19-3776; Rev 0; 7/05 Overvoltage-Protection Controller with Internal Disconnect Switch Features 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. ♦ Overvoltage Protection Up to 28V 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 -40°C to +85°C temperature range. ♦ Tiny 10-Pin TDFN Package Applications ♦ 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 Ordering Information PART TEMP RANGE PINPACKAGE TOP MARK MAX4880ETB -40°C to +85°C 10 TDFN-EP* APJ * EP = Exposed Pad Cell Phones Digital Still Cameras Typical Operating Circuit PDAs and Palmtop Devices MP3 Players Pin Configuration BAT_OK BTB_SNS BTB GND IN FLAGV TOP VIEW AC-DC ADAPTER 5.25V 10 9 8 7 6 GATE BTA VIO BTB MAX4880 Li+ MAX4880 BTB_SNS 2 3 4 5 IN EN GATE BTA CB FLAGV BAT_OK CB EN 1 DC-DC CONVERTER GND 3mm x 3mm TDFN ________________________________________________________________ Maxim Integrated Products 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. 1 MAX4880 General Description MAX4880 Overvoltage-Protection Controller with Internal Disconnect Switch 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 = +70°C) 10-Pin TDFN (derate 18.5mW/°C above +70°C) ...1481.5mW Operating Temperature Range ...........................-40°C to +85°C Junction Temperature .................................................... +150°C Storage Temperature Range ............................-65°C to +150°C Lead Temperature (soldering, 10s) ................................+300°C 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 = -40°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.) (Note 1) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS 28.0 V 5.7 V INPUT VOLTAGE (IN) Input Voltage Range Overvoltage Trip Level VIN 1.2 OVLO VIN rising 5.5 5.6 UVLO VIN falling 4.2 4.35 Overvoltage-Trip-Level Hysteresis Undervoltage-Lockout Threshold 50 Undervoltage-Lockout Hysteresis Supply Current mV 4.5 50 IIN + IBTA No load, VIN = 5.4V, VEN = 0 or 5.5V, VCB = 0 or VIN 240 V mV 380 µA 2.8 5.7 V 2.4 2.7 V INTERNAL SWITCH BTA Input Range BTA Undervoltage Lockout VBTA BTAUVLO Falling edge BTA-Undervoltage-Lockout Hysteresis BTB-Switch-Disconnect Trip Level 50 BTBTRIP 4.10 BTB-Switch-Disconnect Hysteresis Switch-Forward Current Limit Switch-Reverse Current Limit mV 4.20 200 IFWD IREV 450 mV 600 600 650 Voltage Drop (VBTA – VBTB) IL = 400mA BTB Off Current VEN = 0 (VCB = 0, or VIN < VUVLO and VBTA = 0) IBTB-OFF 525 TA = +25°C V mA mA 110 mV 1 µA GATE GATE Voltage GATE Pulldown Current VGATE IPD IGATE sourcing 1µA , VIN = 5V 9 VIN > VOVLO, VGATE = 5V 10 60 V mA TIMING GATE Startup Delay tSTART VIN > VUVLO, VGATE > 0.3V (Figure 1) 20 50 80 ms FLAGV Delay Time tDELAY VGATE = 0.3V,VFLAGV = 2.4V (Figure 1) 20 50 80 ms GATE Turn-On Time tGON VGATE = 0.3V to 8V, CGATE = 1500pF (Figure 1) 7 tGOFF VIN increasing from 5V to 8V at 3V/µs, VGATE = 0.3V, CGATE = 1500pF (Figure 2) 6 GATE Turn-Off Time 2 _______________________________________________________________________________________ ms 20 µs Overvoltage-Protection Controller with Internal Disconnect Switch (VIN = 5V, TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.) (Note 1) PARAMETER SYMBOL FLAGV Assertion Delay tFLAGV CONDITIONS MIN TYP MAX UNITS VIN increasing from 5V to 8V at 3V/µs, VFLAGV = 0.4V (Figure 2) 5.8 µs Initial Overvoltage Fault Delay tOVP VIN increasing from 0 to 8V, IGATE = 80% of IPD (Figure 3) 100 ns Disable Time tDIS VEN = 2.4V, VGATE = 0.3V (Figure 4) 580 ns EN, CB INPUTS Input-High Voltage VIH Input-Low Voltage VIL 1.4 V Input Leakage 0.5 V 1 µA 0.4 V 1 µA FLAGV, BAT_OK OUTPUTS Output Voltage Low ISINK = 1mA, FLAGV, BAT_OK assert VOL Leakage Current VBAT_OK = VFLAGV = 5.5V THERMAL PROTECTION Thermal Shutdown +150 °C Thermal Hysteresis 40 °C Note 1: All devices are 100% tested at TA = +25°C. Electrical limits over the full temperature range are guaranteed by design. Typical Operating Characteristics (VIN = 5V, TA = +25°C, otherwise noted.) 250 200 150 100 50 GATE VOLTAGE vs. INPUT VOLTAGE 0 MAX4880 toc02 300 9 250 200 150 100 10 15 20 INPUT VOLTAGE (V) 6 UVLO TRIP POINT 3 0 5 OVLO TRIP POINT 50 UVLO TRIP POINT 0 12 GATE VOLTAGE (V) 300 350 IIN + IBTA CURRENT (μA) IIN + IBTA CURRENT (μA) VEN = 0 VCB = 5V MAX4880 toc01 OVLO TRIP POINT 350 IIN + IBTA CURRENT vs. TEMPERATURE 400 MAX4880 toc03 IIN + IBTA CURRENT vs. INPUT VOLTAGE 400 25 30 0 -40 -15 10 35 TEMPERATURE (°C) 60 85 0 1 2 3 4 5 6 INPUT VOLTAGE (V) 7 _______________________________________________________________________________________ 8 3 MAX4880 ELECTRICAL CHARACTERISTICS (continued) Typical Operating Characteristics (continued) (VIN = 5V, TA = +25°C, otherwise noted.) MAX4880 toc04 4.08 4.04 BTB OFF CURRENT (nA) 4.12 4.12 4.08 4.04 4.00 5.1 5.2 5.3 5.4 5.5 INPUT VOLTAGE (V) 5.6 5.7 VEN = 0V VCB = 0V VBTB = 5.5V 100 10 1 0.1 4.00 5.0 1000 MAX4880 toc05 4.16 BTB TRIP LEVEL (V) 4.16 BTB OFF CURRENT vs. TEMPERATURE BTB TRIP LEVEL vs. TEMPERATURE 4.20 MAX4880 toc06 BTB TRIP LEVEL vs. INPUT VOLTAGE 4.20 BTB TRIP LEVEL (V) MAX4880 Overvoltage-Protection Controller with Internal Disconnect Switch -40 -15 10 35 TEMPERATURE (°C) 60 85 POWER-UP RESPONSE -40 -15 10 35 TEMPERATURE (°C) POWER-DOWN RESPONSE MAX4880 toc07 MAX4880 toc08 5V 5V IN 60 IN 0 0 10V GATE 0 5V BTA 10V GATE 0 5V BTA 0 0 5V FLAGV 0 5V FLAGV 0 20ms/div 20ms/div EN vs. GATE OVERVOLTAGE RESPONSE MAX4880 toc09 MAX4880 toc10 8V 5V IN EN 0 5V 10V 10V GATE 0 50mA GATE 0 IGATE 0 5V FLAGV 100μs/div 4 0 400ns/div _______________________________________________________________________________________ 85 Overvoltage-Protection Controller with Internal Disconnect Switch CURRENT LIMIT vs. TEMPERATURE CURRENT LIMIT vs. VBTB 700 CURRENT LIMIT (mA) CURRENT LIMIT (mA) 600 500 400 300 200 100 VCB = 5V VBTA = 5V 700 600 MAX4880 toc12 800 MAX4880 toc11 800 500 400 300 200 VCB = 5V VBTA = 5V VBTB = 3.6V 100 0 0 -40 -15 10 35 TEMPERATURE (°C) 60 85 1.0 1.5 2.0 2.5 3.0 VBTB (V) 3.5 4.0 4.5 Pin Description PIN NAME FUNCTION 1 IN Input. IN is the power input for the overvoltage (OVP) charge pump. Bypass IN to GND with a 1µF or larger capacitor to achieve 15kV ESD protection. 2 EN 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. 3 GATE 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. 4 BTA 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 0.1µF capacitor as close to the device as possible. 5 CB 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. 6 GND Ground 7 BTB 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. 8 BTB_SNS Battery-Voltage-Sensing Input. BTB_SNS must be connected to BTB for proper operation. Bypass BTB_SNS to GND with a 0.1µF capacitor as close to the device as possible. 9 BAT_OK 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. _______________________________________________________________________________________ 5 MAX4880 Typical Operating Characteristics (continued) (VIN = 5V, TA = +25°C, otherwise noted.) Overvoltage-Protection Controller with Internal Disconnect Switch MAX4880 Pin Description (continued) PIN NAME 10 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 VIN VUVLO tGON 1.2V 8V VOVLO 5V tFLAG tGOFF 8V tSTART VGATE VGATE 0.3V 0.3V tDELAY 2.4V VFLAGV 0.4V Figure 1. Startup Timing Diagram VIN VFLAGV Figure 2. Overvoltage Fault Timing Diagram VEN VOVLO 2.4V 0V tOVP tDIS 80% IGATE Figure 3. Power-Up Overvoltage Timing Diagram 6 VGATE 0.3V Figure 4. Disable Timing Diagram _______________________________________________________________________________________ Overvoltage-Protection Controller with Internal Disconnect Switch IN GATE IN OVLO UVLO 10V CHARGE PUMP BTA BAT_OK FLAGV BTA UVLO 525mA LIMIT 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 1µA when the adapter is not present. 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. IREF CHARGE PUMP BTB BTB_SNS CB VREF MAX4880 GND 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. 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. 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. 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) IN Overvoltage Lockout (OVLO) 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. 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. 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, Internal Switch Control Input (CB) _______________________________________________________________________________________ 7 MAX4880 IN Undervoltage Lockout (UVLO) EN MAX4880 Overvoltage-Protection Controller with Internal Disconnect Switch RC 1MΩ CHARGE-CURRENTLIMIT RESISTOR HIGHVOLTAGE DC SOURCE Cs 100pF RD 1.5kΩ IP 100% 90% DISCHARGE RESISTANCE STORAGE CAPACITOR Ir PEAK-TO-PEAK RINGING (NOT DRAWN TO SCALE) AMPERES DEVICE UNDER TEST 36.8% 10% 0 0 Figure 6. Human-Body ESD Test Model TIME tRL tDL CURRENT WAVEFORM Figure 7. Human-Body-Model Current Waveform I 100% CHARGE-CURRENTLIMIT RESISTOR HIGHVOLTAGE DC SOURCE Cs 150pF RD 330Ω 90% DISCHARGE RESISTANCE STORAGE CAPACITOR I PEAK RC 50Ω to 100Ω DEVICE UNDER TEST 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. 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 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. IN Bypass Considerations Bypass IN to GND with a 1µF 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 _______________________________________________________________________________________ Overvoltage-Protection Controller with Internal Disconnect Switch MAX4880 Table 1. MOSFET Suggestions PART CONFIGURATION/ PACKAGE VDS MAX (V) RON AT 4.5V (mΩ) Si1426DH Single/SC70-6 30 115 Vishay Siliconix www.vishay.com 402-563-6866 FDG315N Single/SC70-6 30 160 Fairchild Semiconductor www.fairchildsemi.com 207-775-8100 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. 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 1µF low-ESR ceramic capacitor. Contact Maxim for a reliability report that documents test setup, methodology, and results. MANUFACTURER 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. 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 1.5kΩ resistor. Chip Information TRANSISTOR COUNT: 2391 PROCESS: BiCMOS _______________________________________________________________________________________ 9 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.) 6, 8, &10L, DFN THIN.EPS MAX4880 Overvoltage-Protection Controller with Internal Disconnect Switch D2 D A2 PIN 1 ID N 0.35x0.35 b PIN 1 INDEX AREA E [(N/2)-1] x e REF. E2 DETAIL A e k A1 CL CL A L L e e PACKAGE OUTLINE, 6,8,10 & 14L, TDFN, EXPOSED PAD, 3x3x0.80 mm -DRAWING NOT TO SCALE- 21-0137 G 1 2 COMMON DIMENSIONS MIN. MAX. D 0.70 2.90 0.80 3.10 E A1 2.90 0.00 3.10 0.05 L k 0.20 0.40 0.25 MIN. A2 0.20 REF. SYMBOL A PACKAGE VARIATIONS PKG. CODE N D2 E2 e JEDEC SPEC b [(N/2)-1] x e DOWNBONDS ALLOWED T633-1 6 1.50±0.10 2.30±0.10 0.95 BSC MO229 / WEEA 0.40±0.05 1.90 REF NO T633-2 6 1.50±0.10 2.30±0.10 0.95 BSC MO229 / WEEA 0.40±0.05 1.90 REF NO T833-1 8 1.50±0.10 2.30±0.10 0.65 BSC MO229 / WEEC 0.30±0.05 1.95 REF NO T833-2 8 1.50±0.10 2.30±0.10 0.65 BSC MO229 / WEEC 0.30±0.05 1.95 REF NO T833-3 8 1.50±0.10 2.30±0.10 0.65 BSC MO229 / WEEC 0.30±0.05 1.95 REF YES T1033-1 10 1.50±0.10 2.30±0.10 0.50 BSC MO229 / WEED-3 0.25±0.05 2.00 REF NO T1433-1 14 1.70±0.10 2.30±0.10 0.40 BSC ---- 0.20±0.05 2.40 REF YES T1433-2 14 1.70±0.10 2.30±0.10 0.40 BSC ---- 0.20±0.05 2.40 REF 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 © 2005 Maxim Integrated Products Jackson Printed USA is a registered trademark of Maxim Integrated Products. Products, Inc.