MAX746

93% to 96% Efficiency for 50mA to 3A Output Currents
4V to 15V Input Voltage Range
Low 950A Supply Current
1.4A Shutdown Current
Drives External N-Channel FETs
Fixed-Frequency Current-Mode PWM (Heavy Loads)
Idle-Mode PFM (Light Loads)
Cycle-by-Cycle Current Limiting
2V ±1.5% Accurate Reference Output
Adjustable Soft-Start
Undervoltage Lockout
Precision Comparator for Power-Fail or Low-Battery Warning

5V-to-3.3V Green PC Applications Notebook/Laptop Computers Personal Digital Assistants Battery-Operated Equipment Cellular Phones

Supply Voltage V+, AV+ to GND ........................................................-0.3V to 17V
HIGH, EXT to GND..............................................................................-0.3V to 21V
AGND to GND....................................................................................-0.3V to 0.3V
All Other Pins.........................................................................-0.3V to (V+ + 0.3V)
Reference Current (IREF) ...........................................................................±2mA
Continuous Power Dissipation (TA = +70°C)
Plastic DIP (derate 10.53mW/°C above +70°C) ....................................842mW
Narrow SO (derate 8.70mW/°C above +70°C) ......................................696mW
CERDIP (derate 10.00mW/°C above +70°C)..........................................800mW
Operating Temperature Ranges:
MAX746C_E...................................................................................0°C to +70°C
MAX746E_E ...............................................................................-40°C to +85°C
MAX746MJE .............................................................................-55°C to +125°C
Junction Temperatures:
MAX746C_E/E_E......................................................................................+150°C
MAX746MJE..............................................................................................+175°C
Storage Temperature Range ...................................................-65°C to +160°C
Lead Temperature (soldering, 10sec) .....................................................+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.

The MAX746 is a high-efficiency, high-current, step-down DC-DC power-supply controller that drives external N-channel FETs. It provides 93% to 96% efficiency from a 6V supply voltage with load currents ranging from 50mA up to 3A. It uses a pulse-width-modulating (PWM) current-mode control scheme to provide precise output regulation and low output noise. The MAX746's 4V to 15V input voltage range, fixed 5V/adjustable (Dual-ModeTM) output, and adjustable current limit make this device ideal for a wide range of applications.

High efficiency of MAX746 is maintained with light loads due to a proprietary automatic pulse-skipping control (Idle-ModeTM) scheme that minimizes switching losses by reducing the switching frequency at light loads. The low 950A quiescent current and ultra-low 1.4A shutdown current further extend battery life.

External components are protected by the MAX746's cycleby- cycle current limit. The MAX746 also features a 2V ±1.5% reference, a comparator for low-battery detection or level translating, and soft-start and shutdown capability.

The MAX747-discussed in a separate data sheet- functions similarly to the MAX746, but drives P-channel logic level FETs.