SNVS123D April 1998 – May 2016 LM2599
PRODUCTION DATA.
PIN | I/O | DESCRIPTION | |
---|---|---|---|
NO. | NAME | ||
1 | +VIN | I | This is the positive input supply for the IC switching regulator. A suitable input bypass capacitor must be present at this pin to minimize voltage transients and to supply the switching currents needed by the regulator. |
2 | Output | O | Internal switch. The voltage at this pin switches between approximately (+VIN − VSAT) and approximately −0.5 V, with a duty cycle of VOUT/VIN. To minimize coupling to sensitive circuitry, the PCB copper area connected to this pin must be kept to a minimum. |
3 | Error Flag | O | Open-collector output that provides a low signal (flag transistor ON) when the regulated output voltage drops more than 5% from the nominal output voltage. On start up, Error Flag is low until VOUT reaches 95% of the nominal output voltage and a delay time determined by the Delay pin capacitor. This signal can be used as a reset to a microprocessor on power-up. |
4 | Ground | — | Circuit ground. |
5 | Delay | O | At power-up, this pin can be used to provide a time delay between the time the regulated output voltage reaches 95% of the nominal output voltage, and the time the error flag output goes high. |
6 | Feedback | I | Senses the regulated output voltage to complete the feedback loop. |
7 | Shutdown/Soft-start | I | This dual function pin provides the following features: (a) Allows the switching regulator circuit to be shut down using logic level signals thus dropping the total input supply current to approximately 80 μA. (b) Adding a capacitor to this pin provides a soft-start feature which minimizes start-up current and provides a controlled ramp up of the output voltage. |