SR087SG-G Microchip

SR086/SR087 Adjustable Offline Inductorless Switching Regulators Features General Description Efficient Operation without Magnetics The SR086/SR087 are inductorless switching regulators designed to operate directly from a rectified No High-voltage Capacitors AC line. The operating principle is to turn on a pass Adjustable Main Output Voltage (9V to 50V) transistor when the rectified AC is below the output Additional Internal Linear Regulator: voltage and to turn it off when the output voltage - 3.3V for SR086 reaches a specific level. The ICs feature an adjustable - 5V for SR087 main output voltage of 9V to 50V and an additional fixed output of 3.3V for SR086 and 5V for SR087. Up to 100 mA Combined Output Current Efficiencies of around 55% may be realized for loads Single BOM for 120 VAC/230 VAC up to 1W in 120 VAC applications and about 50% Built-in Soft Start efficiencies for loads up to 800 mW in 230 VAC Less than 200 mW Standby Power applications. A logic-level enable input allows the SR086/SR087 to Applications be disableduseful when they are employed as keep-alive power supplies. White Goods Household Appliances Lighting Controls Circuit Breakers Keep-alive Supplies Package Type 8-lead SOIC (with Heat Slug) (Top view) GATE VIN 1 8 2 7 VGD EN 3 6 VOUT GND VFB VREG 4 5 Heat Slug Backside on the SOIC package is at ground potential and may be connected to ground or left unconnected. See Table 2-1 for pin information. WARNING Galvanic isolation is not provided. Dangerous voltages are present when connected to the AC line. It is the responsibility of the designer using the SR086/SR087 to ensure that adequate security measures are in place to protect the end user from electrical shock. The circuits shown in this data sheet are not guaranteed to meet surge and conducted EMI requirements. The effectiveness of these circuits may vary with a particular application. The designer must conduct tests to ascertain compliance with applicable standards and regulations. 2017 Microchip Technology Inc. DS20005544A-page 1SR086/SR087 Functional Block Diagrams 1.25A 1.0kV 90 to 9.0 - 50VDC 1.0A STGD5NB120SZ 270VAC 275V 50/60Hz 50A R C R PD GD C C GD OUT1 OUT 390k 100nF 1.0F 470F 1.1M VIN GATE VGD VOUT 13V V - 1 R OUT Q R = R FB(HI) FB(LO) S 1.25V Upper circuitry Level powered by V - V GD OUT Translator Lower circuitry powered by V - GND OUT FB EN 1.25V VREG REG 3.3V R FB(LO) SR086 C 12.4k REG 100nF GND 1.25A 1.0kV 90 to 1.0A 9.0 - 50VDC STGD5NB120SZ 270VAC 275V 50/60Hz 50A R PD C R C 1 C GD GD OUT OUT 390k 100nF 1.0F 470F 1.1M VIN GATE VGD VOUT 13V V - 1 OUT R R = R Q FB(HI) FB(LO) S 1.25V Upper circuitry Level powered by V - V GD OUT Translator Lower circuitry powered by V - GND OUT FB EN 1.25V VREG REG 5.0V R FB(LO) SR087 C 12.4k REG 100nF GND DS20005544A-page 2 2017 Microchip Technology Inc.