MAX4978MAX4981 19-4137 Rev 0 5/08 Overvoltage Protector with Active Current Limit General Description Features Input Voltage Protection Up to +28V The MAX4978MAX4981 overvoltage-protection devices protect low-voltage systems against voltage faults up to Integrated nFET Switch, 85m (typ) +28V and feature a low 85m R FET, an active cur- ON Preset Overvoltage Protection Trip Level rent limiter, and lithium-ion battery overcharge protec- 5.7V (typ) (MAX4978/MAX4980/MAX4981) tion (MAX4980/MAX4981). These devices are used to 6.8V (typ) (MAX4979) protect the charger input port on a portable device. Low-Current Undervoltage Lockout Mode The overvoltage protector feature protects against volt- Overcurrent Protection ages up to 28V with two different trip thresholds: 5.7V Internal 160ms (typ) Startup Delay (MAX4978/MAX4980/MAX4981) and 6.8V (MAX4979). Thermal-Shutdown Protection There is an undervoltage protector with two different trip Battery Overcharge Protection thresholds: 4.4V (MAX4978) and 2.63V (MAX4979/ (MAX4980/MAX4981) MAX4980/MAX4981). Startup Debounce Time Indicator The overcurrent limiter and battery voltage monitor fea- (MAX4978/MAX4979) tures provide a second layer of protection for a lithium- Small, 8-Pin (2mm x 3mm) TDFN Package ion battery charger. The overcurrent limiter is available in two different thresholds: 0.9A (MAX4978/MAX4979/ Pin Configuration MAX4980) and 1.95A (MAX4981). Once current reach- es the threshold, it is held for a 20ms blanking time. If TOP VIEW the current is still at the limit after the blanking time, the OUT I.C. I.C. GND FET is turned off, and the device restarts the cycle after 867 5 160ms. The battery voltage monitor measures the volt- age of a lithium-ion battery and disables the FET if the battery voltage reaches 4.4V (MAX4980/MAX4981). The MAX4978MAX4981 are available in a small 8-pin TDFN (2mm x 3mm) package and are specified over MAX4978 the extended -40C to +85C temperature range. MAX4979 MAX4980 MAX4981 Applications *EP Cell Phones PDAs and Palmtop Devices MP3 Players 132 4 Digital Still Cameras SDT(BAT) IN I.C. EN TDFN-EP (BAT) IS FOR MAX4980/MAX4981 ONLY. Typical Application Circuit appears at end of data sheet. *EP = EXPOSED PAD. CONNECT EP TO GND. Ordering Information/Selector Guide CURRENT BATTERY UVLO OVLO TOP PKG PART PIN-PACKAGE LIMIT (mA) MONITOR (V) (V) MARK CODE MAX4978ETA+ 8 TDFN-EP* 900 No 4.4 5.7 AAK T823-1 MAX4979ETA+** 8 TDFN-EP* 900 No 2.63 6.8 AAL T823-1 8 TDFN-EP* MAX4980ETA+ 900 Yes 2.63 5.7 AAM T823-1 MAX4981ETA+ 8 TDFN-EP* 1950 Yes 2.63 5.7 AAN T823-1 Note: All devices specified over the -40C to +85C operating temperature range. +Denotes a lead-free package. *EP = Exposed pad. **Future productcontact factory for availability. Maxim Integrated Products 1 For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxims website at www.maxim-ic.com.Overvoltage Protector with Active Current Limit ABSOLUTE MAXIMUM RATINGS (Voltages referenced to GND.) Junction-to-Case Thermal Resistance ( ) (Note 1) JC IN, SDT ................................................................. -0.3V to +30V 8-Pin 2mm x 3mm TDFN ......................................... 10.8C/W OUT ........................................................................... -0.3V to IN Junction-to-Ambient Thermal Resistance ( ) (Note 1) JA EN, BAT .................................................................. -0.3V to +6V 8-Pin 2mm x 3mm TDFN ............................................ 60C/W SDT Continuous Current ................................................. 50mA Operating Temperature Range ......................... -40C to +85C Continuous Power Dissipation (T = +70C) Junction Temperature .................................................... +150C A 8-Pin 2mm x 3mm TDFN (derate 16.7mW/C Storage Temperature Range ........................... -65C to +150C above +70C) ........................................................... 1333mW Lead Temperature (soldering, 10s) ................................+300C Note 1: Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a 4-layer board. For detailed information on package thermal considerations, refer to www.maxim-ic.com/thermal-tutorial. 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 (V = 5.0V, V = 0V, T = -40C to +85C, unless otherwise noted. Typical values are at T = +25C.) (Note 2) IN EN A A PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS Input Voltage Range V 2.3 28 V IN Input Supply Current I I < I 130 190 A IN OUT LIM MIN UVLO Supply Current I V = 2.3V 35 60 A UVLO IN Shutdown Supply Current I V = 5V 15 23 A SHDN EN V falling 4.2 IN MAX4978 V rising 4.3 4.4 4.5 IN IN Undervoltage Lockout V V UVLO V falling 2.5 MAX4979/MAX4980/ IN MAX4981 V rising 2.56 2.63 2.70 IN IN Undervoltage Lockout 1% Hysteresis V falling 5.5 MAX4978/MAX4980/ IN MAX4981 V rising 5.6 5.7 5.8 IN IN Overvoltage Lockout V V OVLO V falling 6.5 IN MAX4979 V rising 6.65 6.80 6.95 IN IN Overvoltage Lockout Hysteresis 1% BAT Overvoltage Trip Level V MAX4980/MAX4981, V rising 4.3 4.4 4.5 V BOTL BAT BAT Overvoltage Hysteresis MAX4980/MAX4981 1 % BAT Input Leakage Current I MAX4980/MAX4981, V = 4.2V 1 A LKGB BAT Switch On-Resistance R I = 100mA 85 160 m ON OUT T =+25C 850 900 950 A MAX4978, MAX4979, T = 0C to +85C 800 1000 A MAX4980 Overcurrent Protection Threshold I T = -40C to +0C 780 1000 mA LIM A T =+25C 1850 1950 2050 A MAX4981 T = -40C to +85C 1750 1950 2150 A Thermal Shutdown T T rising 160 C SHDN A 2 MAX4978MAX4981