SR087SG-G - Off-Line Inductorless Switching Regulator | Microchip
MPN: SR087SG-G β Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $1.86 | $1.86 |
| 10 | $1.67 | $16.70 |
| 100 | $1.45 | $145.00 |
| 500 | $1.28 | $640.00 |
| 1,000 | $1.12 | $1,120.00 |
SR087SG-G Overview
An off-line inductorless switching regulator is a type of AC/DC converter, part of the broader power management IC (PMIC) hierarchy, that produces a regulated low-voltage DC rail directly from the rectified AC mains without using magnetic components such as transformers or inductors. This topology sits between conventional linear regulators and flyback converters: it achieves galvanic-unisolated, magnet-free regulation, dramatically simplifying the bill of materials for low-power mains-powered products.
Key features of the SR087SG-G include efficient operation without magnetics, elimination of high-voltage capacitors from the power path, an adjustable main output voltage, a 5.0V internal regulator supporting up to 100 mA combined output current, and a single bill of materials that covers both 120VAC and 230VAC line inputs. Built-in soft start limits inrush current at power-up, and standby consumption is less than 200 mW, helping designs meet low no-load power requirements.
Architecturally, the SR087 (originally a Supertex part, now under Microchip Technology) regulates by controlling charge transferred to an external capacitor, switching only when the storage capacitor requires replenishment. This charge-transfer control keeps switching losses low and allows the external components to remain small, low-voltage parts rather than bulky magnetics or 400V film capacitors.
Typical applications include home appliances with low-power standby supplies, white goods control panels, smart meters and energy monitoring nodes, LED lighting control interfaces, and industrial auxiliary power for microcontrollers such as PIC MCUs that need a clean 5V rail from the AC line.
A key design consideration is thermal and energy-budget sizing: because the topology is inductorless and unisolated, the entire circuit floats at mains potential, and the 100 mA combined output budget must account for both the 5V rail and the adjustable output. Never probe or connect user-accessible circuitry without isolation.
This page synthesizes distributor pricing, family drop-in alternatives, and practical design notes not found in the manufacturer datasheet.
Drop-in alternatives for SR087SG-G β same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
SR036SG-G
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
SR037SG-G
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
SR087SG-G Maximum Ratings & Electrical Characteristics
| Topology | Inductorless off-line switching regulator |
| Input Type | Rectified AC line (120VAC/230VAC single BOM) |
| Main Output Voltage | 5.0 V |
| Auxiliary Output Voltage | Adjustable (up to 50 V) |
| Combined Output Current | Up to 100 mA |
| Standby Power Consumption | Less than 200 mW |
| Soft Start | Built-in |
| Magnetics Requirement | None (inductorless, transformerless) |
| High Voltage Capacitors Required | No |
| Package | 8-SOIC with exposed pad (SOIC-8-EP) |
| Mounting Type | Surface Mount |
| Category | PMIC - AC/DC Converters, Offline Switchers |
| Isolation | Non-isolated (line-referenced) |
SR087SG-G 8-soic with exposed pad (soic-8-ep) Pin Configuration Guide
Pin configuration for SR087SG-G (8-soic with exposed pad (soic-8-ep) package). This power device features gate, drain, and source terminals. For non-polarized packages, refer to the manufacturer datasheet for exact pin 1 orientation and footprint details. Common applications include power supply design, motor driving, and load switching.
No detailed pinout data available for SR087SG-G.
Refer to the datasheet for full pin configuration.
Typical Applications
SR087SG-G is suitable for 6 applications: Appliance Standby Power Supply, Smart Meters and Energy Monitoring, LED Lighting Control Interfaces, Industrial Auxiliary and Panel Power, White Goods Control Boards, HVAC and Thermostat Electronics.
Appliance Standby Power Supply
Home appliances such as washing machines, microwave ovens, and air conditioners require a small always-on supply for microcontrollers, touch panels, and relay drivers while the main power stage is off. The SR087SG-G fits this role because it rectifies the AC line directly and delivers a regulated 5.0V rail with less than 200 mW standby consumption, helping products meet stringent no-load power limits. Since it needs no transformer and no high-voltage capacitors, the standby supply occupies minimal PCB area inside the appliance control board. The single bill of materials covering 120VAC and 230VAC lets one control-board design serve global markets. The 100 mA combined output budget comfortably powers an MCU, indicator LEDs, and a relay coil in standby.
Recommended
Smart Meters and Energy Monitoring
Smart electricity meters and sub-metering nodes must harvest their operating power from the measured AC line while keeping no-load losses negligible, because standby loss is metered and regulated in many jurisdictions. The SR087SG-G addresses this directly: it draws charge from the rectified line only as needed, achieving under 200 mW consumption, and provides a clean 5.0V rail for the metering MCU, RTC, and communication radio within the 100 mA combined budget. The magnetics-free topology reduces height and cost in sealed meter enclosures, and the universal 120VAC/230VAC single BOM simplifies certification for regional meter variants. Because the output is line-referenced and non-isolated, metering circuitry must remain fully enclosed per safety standards.
Recommended
LED Lighting Control Interfaces
LED luminaires and lighting controllers need a small auxiliary supply for occupancy sensors, wireless modules, and dimming interfaces, separate from the high-current LED driver stage. The SR087SG-G supplies this auxiliary rail directly from the rectified AC line without adding magnetics, keeping the luminaire driver PCB compact and low-cost. Its adjustable output up to 50V can bias sensor or gate-drive circuitry, while the 5.0V internal regulator powers a microcontroller and radio within the 100 mA combined limit. Standby draw below 200 mW supports ENERGY STAR-style low standby requirements for connected lighting. The line-referenced, non-isolated nature means the auxiliary circuit must be housed within the luminaire's insulated enclosure and remain user-inaccessible during operation and service.
Recommended
Industrial Auxiliary and Panel Power
Industrial control panels, contactor modules, and sensor interfaces frequently need a low-power logic supply derived from the AC line without the cost and space of a control transformer. The SR087SG-G provides a regulated 5.0V rail for panel microcontrollers, indicators, and communication transceivers with a single bill of materials valid from 120VAC to 230VAC, eliminating regional component variants in exported equipment. Its built-in soft start limits inrush when panels are energized, protecting upstream breakers, and the inductorless topology survives vibration environments where transformer terminations can fatigue. With a 100 mA combined output budget, designers should budget the rail across all panel loads and add post-regulation, such as an LDO, for sensitive analog front ends on the same board.
Recommended
White Goods Control Boards
White goods such as refrigerators, dishwashers, and dryers use sealed control boards that run continuously and therefore demand an efficient, low-heat, low-cost mains-derived logic supply. The SR087SG-G converts the rectified AC line to a regulated 5.0V output with no magnetics and no high-voltage capacitors, reducing component count on high-volume boards and eliminating transformer height constraints in slim control enclosures. Soft start prevents nuisance tripping when the appliance cycles power, and sub-200 mW standby consumption contributes to appliance energy-label compliance. The 100 mA combined output covers the user-interface MCU, touch sensing, buzzer, and triac gate drive; heavier loads such as motor drives remain on separate switching stages. The line-referenced design requires full user isolation per appliance safety standards.
Recommended
HVAC and Thermostat Electronics
Line-powered thermostats, HVAC controllers, and boiler interface boards need a compact always-on supply for the thermostat MCU, display, and relay or triac drivers. The SR087SG-G derives its 5.0V rail directly from the rectified 120VAC or 230VAC line without a transformer, fitting the tight space behind wall-mounted thermostat housings, and its sub-200 mW standby draw keeps continuous power losses minimal over year-round operation. The adjustable output up to 50V can supply higher-voltage sensing or gate-drive bias, while the internal 5V regulator feeds the control electronics within the 100 mA combined budget. Because the circuit is line-referenced and non-isolated, the entire thermostat electronics assembly must be double-insulated and inaccessible to the user, in line with HVAC control safety practice.
Recommended
Recommended Products Summary
Engineering reference data for SR087SG-G β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | SR036SG-G | SR037SG-G |
|---|---|---|---|
| Package | 8-SOIC-EP | 8-SOIC-EP - same | 8-SOIC-EP - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology |
| Topology | Inductorless off-line switching regulator | Inductorless off-line switching regulator | Inductorless off-line switching regulator |
| Input | Rectified 120VAC/230VAC line, single BOM | Rectified AC line, single BOM | Rectified AC line, single BOM |
| Standby Power | Less than 200 mW | Low standby (family specification) | Low standby (family specification) |
| Soft Start | Built-in | Built-in | Built-in |
| Magnetics Required | None | None | None |
Key Differentiators
- Truly inductorless off-line regulation (vs Conventional flyback controller ICs)
- Single BOM for 120VAC and 230VAC (vs SR036SG-G / SR037SG-G family variants)
- Adjustable output up to 50V plus 5V rail (vs Capacitive-dropper supplies)
Design Notes
The SR087SG-G is a non-isolated, line-referenced regulator: the entire application circuit floats at mains potential when powered from the rectified AC line. Never connect measurement instruments, programming tools, or user-accessible connectors to the circuit without an isolation transformer. All creepage and clearance distances on the PCB must respect the highest line voltage (230VAC designs), and the exposed pad soldered area must not be touched during operation.
The 100 mA combined output current is shared between the 5.0V regulator and the adjustable output, so budget both rails before finalizing the load list. Estimated: if the adjustable output supplies 20 mA, only 80 mA remains for the 5V rail and its loads. The sub-200 mW standby specification applies to the no-load condition; verify standby power with your complete circuit connected, since external resistor dividers on the adjustable output contribute standing current.
Keep the charge-storage capacitor and rectifier network close to the SR087SG-G pins to minimize high-frequency loop area, and solder the exposed pad to an adequate copper area for heat spreading and low-impedance return. Because no magnetics are used, radiated emissions are typically manageable, but switching bursts still require a compact input loop and a properly rated rectifier. Follow the datasheet typical application circuit values exactly - the single-BOM claim for 120VAC/230VAC depends on those specific component ratings.
Built-in soft start limits inrush at power-up, but downstream bulk capacitance beyond the datasheet recommended value can extend startup beyond the soft-start window and cause hiccup or failure to start. If your load requires larger reservoir capacitance, verify startup across both 120VAC and 230VAC, at minimum and maximum load, and across the temperature range, before releasing the design to production.
Compliance Information
Compliance status not stated in the provided web data; verify RoHS/REACH status on the official Microchip product page or distributor compliance documentation before design-in.
