EVALUATION KIT AVAILABLE High-Efficiency, White LED MAX8831 2 Step-Up Converter with I C Interface in 2mm x 2mm WLP General Description Benefits and Features The MAX8831 integrates a 60mA, 28V PWM DC-DC Highly Integrated 28V Step-Up DC-DC Converter with step-up converter with five low-dropout LED current Programmable Functionality Lowers System Cost regulators for display and keypad backlighting in cell Integrated NMOS Power Switch phones, PDAs, and other portable devices. The IC pro- Two 25mA Regulators for Display Backlighting vides up to 90% efficiency over the entire input voltage 2 I C-Programmable 50A to 25.25mA Output Current range of 2.7V to 5.5V. The step-up converter operates 128-Step Logarithmic Dimming at a fixed 2MHz switching frequency, enabling the use Individually Programmable Ramp (Up/Down) Timers of very small external components to achieve a com- Low Dropout (200mV max) pact circuit area. For improved efficiency, the step-up Three 5mA Current Regulators for Keypad Lighting converter automatically transitions to pulse-skipping 2 mode at light loads. with I C-Programmable 50A to 5.0mA Output Current 32-Step Logarithmic Dimming Each of the five current regulators accommodates up to Individually Programmable Ramp (Up/Down) Timers 9 series LEDs (depending on LED string forward volt- 2 Individual Blink Rate and Duty Cycle Timers age), and is independently programmed using an I C Low Dropout (150mV max) interface. Two of the current regulators (LED1, LED2) 2 I C Programmable Compatible with 1.8V Logic are intended to support display backlight functions and are programmable up to 25mA using a 128-step loga- Protection Features Increase Reliability rithmic dimming scheme. The other three regulators Open/Short LED and Open-Circuit Diode Detection (LED3, LED4, LED5) are suitable for keyboard backlight Thermal-Shutdown and Output Overvoltage functions or for driving signal indicators, and are pro- Protection grammable up to 5mA using a 32-step logarithmic dim- High Efficiency and Low Shutdown Current Extend ming scheme. The low-current regulators (LED3, LED4, Battery Life LED5) can be operated from the step-up converter or > 90% Efficiency from a separate low-voltage source. Pulse Skipping for Improved Light-Load Efficiency 2 The I C interface controls all operational aspects of the Ultra-Low 0.1A Shutdown Current current regulators, including: on/off state, LED current, Small Solution Size Saves Board Space ramp-up/ramp-down timers, and blink rate timers Tiny 2mm x 2mm, 16-Bump WLP Package (LED3, LED4, LED5). The MAX8831 write/read address- 2MHz Switching Frequency Allows Use of Tiny es are factory programmed at 0x9A/0x9B (contact the External Components factory for other address options). The MAX8831 features open/short LED fault detection, output overvoltage protection, thermal shutdown, and Ordering Information open-circuit Schottky diode detection, with the status of PART TEMP RANGE PIN-PACKAGE each fault monitored continually for readback through 2 the I C interface. 16 WLP MAX8831EWE+T -40C to +85C 2mm x 2mm The MAX8831 is available in a tiny 2mm x 2mm, 16-bump WLP package. +Denotes a lead(Pb)-free/RoHS-compliant package. T = Tape and reel. Applications Cell Phones PDAs Smartphones 19-4370 Rev 2 5/15High-Efficiency, White LED MAX8831 2 Step-Up Converter with I C Interface in 2mm x 2mm WLP Absolute Maximum Ratings IN to GND..............................................................-0.3V to +6.0V Continuous Power Dissipation (T = +70C) A V , COMP to GND.....................................-0.3V to (V + 0.3V) 16-Bump, 2mm x 2mm WLP DD IN SDA, SCL to GND.......................................-0.3V to (V + 0.3V) (derate 8.2mW/C above +70C ambient)...................660mW DD OUT, LX, LED1LED5 to GND................................-0.3V to +30V Junction Temperature......................................................+150C I (Note 1) .....................................................................1.2A Storage Temperature Range .............................-65C to +150C LX RMS PGND to GND .......................................................-0.3V to +0.3V Bump Temperature (soldering, reflow)............................+260C Operating Temperature Range ...........................-40C to +85C Note 1: LX has an internal clamp diode to PGND. Applications that forward bias this diode should take care not to exceed the power dissipation limits of the device. 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 = 3.6V, V = V = 0V, V = 1.8V, T = -40C to +85C, unless otherwise noted. Typical values are at T = +25C.) (Note 1) IN GND PGND DD A A PARAMETER CONDITIONS MIN TYP MAX UNITS IN Supply Voltage 2.7 5.5 V V Supply Voltage 1.6 5.5 V DD IN Undervoltage Lockout 2.4 2.6 V Threshold IN Quiescent Current No load, 2MHz switching 1.5 mA T = +25C 0.1 1 A IN Shutdown Current V = GND A DD T = +85C 0.1 A T = +25C 0.1 1 A V Standby Current V = V = V A DD SDA SCL DD T = +85C 0.1 A T = +25C 2 5 A IN Standby Current V = V = V A SDA SCL DD T = +85C 2 A T = +25C 0.01 1 A OUT Leakage Current V = V = 5.5V, V = GND A IN OUT DD T = +85C 0.1 A LED CURRENT REGULATORS I or I = 25mA setting 200 mV LED Current Regulator Dropout LED1 LED2 Voltage (Note 2) I or I or I = 5.0mA setting 150 mV LED3 LED4 LED5 T = +25C -2 +2 A I or I = 25.25mA LED1 LED2 % setting T = -40C to +85C -5 +5 A LED Current Accuracy T = +25C -2 +2 A I or I or I = 5.0mA LED3 LED4 LED5 % setting T = -40C to +85C -5 +5 A T = +25C 0.01 1 A LED Leakage Current V = 5.5V, V = GND A LED DD T = +85C 0.1 A LED Regulation Voltage 0.35 V N-CHANNEL SWITCH LX Current Limit 780 860 mA LX On-Resistance I = 200mA 0.3 LX www.maximintegrated.com Maxim Integrated 2