SRK1000ATR

Power Supply Controllers, Monitors Overview

The SRK1000ATR is an adaptive synchronous rectification controller designed for secondary-side rectification in flyback converters. It supports quasi-resonant (QR) and mixed CCM/DCM fixed-frequency operation modes. The device features a wide Vcc operating voltage range of 3.75V to 32V and supports CC regulation down to 2V output. Key electrical parameters include a maximum operating frequency of 300 kHz, a high-voltage sensing input rated for 100V AMR, and a supply current of 17 mA. It operates within a temperature range of -40°C to +150°C TJ and is housed in a SOT-23-6 package.

Power Supply Controllers, Monitors Feature Summary

• Implements adaptive turn-off logic to maximize conduction time and eliminate parasitic inductance effects.
• Features fast turn-on with minimum delay for efficient N-channel MOSFET driving.
• Includes low consumption mode entry via primary side burst-mode detection or minimum TON monitoring.
• Provides programmable minimum on-time and fixed minimum off-time options.

Power Supply Controllers, Monitors Applications

• Adapters
• Battery chargers
• USB power supplies

Power Supply Controllers, Monitors Procurement Notes

Verify the specific suffix 'A' against the datasheet to confirm the fixed minimum off-time configuration, as this variant differs from SRK1000 and SRK1000B. Ensure the ordering code matches the required tape and reel packaging format. Confirm RoHS compliance status through official documentation before finalizing procurement specifications.

Power Supply Controllers, Monitors Selection Notes

Select this component for flyback converters requiring optimized secondary-side synchronous rectification. It is suitable for both QR and fixed-frequency mixed DCM/CCM applications. Consider the SOT-23-6 package constraints and the requirement for N-channel MOSFETs compatible with the provided gate-drive output capabilities.

Power Supply Controllers, Monitors Part Context

The SRK1000 series includes variants SRK1000, SRK1000A, and SRK1000B, distinguished by their programmable timing settings. The SRK1000ATR specifically denotes the A-variant in tape-and-reel packaging. This family is engineered to improve converter efficiency at light loads by entering low-power modes when synchronous rectification is no longer beneficial.

Power Supply Controllers, Monitors Replacement Considerations

Public confirmed substitute part numbers are not available in the provided documentation. Designers should consult STMicroelectronics for direct replacements or verify compatibility with alternative synchronous rectification controllers if the SRK1000ATR is discontinued.

Power Supply Controllers, Monitors FAQ

How does the SRK1000ATR enter low consumption mode?

It enters low consumption mode when it detects primary controller burst-mode operation or when the SR MOSFET conduction becomes lower than the programmed minimum TON.

What control scheme does the SRK1000ATR use?

The SR MOSFET is switched on as soon as current starts flowing through its body diode and is switched off as current approaches zero, utilizing adaptive turn-off logic.