EVALUATION KIT AVAILABLE Highest Efficiency Supply MAX8901A/MAX8901B for 2 to 6 Series WLEDs in a 2mm x 2mm TDFN Package General Description Benefits and Features The MAX8901A/MAX8901B step-up converters drive Cost-Effective and Flexible Solution for Wide Range of from two to six series-connected white LEDs (WLEDs) Backlighting Applications with constant current to provide uniform WLED intensity Supplies from 2 to 6 WLEDs with 1.3% LED Current for LCD backlighting in cell phones, PDAs, and other Accuracy handheld devices. The MAX8901 operate at a fixed 2.6V to 5.5V Input Voltage Range 750kHz (typ) switching frequency, allowing for tiny exter- Fixed-Frequency Operation nal components, and are optimized for the highest possi- Flexible Dimming Control ble efficiency over the full 1-cell Li+/Li-Poly battery range. Direct PWM Dimming (MAX8901A) These converters use a single input (ON) to enable the 32-Step, Single-Wire Serial Dimming (MAX8901B) IC and to control WLED intensity. The MAX8901A Protection Features Improve System Reliability requires a direct PWM input to regulate WLED intensity WLED Overvoltage Protection (25V typ) with the WLED current proportional to the PWM duty Internal Soft-Start and Thermal Shutdown cycle. The MAX8901B uses single-wire, serial-pulse Input Undervoltage Lockout dimming that reduces the WLED intensity in 32 linear Input Overvoltage Lockout steps. Full-scale WLED current for serial-pulse dimming is 24.75mA (MAX8901B, 0.75mA/step). High Efficiency Extends Battery Life Up to 91% Efficiency The MAX8901 feature an internal soft-start to eliminate 0.01A (typ) Shutdown Current inrush currents during startup, input overvoltage No WLED Current in Shutdown protection, WLED overvoltage protection, and a shut- down mode with 0.01A (typ) shutdown current. No 8-Pin, 2mm x 2mm TDFN Package Saves Space WLED current is present in shutdown provided the WLED forward voltage is greater than the input supply Ordering Information voltage. Additional features include undervoltage lock- out (UVLO) and thermal shutdown. PART PIN-PACKAGE TOP MARK The MAX8901 are available in tiny 8-pin, 2mm x 2mm 8 TDFN-EP* MAX8901AETA+T +ABA TDFN-EP packages (0.8mm max height). 2mm x 2mm 8 TDFN-EP* Applications MAX8901BETA+T +ABB 2mm x 2mm Display Backlight (from 2 to 6 WLEDs) Note: All devices are specified over the -40C to +85C operating Cellular Phones temperature range. +Denotes a lead(Pb)-free/RoHS-compliant package. PDAs and Smartphones *EP = Exposed pad. MP3 and Portable Media Players T = Tape and reel. Portable Navigation Devices Pin Configuration appears at end of data sheet. Digital Cameras Typical Operating Circuits INPUT INPUT 2.6V TO 5.5V 2.6V TO 5.5V OUTPUT OUTPUT UP TO 25V UP TO 25V 3 4 3 4 LX LX IN IN MAX8901A MAX8901B 7 1 1 7 COMP OVP COMP OVP 6 GND SERIAL-PULSE 6 5 5 GND PWM DIMMING PGND DIMMING PGND CONTROL CONTROL 2 2 8 8 ON ON CS CS EP EP 19-0865 Rev 4 5/15Highest Efficiency Supply MAX8901A/MAX8901B for 2 to 6 Series WLEDs in a 2mm x 2mm TDFN Package Absolute Maximum Ratings IN to GND.................................................................-0.3V to +7V Operating Temperature Range ...........................-40C to +85C CS, COMP, ON to GND ...............................-0.3V to (V + 0.3V) Junction Temperature......................................................+150C IN OVP, LX to GND .....................................................-0.3V to +28V Storage Temperature Range .............................-65C to +150C PGND to GND .......................................................-0.3V to +0.3V Lead Temperature (soldering, 10s) .................................+300C LX Current ..................................................................770mA Soldering Temperature (reflow) .......................................+260C RMS Continuous Power Dissipation (multilayer board at +70C) 8-pin, 2mm x 2mm TDFN (derate above +70C by 11.9mW/C)..........................953mW 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 = V = V = 3.6V, V = V = 0V, COMP, CS, and LX are unconnected, T = -40C to +85C, unless otherwise noted. IN ON OVP PGND GND A Typical values are at T = +25C.) (Note 1) A PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS Input Voltage V 2.6 5.5 V IN V rising 2.25 2.55 Input Undervoltage Lockout IN V V IN UVLO Threshold V falling 2.53 IN V rising 6.2 6.35 Input Overvoltage Lockout IN V V IN OVLO Threshold V falling 6.0 6.3 IN T = +25C 0.01 1 A Shutdown Input Current I V = 0V A SHDN ON T = +85C 0.1 A MAX8901A 70 135 V = 0.55V, no load CS Quiescent Current I A Q (not switching) MAX8901B 115 185 V - IN Output Voltage Range V V = external boost diode voltage drop V V OUT DIODE OV V DIODE OVP Overvoltage Protection V 6 LEDs with 25V OVP option 24 25 26 V OV Threshold OVP Input Current I V = 20V 20 A OV OVP CS Regulation Voltage V No dimming 0.475 0.50 0.525 V CS Time V is below low threshold until ON ON Shutdown Delay t 1.18 1.33 1.50 ms SHDN shutdown (Figure 1) ON High Voltage V 2.6V < V < 5.5V 1.3 V ON HI IN ON Low Voltage V 2.6V < V < 5.5V 0.4 V ON LO IN T = +25C 0.01 1 A ON Input Current I ON = IN A ON T = +85C 0.1 A First ON high pulse to enable IC Initial ON High Pulse Width t 40 s HI INIT (MAX8901B) (Figure 1) ON High Pulse Width t MAX8901B (Figure 1) 0.5 s HI ON Low Pulse Width t MAX8901B (Figure 1) 0.5 500.0 s LO www.maximintegrated.com Maxim Integrated 2