Features: `96% Efficiency
`Small, 16-Pin QSOP Package (half the size of a 16-pin narrow SO)
`Pin-Compatible with MAX797 (MAX1653/MAX1655)
`Output Voltage Down to 1V (MAX1655)
`4.5V to 30V Input Range
`99% Duty Cycle for Lower Dropout
`170A Quiescent Supply Current
`3A Logic-Controlled Shutdown
`Dual, N-Channel, Synchronous-Rectified Control
`Fixed 150kHz/300kHz PWM Switching,or Synchronized from 190kHz to 340kHz
`Programmable Soft Start
`Low-Cost Secondary Outputs (MAX1652/MAX1654)Application·Notebook Computers
·PDAs
·Cellular Phones
·Hand-Held Computers
·Handy-Terminals
·Mobile Communicators
·Distributed PowerPinout
SpecificationsV+ to GND .........................................................-0.3V to +36V
GND to PGND ...................................................-0.3V to +0.3V
VL to GND ...........................................................-0.3V to +6V
BST to GND........................................................-0.3V to +36V
DH to LX ................................................-0.3V to (BST + 0.3V)
LX to BST............................................................-6V to +0.3V
SHDN to GND...........................................-0.3V to (V+ + 0.3V)
SYNC, SS, REF, SECFB, SKIP, FB to GND...-0.3V to (VL + 0.3V)
DL to PGND .............................................-0.3V to (VL + 0.3V)
CSH, CSL to GND ...............................................-0.3V to +6V
VL Short Circuit to GND........................................Momentary
REF Short Circuit to GND .....................................Continuous
VL Output Current ........................................+50mA to -1mA
REF Output Current.........................................+5mA to -1mA
Continuous Power Dissipation (TA = +70°C)
SO (derate 8.70mW/°C above +70°C) ..................696mW
QSOP (derate 8.3mW/°C above +70°C) ................667mW
Operating Temperature Range
MAX165_E_E .............................................-40°C to +85°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.
DescriptionThe MAX1654 are high-efficiency, pulsewidth-modulated (PWM), step-down DC-DC controllers in small QSOP packages. The MAX1653/MAX1655 also come in 16-pin narrow SO packages that are pincompatible upgrades to the popular MAX797. Improvements include higher duty-cycle operation for better dropout, lower quiescent supply currents for better light-load efficiency, and an output voltage down to 1V (MAX1655).
The MAX1652MAX1655 achieve up to 96% efficiency and deliver up to 10A using a unique Idle Mode™ synchronous-rectified PWM control scheme. These devices automatically switch between PWM operation at heavy loads and pulse-frequency-modulated (PFM) operation at light loads to optimize efficiency over the entire output current range. The MAX1653/MAX1655 also feature logic-controlled, forced PWM operation for noise-sensitive applications.
All devices operate with a selectable 150kHz/300kHz switching frequency, which can also be synchronized to an external clock signal. Both external power switches are inexpensive N-channel MOSFETs, which provide low resistance while saving space and reducing cost.
The MAX1652 and MAX1654 have an additional feedback pin that permits regulation of a low-cost second output tapped from a transformer winding. The MAX1652 provides an additional positive output. The MAX1654 provides an additional negative output.
The MAX1652MAX1655 have a 4.5V to 30V input voltage range. The MAX1652/MAX1653/MAX1654's output range is 2.5V to 5.5V while the MAX1655's output range extends down to 1V. An evaluation kit (MAX1653EVKIT) is available to speed designs.
MAX1654 Data Sheet
