Small Split Rail Isolated + - 5V Power Supply Generator
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- Small Split Rail Isolated + - 5V Power Supply Generator User Guide
(PDF 1251 KB)
27 Jan 2012
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.
|Input Range||Output 1||Output 2|
|Max 29V|| 250 mA
|| 250 mA
The performance of the reference design is as follows:
- Very Low Noise, <20 mV P-P
- Fully Isolated Outputs, > 500V
- Small Size
- Wide Input Range 10V - 29V
- Double sided PCB
- 600 KHz Operation