19-2024; Rev 2; 6/03 USB-Powered Li+ Charger Features ♦ Charges Single-Cell Li+ Batteries Directly from USB Port The MAX1811 has preconditioning that soft-starts a near-dead battery cell before charging. Other safety features include continuous monitoring of voltage and current and initial checking for fault conditions before charging. ♦ Protected by U.S. Patent # 6,507,172 ♦ 0.5% Overall Charging Accuracy ♦ Minimal External Components ♦ Input Diode Not Required ♦ Automatic IC Thermal Regulation ♦ Preconditions Near-Depleted Cells ♦ Convenient Power SO-8 Package (1.4W) The MAX1811 is available in a small 1.4W thermally enhanced 8-pin SO package. ________________________Applications PDAs and Palmtops Ordering Information PART Digital Still Cameras MAX1811ESA TEMP RANGE PIN-PACKAGE -40°C to +85°C 8 SO MP3 Players Cell Phones Two-Way Pagers Hand-Held Computers Typical Operating Circuit TO LOAD BATT 4.35V TO 6.5V SINGLE Li+ CELL IN 4.2V TOP VIEW SELV 1 SELI 2 8 CHG 7 EN 3 6 GND IN 4 5 BATT SELV 4.1V ON TO IN MAX1811 MAX1811 LED GND EN OFF CHG 500mA 100mA Pin Configuration SELI GND CHG LOGIC OUT SO * Protected by U.S. Patent # 6,507,172 ________________________________________________________________ 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 MAX1811 General Description The MAX1811 is a single-cell lithium-ion (Li+) battery charger that can be powered directly from a USB port* or from an external supply up to 6.5V. It has a 0.5% overall battery regulation voltage accuracy to allow maximum utilization of the battery capacity. The charger uses an internal FET to deliver up to 500mA charging current to the battery. The device can be configured for either a 4.1V or 4.2V battery, using the SELV input. The SELI input sets the charge current to either 100mA or 500mA. An open-drain output (CHG) indicates charge status. MAX1811 USB-Powered Li+ Charger ABSOLUTE MAXIMUM RATINGS IN, BATT, SELI, CHG, EN to GND ..............................-0.3V to 7V SELV to GND ...............................................-0.3V to (VIN + 0.3V) Continuous Power Dissipation (TA = +70°C) 8-Pin SO (derate 17.5mW/°C above +70°C)....................1.4W Short-Circuit Duration.................................................Continuous Operating Temperature Range ...........................-40°C to +85°C Storage Temperature Range .............................-65°C to +150°C Maximum Die Temperature..............................................+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 = 4.5V, EN = IN, TA = 0°C to +85°C, unless otherwise noted.) PARAMETER CONDITIONS Input Supply Voltage Input Undervoltage Lockout IIN rising MIN Charging Headroom Precondition Threshold MAX UNITS 6.50 V 3.75 4.05 V Input Undervoltage Lockout Hysteresis Input Supply Current TYP 4.35 50 mV Operating, EN = IN, no load 0.9 2.0 mA Shutdown, EN = GND 2.5 5.0 µA SELI = GND (100mA mode), VIN = 4.35V SELI = IN (500mA mode) BATT rising, transition from precondition to charge mode 100 mV 200 2.3 Precondition Threshold Hysteresis 2.5 2.7 80 V mV CHG Output Leakage Current VIN = V CHG = 6.5V 0.1 1.0 µA CHG Output Low Voltage ISINK = 10mA VSELI = VIN = 5.5V, VBATT = 2.7V SELI = GND, VIN = 5.5V, VBATT = 2.7V VBATT = 2V, SELI = GND or IN SELV = GND, IBATT = 0 20 4.08 0.4 500 100 70 4.12 V 455 85 43 4.10 SELV = IN, IBATT = 0 4.18 4.20 4.22 1 5 µA 2 µA Charging Current BATT Regulation Voltage BATT Leakage Current (Input Power Removed) VBATT = 4.2V, EN = IN = GND V BATT Shutdown Current EN = GND, VBATT = 4.2V Logic Input Low Voltage (EN, SELI, SELV) VIN = 4.35V to 6.5V Logic Input High Voltage (EN, SELI, SELV) VIN = 4.35V to 6.5V Logic Input Leakage Current (EN, SELI) VIN = 0 to 6.5V; VSELI, VEN = 6.5V or GND 1 µA Logic Input Leakage Current (SELV) VIN = 0 to 6.5V, VSELV = VIN or GND 1 µA Thermal Regulation Die temperature beyond which charging current is reduced 2 0.1 mA 0.8 2.0 V V 125 _______________________________________________________________________________________ °C USB-Powered Li+ Charger (VIN = 4.5V, TA = -40°C to +85°C, unless otherwise noted.) (Note1) PARAMETER CONDITIONS MIN Input Supply Voltage Input Undervoltage Lockout Precondition Threshold BATT Regulation Voltage MAX UNITS 6.50 V 3.75 4.05 V Operating, EN = IN, no load 3 mA Shutdown, EN = GND 6 µA V IIN rising Input Supply Current TYP 4.35 BATT rising, transition from precondition to charge mode 2.3 2.7 SELV = GND, IBATT = 0 4.06 4.14 SELV = IN, IBATT = 0 4.16 4.24 V BATT Leakage Current (Input Power Removed) VBATT = 4.2V, IN = GND 10 µA BATT Shutdown Current EN = GND, VBATT = 4.2V 3 µA Note 1: Specifications to -40°C are guaranteed by design and not production tested. Typical Operating Characteristics (CHG unconnected, CBATT = 2.2µF, TA = +25°C, unless otherwise noted.) SUPPLY CURRENT vs. INPUT VOLTAGE (SHUTDOWN) 0.8 3.5 0.7 450 350 VSELI = 0 0.4 IBATT (mA) 0.5 2.5 2.0 1.5 0.3 300 250 150 1.0 100 0.1 0.5 50 0 0 1 2 3 4 VIN (V) 5 6 7 VBATT = 4.1V VSELV = VIN 200 0.2 0 VSELI = VIN 400 3.0 VSELI = VIN 0.6 IIN (µA) IIN (mA) VIN = VSELV VEN = 0 4.0 500 MAX1811 toc02 VIN = VEN = VSELV 0.9 4.5 MAX1811 toc01 1.0 CHARGE CURRENT vs. INPUT VOLTAGE HEADROOM MAX1811 toc03 SUPPLY CURRENT vs. INPUT VOLTAGE (ENABLED) VSELI = 0 0 0 1 2 3 4 VIN (V) 5 6 7 0 0.5 1.0 1.5 2.0 2.5 3.0 VIN - VBATT (V) _______________________________________________________________________________________ 3 MAX1811 ELECTRICAL CHARACTERISTICS Typical Operating Characteristics (continued) (CHG unconnected, CBATT = 2.2µF, TA = +25°C, unless otherwise noted.) CHARGE CURENT vs. INPUT VOLTAGE VSELI = VIN IBATT (mA) 250 200 VSELI = 0 300 VSELI = VIN 250 VSELI = 0 200 150 100 50 100 0 50 -50 0 0 1 2 3 4 5 6 -15 10 35 TEMPERATURE (°C) MAX1811 toc07 600 VIN = VSELV = VEN = 6.5V, VBATT = 2.7V 500 VSELI = VIN VSELI = VIN 400 IBATT (mA) IBATT (mA) -40 CHARGE CURRENT vs. TEMPERATURE WITH THERMAL REGULATION 500 300 200 300 200 VSELI = 0 THERMAL CONTROL LOOP IN OPERATION VSELI = 0 100 0 0 -40 -15 10 35 TEMPERATURE (°C) 4 7 VIN (V) VIN = VSELV = VEN = 5.5V, VBATT = 2.7V 100 VSELV = 0 4.08 CHARGE CURRENT vs. TEMPERATURE 400 4.14 4.10 VBATT (V) 600 VIN = VSELI = VEN = 4.5V IBATT = 0 4.16 4.12 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 VSELV = VIN 4.18 350 300 150 4.20 VBATT (V) 350 400 MAX1811 toc08 400 VBATT = 4.1V VSELV = VIN 450 4.22 MAX1811 toc05 VIN = VEN = VSELV = 5.5V 450 500 MAX1811 toc04 500 BATTERY REGULATION VOLTAGE vs. TEMPERATURE MAX1811 toc06 CHARGE CURRENT vs. BATTERY CURRENT IBATT (mA) MAX1811 USB-Powered Li+ Charger 60 85 -40 -15 10 35 60 85 TEMPERATURE (°C) _______________________________________________________________________________________ 60 85 USB-Powered Li+ Charger PIN NAME DESCRIPTION 1 SELV Battery Regulation Voltage-Select Input. A low (< 0.8V) selects a 4.1V battery regulation set point. A high (> 2.0V) selects a 4.2V battery regulation set point. 2 SELI Battery Regulation Current-Select Input. A low (< 0.8V) selects a 100mA maximum battery regulation current. A high (> 2.0V) selects a 500mA maximum battery regulation current. SELI is not diode clamped to IN, and the voltage at VSELI can exceed the voltage at VIN. 3, 6 GND Ground. Connect pins 3 and 6 to a large copper trace for maximum power dissipation. 4 IN 5 BATT 7 EN 8 CHG Input Supply Voltage. Bypass with a 4.7µF capacitor to GND. Li+ Battery Connection. Bypass with a capacitor no less than 2.2µF to GND. High impedance in shutdown. Enable Input. A high (> 2.0V) enables the device. A low (< 0.8V) disables the device and places it into shutdown mode. BATT is high impedance when disabled. Charging Indicator Open-Drain Output. CHG pulls low while the device is in charge mode (2.5V < VBATT < BATT Regulation Voltage). IN SELI VOLTAGE LOOP CURRENT SELECTOR REGULATOR BATT THERMAL LOOP 3V CHG EN VOLTAGE SELECTOR BIAS OVERCURRENT DETECTOR (2.5V, 4.2V) 4.7V BATTERY OVERVOLTAGE DETECTOR 2V MAX DETECTOR CIRCUIT CURRENT LOOP MAX1811 CURRENTSENSE CIRCUIT SELV GND Figure 1. Functional Diagram _______________________________________________________________________________________ 5 MAX1811 Pin Description MAX1811 USB-Powered Li+ Charger Detailed Description Charger-Control Circuitry The voltage/current regulator consists of a voltage control loop, a current control loop, and a thermal control loop (Figure 1). Use the SELV input to set the battery regulation voltage to a 4.1V or 4.2V single Li+ cell. The current and thermal loops are internally compensated and require no external compensation. The outputs from all loops drive an internal linear regulator. The thermal loop modulates the current loop by limiting the charge current if the die temperature exceeds +125°C. The MAX1811 is in current mode when the BATT voltage is below the regulation set point and in voltage mode when the BATT voltage is near the regulation set point. The CHG output indicates whether the part is in current mode (CHG = low) or voltage mode (CHG = high impedance). Battery voltages less than 2.5V activate a 43mA preconditioning mode (CHG = high impedance). Normal charging resumes when the battery voltage exceeds 2.5V. System Configuration The MAX1811 is designed to operate seamlessly with a universal serial bus (USB) port. In a typical design, the USB connects to the MAX1811 input, and the MAX1811 drives the load and charges the battery when enabled. Charge-Current Selection The MAX1811 charges a single cell Li+ battery in either 100mA or 500mA modes. The MAX1811 expects the system to poll the USB host to determine if the USB is capable of providing 100mA or 500mA and regulates the charging current accordingly (Figure 2). This is to maintain compatibility with both powered and unpowered USB hosts. A powered USB host is capable of USB* PORT BATT IN MAX1811 4.35V TO 5.5V SINGLE Li+ CELL providing 500mA, and an unpowered USB hub is limited to only 100mA. Drive SELI low to set the charge current to the 100mA mode. Use a 10kΩ pulldown resistor to ground on SELI, if necessary, to ensure that the MAX1811 defaults to the 100mA mode in the event that no logic signal is present. Drive SELI high to increase the charge current to the 500mA mode only if the polled USB port can provide the required current. Thermal-Control Circuitry The thermal loop limits the MAX1811 die temperature to +125°C by reducing the charging current as necessary. The MAX1811 can operate normally with the thermal loop active. This is not a fault condition and can be used continuously. The power dissipated by the internal power FET is determined by (VIN - VBATT) ✕ ICHG. The power dissipation rating for the thermally enhanced 8-pin SO package is 1.4W at +50°C ambient (assuming a 1in2 PC board radiating area), which is the maximum ambient temperature at which most Li+ battery manufacturers allow charging. The 1.4W power dissipation may never be reached due to the MAX1811’s thermal regulation loop. Applications Information USB Output Voltage The minimum voltage to a USB-powered device may be as low as 4.35V when cable and connector drops are considered (Figure 3). The MAX1811 is optimized for operation at these low input voltage levels. USB hubs may also provide as much as 5.5V. At high input voltages (5.5V) and low cell voltages (2.7V), the MAX1811’s thermal loop may limit the charge current until the cell voltage rises. SYSTEM LOAD *WHEN USING WALL ADAPTER, IN VOLTAGE RANGE IS FROM 4.35V TO 6.5V. Figure 2. System Configuration 6 _______________________________________________________________________________________ USB-Powered Li+ Charger Capacitor Selection Use a larger input bypass capacitor for high input voltages or high charging current to reduce supply noise. Chip Information TRANSISTOR COUNT: 1907 PROCESS: BiCMOS Use a minimum of 2.2µF placed close to BATT for proper stability. Bypass IN to GND with a 4.7µF capacitor. HOST OR POWERED HUB 4.750V LOW-POWER FUNCTION BUS-POWERED HUB 4.735V 4.640V 4.625V *4.400V 4.397V 4.375V 4.378V 4.500V 0.000V 0.015V 0.110V 0.125V 4.350V 0.000V 0.003V 0.002V 0.025V REFERENCED REFERENCED TO SOURCE TO HUB *UNDER TRANSIENT CONDITIONS, SUPPLY AT HUB CAN DROP FROM 4.00V TO 4.070V. Figure 3. USB Voltage Specification TO LOAD BATT 4.35V TO 6.5V SINGLE Li+ CELL IN 4.2V SELV 4.1V ON TO IN MAX1811 LED EN OFF CHG 500mA SELI 100mA GND GND CHG LOGIC OUT 10kΩ Figure 4. Charging from a USB Port _______________________________________________________________________________________ 7 MAX1811 Charging from AC Adapters The MAX1811 also operates from sources other than USB ports. The full charging input voltage range is 4.35V to 6.5V. When charging in the 500mA mode with an AC adapter, rely on the thermal loop to limit the power dissipation by limiting the charge current at higher input voltages if limited PC board area is available to dissipate heat. 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.) DIM A A1 B C e E H L N H E INCHES MILLIMETERS MAX MIN 0.069 0.053 0.010 0.004 0.019 0.014 0.010 0.007 0.050 BSC 0.157 0.150 0.228 0.244 0.050 0.016 MAX MIN 1.35 1.75 0.10 0.25 0.35 0.49 0.19 0.25 1.27 BSC 3.80 4.00 5.80 6.20 0.40 SOICN .EPS MAX1811 USB-Powered Li+ Charger 1.27 VARIATIONS: 1 INCHES TOP VIEW DIM D D D MIN 0.189 0.337 0.386 MAX 0.197 0.344 0.394 MILLIMETERS MIN 4.80 8.55 9.80 MAX 5.00 8.75 10.00 N MS012 8 AA 14 AB 16 AC D C A B e 0 -8 A1 L FRONT VIEW SIDE VIEW PROPRIETARY INFORMATION TITLE: PACKAGE OUTLINE, .150" SOIC APPROVAL DOCUMENT CONTROL NO. 21-0041 REV. B 1 1 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. 8 _____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 © 2003 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.