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19-3776; Rev 0; 7/05
Overvoltage-Protection Controller with Internal Disconnect Switch
General Description
The MAX4880 is an overvoltage-protection controller with an internal current-limited switch that can be configured as a low-cost battery charger. When the input voltage exceeds the overvoltage trip level (5.7V), or drops below the undervoltage-lockout level (4.2V), the MAX4880 turns off the external n-channel MOSFET and asserts an undervoltage/overvoltage flag indicator (FLAGV) low to notify the processor. The MAX4880 internal current-limited switch limits the charge current flowing to the battery to 525mA. The switch opens when the battery voltage reaches its fullcharged state (4.2V), and a flag (BAT_OK) asserts to notify the processor. The MAX4880 includes a switchcontrol input (CB) to turn off the internal current-limited switch, regardless of the battery voltage. The MAX4880 also features a built-in startup delay that allows the adapter voltage to settle down before turning on the MOSFET. Other features include 15kV ESD protection for the input and a shutdown function (EN) to turn off the external n-channel MOSFET. The MAX4880 is available in a space-saving 10-pin TDFN package and is specified for operation over the extended -40C to +85C temperature range. Overvoltage Protection Up to 28V Preset 5.6V Overvoltage Trip Level Internal 525mA Current-Limited Switch 1.2% Accurate Battery Disconnect (4.2V) Drives Low-Cost n-Channel MOSFET Internal 50ms Startup Delay Overvoltage/Undervoltage-Fault FLAGV Indicator Battery-Voltage-Trip BAT_OK Indicator Undervoltage Lockout Thermal Shutdown Protection Tiny 10-Pin TDFN Package
Features
MAX4880
Ordering Information
PART MAX4880ETB TEMP RANGE -40C to +85C PINPACKAGE 10 TDFN-EP* TOP MARK APJ
Applications
Cell Phones Digital Still Cameras PDAs and Palmtop Devices MP3 Players
* EP = Exposed Pad
Typical Operating Circuit
AC-DC ADAPTER 5.25V IN GATE BTA
Pin Configuration
BAT_OK FLAGV
TOP VIEW
BTB_SNS
GND
10
9
8
BTB
VIO
7
6
DC-DC CONVERTER Li+ BTB_SNS
BTB
MAX4880
MAX4880
FLAGV BAT_OK CB EN
1 IN
2 EN
3 GATE
4 BTA
5 CB
GND
3mm x 3mm TDFN ________________________________________________________________ Maxim Integrated Products 1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at 1-888-629-4642, or visit Maxim's website at www.maxim-ic.com.
Overvoltage-Protection Controller with Internal Disconnect Switch MAX4880
ABSOLUTE MAXIMUM RATINGS
(All voltages referenced to GND.) IN ............................................................................-0.3V to +30V GATE ......................................................................-0.3V to +12V EN, CB, FLAGV, BAT_OK, BTA, BTB, BTB_SNS .....-0.3V to +6V Continuous Power Dissipation (TA = +70C) 10-Pin TDFN (derate 18.5mW/C above +70C) ...1481.5mW 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 = 5V, TA = -40C to +85C, unless otherwise noted. Typical values are at TA = +25C.) (Note 1)
PARAMETER INPUT VOLTAGE (IN) Input Voltage Range Overvoltage Trip Level Overvoltage-Trip-Level Hysteresis Undervoltage-Lockout Threshold Undervoltage-Lockout Hysteresis Supply Current INTERNAL SWITCH BTA Input Range BTA Undervoltage Lockout BTA-Undervoltage-Lockout Hysteresis BTB-Switch-Disconnect Trip Level BTB-Switch-Disconnect Hysteresis Switch-Forward Current Limit Switch-Reverse Current Limit Voltage Drop (VBTA - VBTB) BTB Off Current GATE GATE Voltage GATE Pulldown Current TIMING GATE Startup Delay FLAGV Delay Time GATE Turn-On Time GATE Turn-Off Time tSTART tDELAY tGON tGOFF VIN > VUVLO, VGATE > 0.3V (Figure 1) VGATE = 0.3V,VFLAGV = 2.4V (Figure 1) VGATE = 0.3V to 8V, CGATE = 1500pF (Figure 1) VIN increasing from 5V to 8V at 3V/s, VGATE = 0.3V, CGATE = 1500pF (Figure 2) 20 20 50 50 7 6 20 80 80 ms ms ms s VGATE IPD IGATE sourcing 1A , VIN = 5V VIN > VOVLO, VGATE = 5V 9 60 10 V mA IBTB-OFF IFWD IREV TA = +25C IL = 400mA VEN = 0 (VCB = 0, or VIN < VUVLO and VBTA = 0) 450 BTBTRIP 4.10 200 525 600 600 650 110 1 VBTA BTAUVLO Falling edge 2.8 2.4 50 4.20 5.7 2.7 V V mV V mV mA mA mV A IIN + IBTA No load, VIN = 5.4V, VEN = 0 or 5.5V, VCB = 0 or VIN UVLO VIN falling 4.2 VIN OVLO VIN rising 1.2 5.5 5.6 50 4.35 50 240 380 4.5 28.0 5.7 V V mV V mV A SYMBOL CONDITIONS MIN TYP MAX UNITS
2
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Overvoltage-Protection Controller with Internal Disconnect Switch
ELECTRICAL CHARACTERISTICS (continued)
(VIN = 5V, TA = -40C to +85C, unless otherwise noted. Typical values are at TA = +25C.) (Note 1)
PARAMETER FLAGV Assertion Delay Initial Overvoltage Fault Delay Disable Time EN, CB INPUTS Input-High Voltage Input-Low Voltage Input Leakage FLAGV, BAT_OK OUTPUTS Output Voltage Low Leakage Current THERMAL PROTECTION Thermal Shutdown Thermal Hysteresis +150 40 C C VOL ISINK = 1mA, FLAGV, BAT_OK assert VBAT_OK = VFLAGV = 5.5V 0.4 1 V A VIH VIL 1.4 0.5 1 V V A SYMBOL tFLAGV tOVP tDIS CONDITIONS VIN increasing from 5V to 8V at 3V/s, VFLAGV = 0.4V (Figure 2) VIN increasing from 0 to 8V, IGATE = 80% of IPD (Figure 3) VEN = 2.4V, VGATE = 0.3V (Figure 4) MIN TYP 5.8 100 580 MAX UNITS s ns ns
MAX4880
Note 1: All devices are 100% tested at TA = +25C. Electrical limits over the full temperature range are guaranteed by design.
Typical Operating Characteristics
(VIN = 5V, TA = +25C, otherwise noted.)
IIN + IBTA CURRENT vs. INPUT VOLTAGE
MAX4880 toc01
IIN + IBTA CURRENT vs. TEMPERATURE
MAX4880 toc02
GATE VOLTAGE vs. INPUT VOLTAGE
OVLO TRIP POINT 9 GATE VOLTAGE (V)
MAX4880 toc03
400 350 IIN + IBTA CURRENT (A) 300 250 200 150 100 50 0 0 5 10 15 20 INPUT VOLTAGE (V) 25 UVLO TRIP POINT OVLO TRIP POINT VEN = 0 VCB = 5V
400 350 IIN + IBTA CURRENT (A) 300 250 200 150 100 50 0
12
6 UVLO TRIP POINT 3
0 -40 -15 10 35 TEMPERATURE (C) 60 85 0 1 2 3 4 5 6 INPUT VOLTAGE (V) 7 8
30
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3
Overvoltage-Protection Controller with Internal Disconnect Switch MAX4880
Typical Operating Characteristics (continued)
(VIN = 5V, TA = +25C, otherwise noted.)
BTB TRIP LEVEL vs. INPUT VOLTAGE
MAX4880 toc04
BTB TRIP LEVEL vs. TEMPERATURE
MAX4880 toc05
BTB OFF CURRENT vs. TEMPERATURE
VEN = 0V VCB = 0V VBTB = 5.5V
MAX4880 toc06
4.20
4.20 4.16 BTB TRIP LEVEL (V)
1000
4.16 BTB TRIP LEVEL (V)
4.12
4.12
BTB OFF CURRENT (nA)
100
10
4.08
4.08
4.04
4.04
1
4.00 5.0 5.1 5.2 5.3 5.4 5.5 INPUT VOLTAGE (V) 5.6 5.7
4.00 -40 -15 10 35 TEMPERATURE (C) 60 85
0.1 -40 -15 10 35 TEMPERATURE (C) 60 85
POWER-UP RESPONSE
MAX4880 toc07
POWER-DOWN RESPONSE
MAX4880 toc08
IN
5V IN 0 10V
5V 0 10V GATE 0 5V 0 5V FLAGV 0 20ms/div
GATE 0 BTA 5V 0 5V FLAGV 0 20ms/div
BTA
EN vs. GATE
MAX4880 toc09
OVERVOLTAGE RESPONSE
MAX4880 toc10
5V EN 0 IN
8V 5V 10V GATE 0 50mA IGATE 0 5V FLAGV 0 400ns/div
10V GATE 0
100s/div
4
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Overvoltage-Protection Controller with Internal Disconnect Switch MAX4880
Typical Operating Characteristics (continued)
(VIN = 5V, TA = +25C, otherwise noted.) CURRENT LIMIT vs. TEMPERATURE
MAX4880 toc11
CURRENT LIMIT vs. VBTB
700 600 CURRENT LIMIT (mA) 500 400 300 200 VCB = 5V VBTA = 5V
MAX4880 toc12
800 700 600 CURRENT LIMIT (mA) 500 400 300 200 100 0 -40 -15 10 35 TEMPERATURE (C) 60 VCB = 5V VBTA = 5V VBTB = 3.6V
800
100 0 85 1.0 1.5 2.0 2.5 3.0 VBTB (V) 3.5 4.0 4.5
Pin Description
PIN 1 2 NAME IN EN FUNCTION Input. IN is the power input for the overvoltage (OVP) charge pump. Bypass IN to GND with a 1F or larger capacitor to achieve 15kV ESD protection. Active-Low Enable Input. Driving EN high turns off the external MOSFET. Pulling EN low activates the overvoltage-protection circuitry and turns on the external MOSFET. Gate-Drive Output. GATE is the output of an on-chip OVP charge pump. When VUVLO < VIN < VOVLO, GATE is driven high to turn on the external n-channel MOSFET. When VIN (MIN) < VIN < VUVLO or VIN > VOVLO, GATE is driven low to turn off the external n-channel MOSFET. Input Terminal for the Internal-Current-Limited Switch. Connect BTA to the source of the external nchannel MOSFET. BTA is the power input for the entire device (except the OVP charge pump). Bypass BTA to GND with a 0.1F capacitor as close to the device as possible. Control Input for the Internal-Current-Limited Switch. Drive CB high to leave the internal switch control for the internal logic. The internal switch turns on and off depending on the battery voltage level. The internal switch turns off when the battery voltage reaches the BTB trip level (4.2V), and turns back on when the battery falls by 200mV. Driving CB low turns off the internal switch regardless of the battery voltage. Ground Output Terminal for the Internal-Current-Limited Switch. When the BTB voltage exceeds the trip level (4.2V), the internal switch opens. The switch closes only when the BTB voltage drops 200mV below the trip level. Battery-Voltage-Sensing Input. BTB_SNS must be connected to BTB for proper operation. Bypass BTB_SNS to GND with a 0.1F capacitor as close to the device as possible. Active-Low, Open-Drain, Battery-Voltage-Limit Flag Output. BAT_OK asserts low when the voltage on BTB exceeds the BTB trip level (4.2V). BAT_OK is disabled when EN goes high.
3
GATE
4
BTA
5
CB
6 7
GND BTB
8 9
BTB_SNS BAT_OK
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5
Overvoltage-Protection Controller with Internal Disconnect Switch MAX4880
Pin Description (continued)
PIN 10 -- NAME FLAGV EP FUNCTION Active-Low, Open-Drain-Fault Flag Output. FLAGV goes low when either an overvoltage or undervoltage fault occurs at IN. FLAGV is disabled when EN goes high. During startup, FLAGV has a delay of 50ms after VGATE > 0.3V, before being initially driven high. Exposed Pad. EP is internally connected to GND. Do not use EP as the only electrical ground connection.
5V VIN 1.2V VUVLO tGON 8V tSTART VGATE 0.3V tDELAY 2.4V VFLAGV
VIN
8V VOVLO 5V tGOFF tFLAG
VGATE 0.3V
VFLAGV 0.4V
Figure 1. Startup Timing Diagram
Figure 2. Overvoltage Fault Timing Diagram
VIN 0V
VOVLO tOVP 80%
VEN
2.4V tDIS
VGATE 0.3V
IGATE
Figure 3. Power-Up Overvoltage Timing Diagram
Figure 4. Disable Timing Diagram
6
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Overvoltage-Protection Controller with Internal Disconnect Switch MAX4880
IN Undervoltage Lockout (UVLO)
EN GATE
IN
IN OVLO UVLO
10V CHARGE PUMP BTA
The MAX4880 includes a fixed 4.35V typical undervoltage-lockout level (UVLO). When VIN is below the VUVLO (1.2V VIN 4.35V), GATE goes low to turn off the external n-channel MOSFET. In addition, the driver for the internal switch (BTA-BTB) is also turned off; therefore, this switch is open. This ensures the reverse current, drained from the battery, is less than 1A when the adapter is not present.
BAT_OK
525mA LIMIT
BTA UVLO
Fault Flag Output (FLAGV)
The FLAGV output signals the host system that there is a fault with the input voltage. FLAGV asserts low in response to either an overvoltage or an undervoltage fault. FLAGV stays low for 50ms after GATE turns on, before deasserting high. FLAGV is an open-drain, active-low output. Connect a pullup resistor from FLAGV to the logic I/O voltage of the host system or to any voltage source up to 6V. FLAGV is invalid when driving EN high.
FLAGV
IREF CHARGE PUMP BTB BTB_SNS VREF CB
MAX4880
GND
Battery-Voltage-Limit Flag Output (BAT_OK)
The MAX4880 includes a battery-voltage-limit flag output (BAT_OK). BAT_OK asserts low to indicate the voltage on BTB exceeds the BTB trip level of 4.2V. BAT_OK deasserts high when the voltage on BTB falls by the BTB hysteresis voltage of more than 200mV. BAT_OK is an open-drain, active-low output. Connect a pullup resistor from BAT_OK to the logic I/O voltage of the host system, or to any voltage source up to 6V. BAT_OK is invalid when driving EN high.
Figure 5. Functional Diagram
Detailed Description
The MAX4880 provides up to 28V overvoltage protection for low-voltage systems. When the input voltage at IN exceeds the overvoltage trip level (OVLO), the MAX4880 turns off a low-cost, external n-channel MOSFET to prevent damage to the protected components and issues an overvoltage fault flag. When the correct adapter is plugged in, the n-channel MOSFET is turned on. The output of the MOSFET is then connected to the internal current-limit switch that provides the charge-current path to the battery. When the battery reaches the trip voltage (4.2V), the internal switch turns off and BAT_OK asserts low, indicating that the battery has reached its full charged state. The internal switch turns back on only when the battery voltage drops by more than 200mV.
EN Input
The MAX4880 features an active-low enable input (EN). Drive EN low or connect to ground for normal operation. Drive EN high to force the external n-channel MOSFET off, disabling FLAGV and BAT_OK.
Internal Current Limit (BTA to BTB)
The internal switch from BTA to BTB has a preset current-limit of 525mA (typ). If the load current from BTA to BTB reaches this current limit, the switch operates in the continuous mode, limiting the load current to the preset value. The switch remains in the current-limit condition until the battery voltage on BTB exceeds 4.2V, or until the control bit CB is driven low to open the switch.
IN Overvoltage Lockout (OVLO)
The MAX4880 has a 5.6V typical overvoltage threshold (OVLO). When VIN is higher than VOVLO, GATE goes low to turn off the external n-channel MOSFET. An overvoltage FLAGV is asserted low to notify the processor of the fault condition.
Internal Switch Control Input (CB)
The CB input controls the internal switch. When CB is high, the on/off state of the internal switch depends on the battery voltage level. The internal switch turns off when the battery voltage reaches the BTB trip level,
7
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Overvoltage-Protection Controller with Internal Disconnect Switch MAX4880
RC 1M CHARGE-CURRENTLIMIT RESISTOR HIGHVOLTAGE DC SOURCE RD 1.5k DISCHARGE RESISTANCE DEVICE UNDER TEST
IP 100% 90% AMPERES 36.8% 10% 0 0 tRL TIME
Ir
PEAK-TO-PEAK RINGING (NOT DRAWN TO SCALE)
Cs 100pF
STORAGE CAPACITOR
tDL CURRENT WAVEFORM
Figure 6. Human-Body ESD Test Model
Figure 7. Human-Body-Model Current Waveform
I 100%
RC 50 to 100 CHARGE-CURRENTLIMIT RESISTOR HIGHVOLTAGE DC SOURCE
RD 330
I PEAK
90%
DISCHARGE RESISTANCE DEVICE UNDER TEST
Cs 150pF
STORAGE CAPACITOR
10% t r = 0.7ns TO 1ns t 30ns 60ns
Figure 8. IEC 61000-4-2 ESD Test Model
Figure 9. IEC 61000-4-2 ESD Generator Current
and turns back on when the battery falls below the BTB trip level minus BTB hysteresis. Drive CB low to turn off the internal switch, regardless of the battery voltage. This control bit can be used to provide additional topoff charge for the battery. When the CB pin is cycled, the internal battery switch is turned on and off. This effectively provides an average current that is lower than the full-charge current.
Applications Information
MOSFET Selection
The MAX4880 is designed for use with an n-channel MOSFET. MOSFETs with RDS(ON) specified for a VGS of 4.5V are ideal. If the input supply is near the UVLO minimum of 4.2V, consider using a MOSFET specified for a lower VGS voltage. Also, the VDS should be 30V for the MOSFET to withstand the full 28V IN range of the MAX4880. Table 1 shows a selection of MOSFETs appropriate for use with the MAX4880.
GATE Driver
An on-chip charge pump drives the GATE voltage to approximately twice VIN, allowing the use of a low-cost, n-channel MOSFET (Figure 5). The actual GATE output voltage tracks approximately 2 x VIN, until VIN exceeds the OVLO trip level, 5.6V (typ). The GATE output voltage, as a function of input voltage, is shown in the Typical Operating Characteristics.
8
IN Bypass Considerations
Bypass IN to GND with a 1F ceramic capacitor to achieve 15kV ESD-protected input. When the power source has significant inductance due to long lead length, take care to prevent overshoots due to the LC
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Overvoltage-Protection Controller with Internal Disconnect Switch MAX4880
Table 1. MOSFET Suggestions
PART CONFIGURATION/ PACKAGE Single/SC70-6 VDS MAX (V) 30 RON AT 4.5V (m) 115 Vishay Siliconix www.vishay.com 402-563-6866 Fairchild Semiconductor www.fairchildsemi.com 207-775-8100 MANUFACTURER
Si1426DH
FDG315N
Single/SC70-6
30
160
tank circuit and provide protection if necessary to prevent exceeding the 30V absolute maximum rating on IN. The MAX4880 provides protection against voltage faults up to 28V, but this does not include negative voltages. If negative voltages are a concern, connect a Schottky diode from IN to GND to clamp negative input voltages.
IEC 61000-4-2
Since January 1996, all equipment manufactured and/or sold in the European community has been required to meet the stringent IEC 61000-4-2 specification. The IEC 61000-4-2 standard covers ESD testing and performance of finished equipment; it does not specifically refer to integrated circuits. The MAX4880 helps users design equipment that meets Level 3 of IEC 61000-4-2, without additional ESD-protection components. The main difference between tests done using the Human Body Model and IEC 61000-4-2 is higher peak current in IEC 61000-4-2. Because series resistance is lower in the IEC 61000-4-2 ESD test model (Figure 8), the ESD-withstand voltage measured to this standard is generally lower than that measured using the Human Body Model. Figure 9 shows the current waveform for the 8kV IEC 61000-4-2 Level 4 ESD ContactDischarge test. The Air-Gap test involves approaching the device with a charger probe. The ContactDischarge method connects the probe to the device before the probe is energized.
Exposed Pad
The MAX4880 provides an exposed pad on the bottom of the package. This pad is internally connected to GND. For the best thermal conductivity and higher power dissipation, solder the exposed pad to the ground plane. Do not use the ground-connected pad as the only electrical ground connection or ground return. Use GND (pin 6) as the primary electrical ground connection.
ESD Test Conditions
ESD performance depends on a number of conditions. The MAX4880 is specified for 15kV typical ESD resistance on IN when IN is bypassed to ground with a 1F low-ESR ceramic capacitor. Contact Maxim for a reliability report that documents test setup, methodology, and results.
Human Body Model
Figure 6 shows the Human Body Model, and Figure 7 shows the current waveform it generates when discharged into a low impedance. This model consists of a 100pF capacitor charged to the ESD voltage of interest, which is then discharged into the device through a 1.5k resistor.
Chip Information
TRANSISTOR COUNT: 2391 PROCESS: BiCMOS
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9
Overvoltage-Protection Controller with Internal Disconnect Switch MAX4880
Package Information
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information go to www.maxim-ic.com/packages.)
D2 D A2
N
PIN 1 ID
0.35x0.35 b
PIN 1 INDEX AREA
E DETAIL A
E2 e
[(N/2)-1] x e REF.
A1
k
C L
C L
A
L e e
L
PACKAGE OUTLINE, 6,8,10 & 14L, TDFN, EXPOSED PAD, 3x3x0.80 mm
-DRAWING NOT TO SCALE-
21-0137
G
1 2
COMMON DIMENSIONS SYMBOL A D E A1 L k A2 MIN. 0.70 2.90 2.90 0.00 MAX. 0.80 3.10 3.10 0.05
0.20 0.40 0.25 MIN. 0.20 REF.
PACKAGE VARIATIONS PKG. CODE T633-1 T633-2 T833-1 T833-2 T833-3 T1033-1 T1433-1 T1433-2 N 6 6 8 8 8 10 14 14 D2 1.500.10 1.500.10 1.500.10 1.500.10 1.500.10 1.500.10 1.700.10 1.700.10 E2 2.300.10 2.300.10 2.300.10 2.300.10 2.300.10 2.300.10 2.300.10 2.300.10 e 0.95 BSC 0.95 BSC 0.65 BSC 0.65 BSC 0.65 BSC 0.50 BSC 0.40 BSC 0.40 BSC JEDEC SPEC MO229 / WEEA MO229 / WEEA MO229 / WEEC MO229 / WEEC MO229 / WEEC MO229 / WEED-3 ------b 0.400.05 0.400.05 0.300.05 0.300.05 0.300.05 0.250.05 0.200.05 0.200.05 [(N/2)-1] x e 1.90 REF 1.90 REF 1.95 REF 1.95 REF 1.95 REF 2.00 REF 2.40 REF 2.40 REF
DOWNBONDS ALLOWED
NO NO NO NO YES NO YES NO
PACKAGE OUTLINE, 6,8,10 & 14L, TDFN, EXPOSED PAD, 3x3x0.80 mm
-DRAWING NOT TO SCALE-
21-0137
G
2 2
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.
10 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 (c) 2005 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products, Inc. Products.
Jackson
6, 8, &10L, DFN THIN.EPS

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