Monolithic Power Systems Inc. HF500GS-15

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. It delivers up to 15W at 230Vac±15% in open-frame designs and supports frequency jittering (±6.5%), burst mode, and frequency foldback down to 25kHz for high light-load efficiency in offline AC/DC adapters.

For engineers reviewing the HF500GS-15 datasheet, HF500GS-15 pinout, HF500GS-15 application, or HF500GS-15 equivalent, key selection considerations include its integrated 700V MOSFET ruggedness, timer-based OLP with programmable delay, over-power compensation independent of input voltage, and SOIC8-7B package compatibility with universal-input flyback topologies.

Technical Context

The HF500GS-15 implements fixed-frequency current-mode control with internal slope compensation (18–31 mV/μs) to prevent subharmonic oscillation above 50% duty cycle in CCM operation. Its oscillator operates at 65kHz nominal with ±6.5% jitter amplitude modulated by a TIMER pin-controlled triangular waveform (2.8–3.2V), reducing conducted EMI without external components.

Protection architecture centers on multi-threshold, timer-integrated functions: B/O pin enables brown-in/out (0.9V/0.9V thresholds), input OVP (4.5V), and over-power compensation (0–270mV offset); TIMER pin provides latch-off capability (1V threshold, 42μs blanking) for external OTP/OVP, while SOURCE pin senses primary current with dual LEB (270ns/350ns) for SCP and foldback stability.

Key Specifications

Pinout & Package

HF500GS-15 is housed in a SOIC8-7B package - an industry-standard 8-pin surface-mount outline with exposed pad thermal enhancement and 7 functional pins (Pin 3 omitted per MPS specification).

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 delivers superior light-load efficiency via burst mode and frequency foldback, tighter universal-input regulation via B/O-based over-power compensation, and lower EMI through integrated jitter-without requiring external slope compensation or input OVP components.

Availability

HF500GS-15 is available at Aetrix Electronics and suitable for home appliance power supplies, set-top box adapters, industrial auxiliary power, and universal-input AC/DC adapters requiring stable component supply, long-lifecycle support, and RoHS-compliant manufacturing.

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 power ICs, with design centers in the US, China, and Taiwan, and global distribution through authorized partners.

The HF500GS-15 belongs to MPS's HF500 series of highly integrated flyback controllers, engineered specifically for cost-sensitive, universal-input offline power supplies demanding high ruggedness, low standby power, and simplified EMI compliance.

FAQ

What is the maximum continuous output power of HF500GS-15 at 230Vac?

At 230Vac±15% in an open-frame design at 50°C ambient, HF500GS-15 delivers up to 15W continuous output power. In non-ventilated enclosed adapters, the limit is 12W due to thermal derating. Junction temperature remains the ultimate constraint-exceeding 125°C reduces allowable power per θJA = 85°C/W.

How does the over-power compensation function maintain constant output power?

Over-power compensation adds a voltage offset (0–270mV) to the FB node proportional to the B/O pin voltage, which tracks input voltage. This dynamically adjusts the current-limit threshold to counteract input-voltage-induced power variation, ensuring ±3% output power regulation across 85–265Vac without secondary-side sensing.

Can HF500GS-15 operate without an auxiliary winding?

Yes-HF500GS-15 starts up using its internal high-voltage current source drawn from the DRAIN pin, eliminating need for auxiliary winding during initial startup. Once VCC reaches 12V, the IC switches to auxiliary supply; if auxiliary fails, it reverts to DRAIN sourcing, enabling single-winding designs with robust fault tolerance.

What protection features are latched versus auto-restarting?

VCC OVP (at 27V) and TIMER latch-off (below 1V for 42μs) cause permanent shutdown until power cycle. All other protections-including thermal shutdown (150°C), SCP, OLP, and brownout-feature auto-restart with hysteresis to restore operation after fault removal and cooldown.

Is the SOIC8-7B package thermally enhanced?

Yes-the SOIC8-7B package used for HF500GS-15 includes an exposed thermal pad (Pin 3 omitted) that must be soldered to a copper pour for optimal heat dissipation. With θJC = 40°C/W, this pad reduces junction-to-case thermal resistance by ~35% compared to standard SOIC8, critical for sustaining 15W output in compact layouts.

How is frequency jitter implemented without external components?

Frequency jitter is generated internally by comparing a TIMER pin triangular waveform (2.8–3.2V, 3.7ms period with 47nF) against a controlled current source. The oscillator frequency varies ±6.5% around 65kHz, spreading spectral energy without requiring external clock modulation circuitry or additional passives.

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

A 47nF capacitor on the TIMER pin provides a 1.4ms soft-start duration (per Tsoft = 0.3 × CTIMER × 10⁻³), sufficient for most 12V/1A adapters. Values below 22nF risk incomplete soft-start at full load; values above 100nF may extend startup beyond 3ms, increasing stress on primary-side components during initial surge.