5V, TA = -40C to +85C, unless otherwise noted. Typical values are at VIN = +3.3V, TA = +25C.) (Note 1)
PARAMETER Operating Voltage Quiescent Current Latchoff Current (Note 2) Forward Shutdown Current Reverse Shutdown Current Forward Current Limit SYMBOL VIN IQ ILATCH ISHDN ISHDN IFWD VON = VIN, IOUT = 0, switch on VIN = +2.3V to +5.0V VIN = +5.0V to +5.5V 8 0.01 0.01 100 200 300 CONDITIONS MIN 2.3 80 TYP MAX 5.5 120 160 17 1 1 150 300 450 150 300 450 -1 1.75 100 RON VIH VIL TA = +25C, IOUT = 95mA TA = -40C to +85C, IOUT = 95mA MAX4914B/MAX4915B/MAX4917B MAX4915A/MAX4917A MAX4914B/MAX4915B/MAX4917B MAX4915A/MAX4917A ISINK = 1mA VON = VIN = V FLAG = +5.5V +150 15 VON from low to high; IOUT = 10mA, CL = 0.1F (Note 3) 2.0 1.4 0.8 0.4 0.4 1 0.2 0.4 0.5 +1 2.25 A V mV V V V A C C mA mA UNITS V A A A A
VON = VIN, after an overcurrent fault MAX4914B/ MAX4915B/MAX4917B (latchoff versions) VON = 0, VOUT = 0, VIN = +5.5V VON = 0, VOUT = +5.5V, VIN = +2.3V MAX4914B, VOUT = GND MAX4915_, VOUT = GND MAX4917_, VOUT = GND MAX4914B, VOUT - VIN 0.5V
Reverse Current Limit ON Input Leakage Undervoltage Lockout Undervoltage-Lockout Hysteresis On-Resistance ON Input Logic-High Voltage ON Input Logic-Low Voltage FLAG Output Logic-Low Voltage FLAG Output-High Leakage Current Thermal Shutdown Thermal-Shutdown Hysteresis DYNAMIC CHARACTERISTICS Turn-On Time
IREV
MAX4915_, VOUT - VIN 0.5V MAX4917_, VOUT - VIN 0.5V VON = VIN or GND
UVLO
Rising edge
100
s
2
_______________________________________________________________________________________
100mA/200mA/300mA Current-Limit Switches with Low Shutdown Reverse Current
ELECTRICAL CHARACTERISTICS (continued)
(VIN = +2.3V to +5.5V, TA = -40C to +85C, unless otherwise noted. Typical values are at VIN = +3.3V, TA = +25C.) (Note 1)
PARAMETER Turn-Off Time Blanking Time Short-Circuit Current-Limit Response Time Retry Time (Note 4) tRETRY tBLANK SYMBOL CONDITIONS VON from high to low; IOUT = 10mA, CL = 0.1F (Note 3) Overcurrent fault (Figures 2, 3) VON = VIN = +3.3V, short circuit applied to OUT MAX4915A/MAX4917A (autoretry versions) (Figure 2) (Note 4) 210 14 5 900 MIN TYP 40 60 MAX UNITS ns ms s ms
MAX4914B/MAX4915A/B/MAX4917A/B
Note 1: All parts are 100% tested at +25C. Limits across the full temperature range are guaranteed by design and correlation. Note 2: Latchoff current does not include the current flowing into FLAG. Note 3: The on-time is defined as the time taken for the current through the switch to go from 0mA to 10mA. The off-time is defined as the time taken for the current through the switch to go from 10mA to 0mA. Note 4: Retry time is typically 15 times the blanking time.
Typical Operating Characteristics
(VIN = 3.3V, TA = +25C, unless otherwise noted.)
QUIESCENT CURRENT vs. SUPPLY VOLTAGE
MAX4914A/B toc01
QUIESCENT CURRENT vs. TEMPERATURE
MAX4914A/B toc02
LATCHOFF CURRENT vs. TEMPERATURE
VON = VIN 10 LATCHOFF CURRENT (A) 8 VIN = 5V 6 4 VIN = 3.3V 2 0
MAX4914A/B toc03
100 90 QUIESCENT CURRENT (A) 80 70 60 50 40 30 20 10 0 2.0 2.5 3.0 3.5 4.0 4.5 5.0 VON = VIN
120 VON = VIN 100 QUIESCENT CURRENT (A) 80 60 VIN = 3.3V 40 20 0 VIN = 5V
12
5.5
-40
-15
10
35
60
85
-40
-15
10
35
60
85
SUPPLY VOLTAGE (V)
TEMPERATURE (C)
TEMPERATURE (C)
FORWARD SHUTDOWN CURRENT vs. TEMPERATURE
MAX4914A/B toc04
REVERSE SHUTDOWN CURRENT vs. TEMPERATURE
ON = GND, VOUT = 5.5V REVERSE SHUTDOWN CURRENT (nA) VIN = 5V
MAX4914A/B toc05
LATCHOFF LEAKAGE CURRENT vs. TEMPERATURE
MAX4914A/B toc06
1000 FORWARD SHUTDOWN CURRENT (nA) VCC = 5V
1
100 LATCHOFF LEAKAGE CURRENT (nA) 10 1 0.1 VIN = 3.3V 0.01 0.001
100
VIN = 5V
10 VCC = 3.3V 1
0.1
VIN = 3.3V
0.1
0.01 -40 -15 10 35 60 85 TEMPERATURE (C)
0.01 -40
0.0001 -15 10 35 60 85 -40 -15 10 35 60 85 TEMPERATURE (C) TEMPERATURE (C)
_______________________________________________________________________________________
3
100mA/200mA/300mA Current-Limit Switches with Low Shutdown Reverse Current MAX4914B/MAX4915A/B/MAX4917A/B
Typical Operating Characteristics (continued)
(VIN = 3.3V, TA = +25C, unless otherwise noted.)
NORMALIZED ON-RESISTANCE vs. TEMPERATURE
MAX4914A/B toc07
OUTPUT CURRENT vs. OUTPUT VOLTAGE
MAX4914A/B toc08
SWITCH TURN-ON/OFF TIMES vs. TEMPERATURE
ILOAD = 10mA ON 10
MAX4914A/B toc09
1.4 VCC = 5V 1.2 NORMALIZED RON 1.0 0.8 0.6 0.4 0.2 0 -40 -15 10 35 60
500 450 400 OUTPUT CURRENT (mA) 350 300 250 200 150 100 50 0 MAX4915_
100 SWITCH TURN-ON/OFF TIMES (s)
1
0.1
OFF
0.01 0 0.3 0.6 0.9 1.2 1.5 1.8 2.1 2.4 2.7 3.0 3.3 VIN - VOUT (V) -40 -15 10 35 60 85 TEMPERATURE (C)
85
TEMPERATURE (C)
FLAG-BLANKING TIMEOUT vs. TEMPERATURE
MAX4914A/B toc10
CURRENT-LIMIT RESPONSE (VON RISING)
MAX4914A/B toc11
CURRENT-LIMIT RESPONSE (VIN AND VON RISING TOGETHER)
MAX4914A/B toc12
50 FLAG-BLANKING TIMEOUT (ms) 45 40 35 30 25 20 -40 -15 10 35 60
CIN = 0.1F COUT = 0.1F
VIN 2V/div 0V
VIN = VON 1V/div
VON 2V/div 0V IOUT 100mA/div 0mA 85 20s/div TEMPERATURE (C)
0V
IOUT 100mA/div CIN = 0.1F COUT = 0.1F 20s/div
0mA
CURRENT-LIMIT RESPONSE (OUT SHORTED TO GND)
MAX4914A/B toc13
TURN-ON RESPONSE
MAX4914A/B toc14
CIN = 1F COUT = 0.1F
VIN 2V/div 0V
VON 1V/div
VOUT 2V/div 0V
0V
IOUT 50mA/div IOUT 5A/div 0A 40s/div 20s/div CIN = 0.1F COUT = 0.1F 0mA
4
_______________________________________________________________________________________
100mA/200mA/300mA Current-Limit Switches with Low Shutdown Reverse Current
Typical Operating Characteristics (continued)
(VIN = 3.3V, TA = +25C, unless otherwise noted.)
MAX4914B/MAX4915A/B/MAX4917A/B
TURN-OFF RESPONSE
MAX4914A/B toc15
FLAG-BLANKING RESPONSE
MAX4914A/B toc16
CIN = 0.1F COUT = 0.1F VON 1V/div
VIN 2V/div
CIN = 0.1F COUT = 0.1F 0V VON 2V/div 0V VFLAG 2V/div 0V IOUT 200mA/div 0mA 10ms/div
0V IOUT 10mA/div
0mA 200ns/div
Pin Description
PIN MAX4915A/B/ MAX4917A/B (SOT23) 1 2 3 4 MAX4914A/B/ MAX4915A/B/ MAX4917A/B (DFN) 2 5 6 4 NAME FUNCTION
IN GND ON FLAG
Input. Bypass with a 0.1F ceramic capacitor to ground as close to the device as possible. Ground Active-High, Switch-On Input. A logic-high turns the switch on. Fault Output. This open-drain output goes low when the device stays in forward or reverse current limit for more than the blanking time period. FLAG is high impedance when a fault is not present or when ON is low. Switch Output. Bypass with a 0.1F ceramic capacitor to ground as close to the device as possible. No Connection. Not internally connected.
5 --
3 1
OUT N.C.
_______________________________________________________________________________________
5
100mA/200mA/300mA Current-Limit Switches with Low Shutdown Reverse Current MAX4914B/MAX4915A/B/MAX4917A/B
REVERSE CURRENT DETECTOR FLAG BLANKING TIME CIRCUITRY N
FORWARD CURRENT DETECTOR IN
N
OUT
ON
UNDERVOLTAGE LOCKOUT
+2.0V
LOGIC AUTORETRY
MAX4914B MAX4915A/B MAX4917A/B
GND
Figure 1. Functional Diagram
Detailed Description
The MAX4914B/MAX4915A/B/MAX4917A/B are forward/reverse current-limited switches that operate from a +2.3V to +5.5V input voltage range and guarantee a 100mA, 200mA, and 300mA minimum current-limit threshold for different options. The voltage drop across an internal sense resistor is compared to two reference voltages to indicate a forward or reverse current-limit fault. When the load current exceeds the preset current limit for greater than the fault-blanking time, the switch opens and FLAG asserts. The MAX4915A/MAX4917A have an autoretry function that turns on the switch again after an internal retry time expires. If the faulty load condition is still present after the blanking time, the switch turns off again and the cycle is repeated. If the faulty load condition is not present, the switch remains on. During this retry time, FLAG remains low until the fault is removed. The MAX4914B/MAX4915B/MAX4917B do not have the autoretry option, and the switch remains in latchoff mode until the ON pin or the input power is cycled from high to low and then high again. The undervoltage-lockout (UVLO) circuit prevents erroneous switch operation when the input voltage goes too low.
6
Reverse Current Protection
All devices limit the reverse current (VOUT to VIN) from exceeding the maximum IREV value. The switch is shut off and FLAG is asserted if the reverse current-limit condition persists for more than the blanking time. This feature prevents excessive reverse currents from flowing through the device to the source. When the device is in shutdown (VON < VIL), the current from OUT to IN does not exceed 1A (max).
Switch-On/Off Control
Toggle ON high to enable the current-limited switches. The switches are continuously on only if VIN exceeds the UVLO threshold (typically 2V) and there is no fault. When a forward/reverse current fault is present or the die exceeds the thermal-shutdown temperature of +150C, OUT is internally disconnected from IN and the supply current decreases to 8A (latchoff). The switch is now operating in one of its off states. The switch-off state also occurs when driving ON low, thus reducing the supply current (shutdown) to 0.01A (typ). Table 1 illustrates the ON/OFF state.
FLAG Indicator
All devices feature a latched fault output, FLAG. Whenever a fault is activated, it latches the FLAG output low and also turns the switch off. FLAG is an open-
_______________________________________________________________________________________
100mA/200mA/300mA Current-Limit Switches with Low Shutdown Reverse Current MAX4914B/MAX4915A/B/MAX4917A/B
Table 1. MAX4914B/MAX4915A/B/MAX4917A/B Switch Truth Table
ON Low High High FAULT X Undervoltage lockout Thermal OFF OFF OFF immediately (tBLANK period does not apply) OFF after tBLANK period has elapsed ON during tBLANK period, OFF during tRETRY period for the MAX4915A/MAX4917A (autoretry versions); cycle repeats until fault is removed SWITCH ON/OFF SUPPLY CURRENT MODE Shutdown Shutdown Latchoff Latchoff See the Autoretry (MAX4915A/MAX4917A) section
High
Current limit
tBLANK
tRETRY
tBLANK
tBLANK CURRENT LIMIT SHORT CONDITION REMOVED
ON SWITCH STATUS OFF
FLAG STATUS
Figure 2. MAX4915A/MAX4917A Autoretry Fault-Blanking Diagram
drain output transistor and requires an external pullup resistor from FLAG to IN. During shutdown (VON < VIL), the pulldown on the FLAG output is released in order to limit power dissipation. FLAG goes low when any of the following conditions occur: * The die temperature exceeds the thermal-shutdown temperature limit of +150C. * The device is in current limit for more than the faultblanking period. * VIN is below the UVLO threshold. For the MAX4915A/MAX4917A (autoretry versions), FLAG stays low until the overcurrent condition is removed (See Figure 2).
Autoretry (MAX4915A/MAX4917A)
When the forward or reverse current-limit threshold is exceeded, tBLANK timer begins counting (Figure 2). The timer resets if the overcurrent condition disappears
before tBLANK has elapsed. A retry time delay, tRETRY, is started immediately after tBLANK has elapsed, and during that time, the switch is latched off. At the end of tRETRY, the switch is turned on again. If the fault still exists, the cycle is repeated. If the fault has been removed, the switch stays on. The autoretry feature saves system power in the case of an overcurrent or short-circuit condition. During tBLANK, when the switch is on, the supply current is at the current limit. During tRETRY, when the switch is off, the current through the switch is zero. Instead of observing the full load current, the switch sees the equivalent load current times duty cycle or ISUPPLY = I LOAD t BLANK / (t BLANK + t RETRY ). With a typical tBLANK = 37ms and typical tRETRY = 555ms, the duty cycle is 6%, which results in a 94% power savings over the switch being on the entire time. The duty cycle is consistent across the process and devices.
_______________________________________________________________________________________
7
100mA/200mA/300mA Current-Limit Switches with Low Shutdown Reverse Current MAX4914B/MAX4915A/B/MAX4917A/B
FIGURE 3a tBLANK tBLANK
LOAD CURRENT ON SWITCH STATUS ON PIN VOLTAGE
device to enter current limit, an internal counter starts. If the load-transient fault persists beyond the fault-blanking timeout, FLAG asserts low. Load-transient faults less than tBLANK do not cause a FLAG output assertion. Only current-limit faults are blanked. A thermal fault and input voltage drops below the UVLO threshold cause FLAG to assert immediately and not wait for the blanking time.
OFF
Thermal Shutdown
The MAX4914B/MAX4915A/B/MAX4917A/B have a thermal-shutdown feature to protect the devices from overheating. The switch turns off and FLAG goes low immediately (no fault blanking) when the junction temperature exceeds +150C. The switch turns back on when the device temperature drops approximately by 15C.
FLAG PIN STATUS
FIGURE 3b tBLANK LOAD CURRENT tBLANK
Applications Information
Input Capacitor
To limit the input-voltage drop during momentary output short-circuit conditions, connect a capacitor from IN to GND. A 0.1F ceramic capacitor is adequate for most applications; however, higher capacitor values further reduce the voltage drop at the input and are recommended for lower voltage applications.
UVLO
ON SWITCH STATUS
OFF
IN PIN VOLTAGE FLAG PIN STATUS
Output Capacitance
Connect a 0.1F capacitor from OUT to GND. This capacitor helps prevent inductive parasitics from pulling OUT negative during turn-off, thus preventing the devices from tripping erroneously. If the load capacitance is too large, the current may not have enough time to charge the capacitance and the device assumes that there is a faulty load condition. The maximum capacitive load value that can be driven from OUT is obtained by the following formula: CMAX < IFWD _ MIN x tBLANK _ MIN VIN
Figure 3. MAX4914B/MAX4915B/MAX4917B Latchoff Fault Blanking
Latchoff (MAX4914B/MAX4915B/MAX4917B)
When the forward or reverse current-limit threshold is exceeded, the tBLANK timer begins counting. The timer resets if the overcurrent condition disappears before tBLANK has elapsed. The switch is shut off if the overcurrent condition continues up to the end of the blanking time. Reset the switch by either toggling ON (Figure 3a) or cycling the input voltage below UVLO, typically 2V (Figure 3b).
Layout and Thermal Dissipation
To optimize the switch response time to output shortcircuit conditions, it is very important to keep all traces as short as possible to reduce the effect of undesirable parasitic inductance. Place input and output capacitors as close as possible to the device (no more than 5mm). IN and OUT pins must be connected with short traces to the power bus. During normal operation, the power dissipation is small and the package temperature change is minimal. If the output is continuously shorted to ground at the maximum
Fault Blanking
All devices feature 14ms (min) fault blanking. Fault blanking allows current-limit faults, including momentary short-circuit faults that occur when hot-swapping a capacitive load, and also ensures that no fault is issued during power-up. When a load transient causes the
8
_______________________________________________________________________________________
100mA/200mA/300mA Current-Limit Switches with Low Shutdown Reverse Current MAX4914B/MAX4915A/B/MAX4917A/B
supply voltage, the operation of the switches with the autoretry option does not cause problems because the total power dissipated during the short is scaled by the duty cycle: PMAX = VIN _ MAX x IOUT _ MAX x tBLANK tRETRY + tBLANK = 155mW Attention must be given to the MAX4914B/MAX4915B/ MAX4917B (latchoff versions), where the latchoff condition must be manually reset by toggling ON from high to low. If the latchoff time duration is not sufficiently high, it is possible for the device to reach the thermalshutdown threshold and never be able to turn the device on until it cools down.
where VIN = 5.5V, IOUT = 450mA, tBLANK = 14ms, and tRETRY = 210ms.
Pin Configurations
TOP VIEW +
IN 1 GND 2 ON 3 5 OUT + N.C. 1 IN 2 4 FLAG OUT 3 6 ON
MAX4915A/B MAX4917A/B
MAX4914B 5 GND MAX4915A/B MAX4917A/B
4 FLAG
SOT23
DFN (2mm x 2mm)
Typical Operating Circuit
2.3V TO 5.5V
IN ON P
MAX4914B FLAG MAX4915A/B MAX4917A/B
OUT GND
TO SDIO PORT
Chip Information
PROCESS: BiCMOS
_______________________________________________________________________________________
9
100mA/200mA/300mA Current-Limit Switches with Low Shutdown Reverse Current MAX4914B/MAX4915A/B/MAX4917A/B
Package Information
For the latest package outline information and land patterns, go to www.maxim-ic.com/packages. PACKAGE TYPE 6 DFN 5 SOT23 PACKAGE CODE L622-1 U5-2 DOCUMENT NO. 21-0164 21-0057
10
______________________________________________________________________________________
100mA/200mA/300mA Current-Limit Switches with Low Shutdown Reverse Current
Revision History
REVISION NUMBER 0 1 2 REVISION DATE 5/06 12/06 6/08 Initial release Removed future product notes. Added new VIH and VIL EC table specs for the MAX4915 Changed VIH and VIL EC table specs for the MAX4917A DESCRIPTION PAGES CHANGED -- -- 2
MAX4914B/MAX4915A/B/MAX4917A/B
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 ____________________ 11
(c) 2008 Maxim Integrated Products is a registered trademark of Maxim Integrated Products, Inc.

▲Up To Search▲

Price & Availability of MAX4917BELTT

	To Download MAX4917BELTT Datasheet File
If you can't view the Datasheet, Please click here to try to view without PDF Reader .