1.5MHz, 25V Dual Step-Down DC/DC ConverterDelivers 3A per Channel from a TSSOP-20E Package

Linear Technology announces the LT3501, a dual current mode PWM step-down DC/DC converter with two internal 3.5A power switches packaged in a 20-lead TSSOP-20E package. Each channel is capable of delivering up to 3A of continuous output current at efficiencies up to 88%. Independent input voltage, feedback, soft-start and power good pins for each channel simplify complex power supply tracking and sequencing requirements. Its wide input range of 3.3V to 25V makes it ideal for regulating power from a wide variety of sources, including 5V and 12V rails, unregulated wall transformers, lead acid batteries and distributed power supplies. The LT3501's switching frequency is user programmable between 250kHz and 1.5MHz, allowing optimization between efficiency and external component size.

Both of the LT3501's converters are synchronized to an external clock input or an internal oscillator and maintain a 180 degree phase offset between channels to reduce voltage ripple and input capacitor size. An internal 0.80V reference enables sub 1V output voltages required to power the latest generation of low voltage DSPs and microcontrollers. Independent, sequential, ratiometric or absolute tracking is easily attained between the outputs. Low drop-out internal switches enable duty cycles to reach 95% while internal cycle-by-cycle current limit provides protection against shorted outputs. The low current (<10uA) shutdown offers extended run-time in battery-powered systems.

The LT3501EFE is available from stock in a thermally enhanced TSSOP-20 package. There is also an "I" Grade temperature version, the LT3501IFE. Pricing starts at $3.50 and $4.20 each, respectively, for 1,000-piece quantities.

Summary of Features: LT3501
Wide Input Range: 3.3V to 25V
Two Switching Regulators with 3A Output Capability
Independent Supply to Each Regulator
Adjustable/Synchronizable Fixed Frequency Operation from 250kHz to 1.5MHz
Antiphase Switching
Outputs Can Be Paralleled
Independent, Sequential, Ratiometric or Absolute Tracking Between Outputs
Independent Soft-Start and Power Good Pins
Enhanced Short-Circuit Protection

Low Dropout: 95% Maximum Duty Cycle
Low Shutdown Current: <10uA
20-Lead TSSOP Package with Exposed Leadframe