1 Features
1• Internal Series-Pass and Step-Up Switching
Regulator
• Output Adjustable From 2.9 V to 30 V
• 1-V to 10-V Input for Switching Regulator
• 4.5-V to 32-V Input for Series Regulator
• Externally Controlled Switching Current
• No External Rectifier Required

2 Applications
• Voltage Boosting
• Dual-Supply Voltage Reglation AC•
Battery Back-Ups
• Microprocessor Memory Power

3 Description
The TL499A device is an integrated circuit designed
to provide a wide range of adjustable regulated
supply voltages. The regulated output voltage can be
varied from 2.9 V to 30 V by adjusting two external
resistors. When the TL499A is ac-coupled to line
power through a step-down transformer, it operates
as a series DC voltage regulator to maintain the regulated output voltage. With the addition of a
battery from 1.1 V to 10 V, an inductor, a filter
capacitor, and two resistors, the TL499A operates as
a step-up switching regulator during an AC-line
failure. The adjustable regulated output voltage makes the TL499A useful for a wide range of
applications. Providing backup power during an AC•
line failure makes the TL499A extremely useful in
microprocessor memory applications. The TL499AC
is characterized for operation from –20°C to +85°C.