Monolithic Power Systems Inc. HF500GS-15-P

Overview

HF500GS-15 from Monolithic Power Systems is a fixed-frequency, current-mode flyback regulator IC integrating a 700V/4.5Ω rugged MOSFET, built-in slope compensation, and full protection suite for offline AC/DC power supplies. It delivers up to 15W at 230Vac in open-frame designs, supports frequency foldback (25kHz min), burst mode for <300mW standby, and features timer-based OLP with programmable delay. Used in auxiliary power rails for set-top boxes and home appliances.

For engineers reviewing the HF500GS-15 datasheet, HF500GS-15 pinout, HF500GS-15 application, or HF500GS-15 equivalent, key selection criteria include integrated 700V MOSFET R_DS(on), VCC UVLO hysteresis (4.8V), FB-triggered burst entry (0.7V), OVP latch threshold (27V), and SOIC8-7B thermal resistance (θ_JA = 85°C/W).

Technical Context

The HF500GS-15 implements fixed-frequency current-mode control with internal slope compensation (25mV/μs) to prevent subharmonic oscillation above 50% duty cycle in CCM operation. Its high-voltage start-up current source draws from DRAIN until VCC reaches 12V, then switches to auxiliary winding supply.

Protection logic is tightly coupled: B/O pin enables brown-in/out (0.9V/0.9V thresholds), input OVP (4.5V), and over-power compensation (200mV max offset); TIMER pin integrates soft-start ramp (1V→1.75V), frequency jitter modulation (3.7ms period), and latched OLP timeout (32ms with 47nF capacitor).

Key Specifications

Pinout & Package

HF500GS-15 is housed in a SOIC8-7B package (body size 4.9mm × 6.0mm, 1.27mm pitch), optimized for high-voltage isolation and thermal dissipation in compact offline SMPS designs.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar flyback controller applications.

Compared with MP6004GQ-Z and UCC28740DR, HF500GS-15 provides superior integration for universal-input adapters-combining 700V ruggedness, automatic over-power compensation, and EMI-reducing jitter in one SOIC8-7B package-reducing bill-of-materials count by up to 4 components versus alternatives requiring external slope compensation or OVP circuitry.

Availability

HF500GS-15 is available at Aetrix Electronics and suitable for home appliance auxiliary supplies, set-top box standby rails, and universal-input adapters requiring stable component supply across global manufacturing sites.

Supply support for HF500GS-15 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Monolithic Power Systems (MPS) is a fabless semiconductor company specializing in high-performance analog and mixed-signal ICs for power management, motion control, and automotive applications.

The HF500GS-15 belongs to MPS's HF-series fixed-frequency flyback controllers, designed specifically for cost-sensitive, high-reliability offline AC/DC conversion in consumer and industrial equipment with universal input voltage ranges.

FAQ

What is the maximum continuous output power achievable with HF500GS-15 at 230Vac input?

The HF500GS-15 delivers up to 15W continuous output power in open-frame configurations at 230Vac ±15%, measured at 50°C ambient temperature. This rating assumes proper SOIC8-7B PCB thermal design with 2oz copper and adequate airflow; junction temperature limits output in enclosed adapters to 12W.

How does the over-power compensation function respond to varying input voltages?

Over-power compensation injects a voltage offset (0–247mV) into the current-sense path proportional to the B/O pin voltage, which tracks rectified input voltage. At 265Vac, the full 247mV offset reduces the effective current limit, preventing output power from exceeding 15W; at 85Vac, offset drops to 0mV, allowing full current capability for stable regulation.

Can HF500GS-15 operate without an auxiliary winding for VCC supply?

Yes-the internal high-voltage start-up current source (3.6mA typical at 400V) powers the IC directly from DRAIN until VCC reaches 12V. However, an auxiliary winding is required for sustained operation beyond startup; without it, VCC discharges below UVLO (7V) after initial charge, causing repeated restart cycles.

What protection mechanisms trigger a latched shutdown versus auto-restart behavior?

Only VCC over-voltage (above 27V for 60ms) and TIMER pin forced low (<1.0V for 42μs) cause latched shutdown requiring power-cycle recovery. All other protections-including thermal shutdown (150°C), short-circuit (SCP), and overload (OLP)-feature auto-restart with hysteresis to restore operation once fault conditions clear.

How is frequency jittering implemented and what is its practical EMI benefit?

Frequency jittering modulates the 65kHz oscillator using a triangular TIMER voltage (2.8–3.2V) generated by 10μA charge/discharge currents through the external TIMER capacitor. This spreads spectral energy across ±6.5% bandwidth, reducing peak conducted EMI by 5–8dB in the 150kHz–30MHz range-enabling compliance with CISPR-22 Class B without additional filtering.

What is the minimum recommended TIMER capacitor value for reliable soft-start and OLP timing?

A 47nF capacitor on the TIMER pin is recommended to achieve both 32ms OLP timeout and controlled soft-start duration (~12ms). Values below 33nF risk premature OLP triggering during startup; values above 68nF extend soft-start excessively, risking VCC UVLO dropout under heavy load before regulation establishes.

Does HF500GS-15 support discontinuous conduction mode (DCM) operation?

Yes-the internal slope compensation (25mV/μs) is optimized for CCM but does not prevent DCM operation. At light loads or high transformer turns ratios, the controller naturally transitions to DCM; frequency foldback and burst mode remain fully functional, maintaining efficiency down to no-load conditions.