MAX8857AETL+

ABRIDGED 19-0987; Rev 1; 2/12 KIT ATION EVALU E L B AVAILA Smallest, All-Internal MOSFET, 7-Channel 2 AA DSC PMIC The MAX8857A PMIC provides a complete power-supply solution for digital still cameras (DSCs) and digital video cameras (DVCs). The MAX8857A improves performance, component count, and board space utilization compared to currently available solutions for 2 AA cell and dual-battery designs. On-chip power MOSFETs provide up to 95% efficiency for critical power supplies. The CCD inverter can operate directly from 2 AA/NiMH batteries without the use of any additional external components. • Step-up synchronous-rectified DC-DC converter (SU). The MAX8857A is bootstrapped from VSU. • MAIN synchronous-rectified step-up DC-DC converter (M) with active discharge for DSP I/O supply voltage. • SDZ synchronous-rectified step-down DC-DC converter (Z) for DSP DDR supply voltage. • Low-voltage (down to 1V) synchronous-rectified step-down DC-DC converter (SD) for DSP core supply voltage. • Step-up DC-DC converter with current regulation and PWM dimming control (LEDBST) for up to 6 series white LEDs (WLED). • High-voltage step-up DC-DC converter (CCDBST) for CCD imagers or positive LCD bias supplies. • Transformerless inverting DC-DC converter (CCDINV) for CCD imagers or negative LCD bias supplies. This converter can connect directly to 2 AA batteries. The MAX8857A has an independent/simultaneous power-on sequence of the CCDBST and CCDINV converters. For a preset power-on sequence of CCDBST before CCDINV, contact the factory. The MAX8857A is available in a 5mm x 5mm, 40-pin thin QFN package and operates over the -40°C to +85°C extended temperature range. Applications DSCs and DVCs PDAs and Portable Media Players TEMP RANGE PIN-PACKAGE MAX8857AETL+ -40°C to +85°C 40 Thin QFN-EP* 5mm x 5mm x 0.8mm o 95% Efficient Synchronous-Rectified DC-DC Converters o 90% Efficient Boost-Buck Operation o Up to 85% Efficient, High-Voltage DC-DC Converters o Inverter Operates Directly from 2 AA Batteries o o o o o Internal Compensation on All Channels True Shutdown™ on All Step-Up Converters Overload Protection Startup into Short Protection Soft-Start for Controlled Startup Current o 100% Duty Cycle on Step-Down Converters o o o o Regulated Current Output for Up to 6 White LEDs PWM Dimming of WLED Current Adjustable LED Overvoltage Protection Up to 27V Transformerless Inverting Converter for CCD o 2MHz ±2.5% Switching Frequency o 1µA Shutdown Supply Current o CCD Voltage Sequencing o All Internal Power MOSFETs o SDOK Power-OK Indicator Typical Operating Circuit INPUT 1.8V TO 5.5V PVBST ONSU PKG CODE T4055-2 MAX8857AETL+ -40°C to 40 Thin QFN-EP* T4055-2 TCBR +85°C 5mm x 5mm x 0.8mm +Denotes a lead-free package. *EP = Exposed paddle. Note: Contact factory for the option where CCDBST must reach regulation before the INV converter can be turned on. SU STEP-UP MAIN STEP-UP ONM SD STEP-DOWN ONSD SDZ STEP-DOWN ONZ Ordering Information PART Features VSU 5V VMAIN 3.3V VSD 1.8V VDDRZ 2.5V MAX8857A SDOK ONLED LEDBST VLEDBST UP TO 6 WLEDs ONBST CCDBST VCCDBST +15V ONINV CCDINV VCCDINV -7.5V Pin Configuration appears at the end of data sheet. True Shutdown is a trademark of Maxim Integrated Products, Inc. ________________________________________________________________ Maxim Integrated Products 1 For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com. MAX8857A General Description ABRIDGED MAX8857A Smallest, All-Internal MOSFET, 7-Channel 2 AA DSC PMIC VREF C20 0.1µF 24 REF VBATT (1.8V TO 5.5V) C1 22µF C2 22µF FBINV PVSU 30 PVSU C3 22µF C4 22µF R17 100Ω R1 402kΩ C21 0.1µF SWBST SU R14 100kΩ L6 2.2µH LXBST FBSU FBBST VBATT L2 1µH VMAIN (3.3V, 300mA) PVBST C7 22µF VBATT C8 10µF 34 L3 4.7µH VSD (1.8V, 250mA) C10 10µF PVLED SWLED 3 R4 10kΩ FBM PGM (EP) PVSD 7 R6 100kΩ VBATT 28 VSU 4 NOTE 2: ALL CONVERTERS’ POWER GROUND CONNECTIONS ARE THROUGH THE EXPOSED PADDLE (EP). LXLED OVLED PVGD FBLED 35 LXSD C9 10µF NOTE 1: ALL ON_ PINS HAVE INTERNAL 1MΩ PULLDOWN TO GROUND. VCCDBST (15V, 30mA) C17 2.2µF 33 12 21 8 38 FBSD PGSD (EP) VBATT C16 1µF VBATT C14 1µF 18 13 14 L5 4.7µH GND PVZ LXZ C15 3.3µF 11 ONZ R9 1.6MΩ FBZ PGZ (EP) SDOK D6 VSU C23 1µF, OPTIONAL D5 R10 100kΩ 19 D4 9 R15 10Ω 25 VSU C11 1µF 36 37 L4 4.7µH VDDRZ (2.5V, 200mA) C13 10µF R7 150kΩ 5 6 R8 100kΩ R16 100kΩ VBATT Figure 1. MAX8857A Typical Application Circuit 14 D7 10 C12 10µF ONLED ONINV VLEDBST (16V, 25mA) D1 ONSD ONBST R12 100kΩ PGLED (EP) EP ONSU ONM R11 1.4MΩ 22 LXM 1, 2 PVM C6 22µF VREF D2 20 PGSU (EP) 39, 40 R13 604kΩ 23 PGBST (EP) 27 C5 1µF C19 10µF 17 MAX8857A 26 R2 100kΩ VCCDINV (-7.5V, 100mA) D3 LXSU LXSU 29 VSU (5V, 500mA) C18 1µF L7 10µH 31 R5 80.6kΩ 16 PVINV 15 LXINV L1 2µH 32 R3 23.2kΩ VBATT ______________________________________________________________________________________