ZHCSL44A April 2020 – September 2020 LM25183
PRODUCTION DATA
| PIN | I/O(1) | DESCRIPTION | |
|---|---|---|---|
| NO. | NAME | ||
| 1 | SW | P | Switch node that is internally connected to the drain of the N-channel power MOSFET. Connect to the primary-side switching terminal of the flyback transformer. |
| 2 | FB | I | Primary-side feedback pin. Connect a resistor from FB to SW. The ratio of the FB resistor to the resistor at the RSET pin sets the output voltage. |
| 3 | VIN | P/I | Input supply connection. Source for internal bias regulators and input voltage sensing pin. Connect directly to the input supply of the converter with short, low impedance paths. |
| 4 | EN/UVLO | I | Enable input and undervoltage lockout (UVLO) programming pin. If the EN/UVLO voltage is below 1 V, the converter is in shutdown mode with all functions disabled. If the EN/UVLO voltage is greater than 1 V and below 1.5 V, the converter is in standby mode with the internal regulator operational and no switching. If the EN/UVLO voltage is above 1.5 V, the start-up sequence begins. |
| 5 | SS/BIAS | I | Soft start or bias input. Connect a capacitor from SS/BIAS to GND to adjust the output start-up time and input inrush current. If SS/BIAS is left open, the internal 6-ms soft-start timer is activated. Connect an external supply to SS/BIAS to supply bias to the internal voltage regulator and enable internal soft start. |
| 6 | TC | I | Temperature compensation pin. Tie a resistor from TC to RSET to compensate for the temperature coefficient of the forward voltage drop of the secondary diode, thus improving regulation at the secondary-side output. |
| 7 | RSET | I | Reference resistor tied to GND to set the reference current for FB. Connect a 12.1-k? resistor from RSET to GND. |
| 8 | GND | G | Analog and power ground. Ground connection of internal control circuits and power MOSFET. |