Switching Power Supply with Linear Regulators

The 33997 is a medium-power, multi-output power supply integrated circuit that is capable of operating over a wide input voltage range, from 6.0 V up to 26.5 V with 40 V transient capability. It incorporates a sensorless current mode control step-down switching controller regulating directly to 5.0 V. The 3.3 V linear regulator uses an external pass transistor to reduce the 33997 power dissipation. The 33997 also provides a 3.3 V linear standby regulator and two 5.0 V sensor supply outputs protected by internal low-resistance LDMOS transistors.

Features

• Operating Voltage Range 6.0 V up to 26.5 V (40 V transient)

• Step-Down Switching Regulator Output VDDH = 5.0 V @ 1400 mA (total)

• Linear Regulator with External Pass Transistor VDDL = 3.3 V @ 400 mA

• Low-Power Standby Linear Regulator VKAM = 3.3 V @ 10 mA

• Two 5.0 V @ 200 mA (typical) Sensor Supplies VREF Protected Against

Short-to-Battery and Short-to-Ground with Retry Capability

• Undervoltage Shutdown on the VDDL, VDDH Outputs with Retry Capability

• Reset Signals

• Power-Up Delay

• Enable Pins for Main Supplies (EN) and Sensor Supplies (SNSEN)

• Power Sequencing for Advanced Microprocessor Architectures

• SOIC-24WB Package