SMSPLITRAILISO-REF Reference Design

Texas Instruments

Small Split Rail Isolated + - 5V Power Supply Generator

Description

A very low noise differential power supply for split rail systems requiring +5V and -5V (higher or lower voltage is possible). This design is fully isolated and capable of floating to over 500V differential from Vin to Vout (higher is possible). The LM5001 IC is a fully integrated flyback regulator which performs all of the current mode control for tight regulation and transient response. This design is a smaller version of RD-171. Design uses smaller components on only one side of a double sided FR4 PCB.This design provides low noise bias rails for ground referenced analog circuitry (under 2 mV p-p ripple noise up to 1 GHz). The design utilizes a very small size PCB footprint. This approach is ideal for many applications including low noise cable drivers: medical electronics: high fidelity low power audio: and other sensitive circuitry that can benefit from very low noise split rail biasing. Input to output isolation is employed for those applications where the input and output voltages might be at different potentials or when the input voltage travels across cabling which might pickup noise. The floating outputs avoid unwanted ground currents and the potential for additional noise pickup. For those that do not require isolation they can remove the feedback isolation section of the design and use a simple resistor divider for setting the feedback voltage.

Features
  •  Input RangeOutput 1Output 2  LM5001   Min 10V    5V    -5V    Max 29V    250 mA    250 mA  The performance of the reference design is as follows:Very Low Noise: Fully Isolated Outputs: > 500VSmall SizeWide Input Range 10V - 29VDouble sided PCB600 KHz Operation 
Applications
Product Categories
  • Power management

Parts

Part Number Name Companion Part
LM5001 LM5001 Buy Datasheet
LM5002 LM5002 Buy Datasheet