Document Number: MC33998
Rev. 2.0, 8/2006
Switching Power Supply with
The 33998 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 2.6 V linear
regulator uses an external pass transistor to reduce the 33998 power
dissipation. The 33998 also provides a 2.6 V linear standby regulator
and two 5.0 V sensor supply outputs protected by internal low-
resistance LDMOS transistors.
There are two separate enable pins for the main and sensor supply
www.DataSheeto4uUtp.cuotms and standard supervisory functions such as resets with
power-up reset delay.
The 33998 provides proper power supply sequencing for
advanced microprocessor architectures such as the MPC5xx and
683xx microprocessor families.
EG SUFFIX (PB-FREE)
• 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 = 2.6 V @
-40°C to 125°C
• Low-Power Standby Linear Regulator VKAM = 2.6 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
• Pb-Free Packaging Designated by Suffix Code EG
5.0 V VREF1
5.0 V VREF2
Figure 1. 33998 Simplified Application Diagram
Freescale Semiconductor, Inc. reserves the right to change the detail specifications, as
may be required, to permit improvements in the design of its products.
© Freescale Semiconductor, Inc., 2007. All rights reserved.