LTC1704

` Dual Regulated Outputs: One Switching Regulator and One Linear Regulator
` Excellent DC Accuracy: ±1.5% for Switcher and ±2% for Linear Regulator
` External N-Channel MOSFET Architecture
` No External Current Sense Resistor Required
` Burst Mode<sup>®</sup> Operation at Light Load (LTC1704)
` Continuous Switching at Light Load (LTC1704B)
` Linear Regulator with Programmable Current Limit
` Linear Regulator with Programmable Start-Up Delay
` Low Shutdown Current: <150A
` High Efficiency Over Wide Load Current Range
` PGOOD Flag Monitors Both Outputs
` Small 16-Pin Narrow SSOP Package

· Multiple Logic Supply Generator
· Distributed Power Applications
· High Efficiency Power Conversion

Supply Voltage
   V_CC, PV_CC ........................................................... 6V
   BOOST........................................................................ 12V
   BOOST SW .............................................................. 6V
Input Voltage
   SW ................................................................. 1V to 6V
   FB, REGFB, REGILM,
   RUN/SS, I_MAX .................................0.3V to (V_CC + 0.3V)
Peak Output Current <10s
   TG, BG (Note 7) ........................................................... 5A
Operating Temperature Range (Note 2) .. 40°C to 85°C
Storage Temperature Range ................. 65°C to 150°C
Lead Temperature (Soldering, 10 sec)..................... 300°C

The LTC^®1704/LTC1704B include a high power synchronous switching regulator controller plus a linear regulator controller. The switching regulator controller is designed to drive a pair of N-channel MOSFETs in a voltage mode, synchronous buck configuration to provide the main supply. The constant frequency, true PWM architecture switches at 550kHz, minimizing external component size, cost and optimizing load transient performance. The LTC1704 features automatic transition to power saving Burst Mode operation at light loads. The LTC1704B does not shift into Burst Mode operation at light loads, eliminating low frequency output ripple at the expense of light load efficiency. The linear regulator controller is designed to drive an external NPN power transistor to provide up to 2A of current to an auxiliary load.

The LTC1704/LTC1704B deliver better than ±1.5% DC accuracy at the switcher outputs and ±2% at the linear regulator outputs. High performance feedback loops allow the circuit to keep total output regulation within ±5% under all transient conditions. An open-drain PGOOD output indicates when both outputs are within ±10% of their regulated values.