LF00-based Fixed-Voltage Power Supply
This ECROS Technology power supply kit uses ST Microelectronics LF00-series voltage regulators. These fixed voltage devices have the following features:
- output voltages of 1.25, 1.5, 1.8, 2.5, 2.7, 3.0, 3.3, 3.5, 4.0, 4.5, 4.7, 5.0 5.2, 5.5, 6.0, 8.0, 8.5, 9.0 and 12.0 V
- very low dropout voltage of 0.7V maximum (0.4V typical)
- up to 500mA output current with internal protection against overcurrent
- internal thermal shutdown to protect against overheating
- operating input voltage up to 16V; internal protection up to 30V
- very low quiescent current (typically 0.5 mA for up to 8.0 V output)
- 0.1µF input and 2.2µF (minimum) output bypass capacitors for stability
- excellent regulation down to zero output current
Parts Kit Contents:
† the regulator must be inserted as U2, not U1 |
No Longer Available For PurchaseECROS Technology has closed down and as a result Mini- and Flexi-PSUs are no longer available for purchase. These pages are maintained for the benefit of existing owners. |
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Technical Information
Input Voltage - For the regulator to operate properly, the input voltage to the PSU must always be the output voltage plus the regulator dropout voltage plus the voltage drop across D1, if used. For example, with a 5V regulator and D1 installed as shown, the input voltage must be at least 6.5V (5 + 0.7 + 0.8). This includes supply ripple. Continuing the example, if, at full load, ripple causes the input voltage to drop 0.5V below its average value during each half-cycle, then the average input voltage should be 7V.
Power Dissipation - Heat dissipated in the regulator, in watts, will be the product of the load current in amps and the voltage dropped across the regulator. Again, using the above example, suppose you apply an input voltage of 9V. The regulator will drop 3.2V (9 - 5 - 0.8). At 0.5 amps, the heat dissipated will be 1.6W (3.2 x 0.5). ECROS Technology recommends that you limit power dissipation in the regulator to 3W with the compact heatsink supplied in the kit. This is based on personal safety concerns. At higher power, the circuit will continue to function but the heatsink will become very hot. If you touch it, you may not pull away fast enough to avoid some lasting discomfort.
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