Monolithic Power Systems Inc. HF500GP-40

Overview

HF500GP-40 from Monolithic Power Systems is a fixed-frequency, current-mode flyback regulator IC integrating a 700V/1Ω MOSFET and full protection suite for offline AC/DC power supplies. It delivers up to 45W in open-frame designs (230VAC ±15%), operates at 65kHz nominal switching frequency with ±6.5% jitter, reduces frequency to 25kHz under light load, and enters burst mode below 0.7V FB for <300mW standby power - used in compact auxiliary and adapter power supplies.

For engineers reviewing the HF500GP-40 datasheet, HF500GP-40 pinout, HF500GP-40 application, or HF500GP-40 equivalent, key selection considerations include integrated high-voltage MOSFET rating, over-power line compensation behavior, multi-mode efficiency control (fixed-frequency/jitter/foldback/burst), thermal shutdown hysteresis (25°C), and PDIP8-7B package compatibility with through-hole board assembly.

Technical Context

The HF500GP-40 implements current-mode control with built-in slope compensation (18–31 mV/μs) to prevent subharmonic oscillation at >50% duty cycle in CCM. Its oscillator uses a TIMER pin-controlled triangular waveform (2.8–3.2V) to generate frequency jittering (±4.5–±8%) and enable programmable soft-start via external capacitor timing.

Protection logic is distributed across dedicated pins: B/O senses input brown-in/out (0.9V/0.9V thresholds), OVP (4.5V), and over-power compensation; TIMER integrates latch-off (0.7–1.5V threshold), OLP timing (32ms delay), and external OTP/OVP interface; SOURCE monitors primary current for VILIM (1.0V), VSCP (1.5V), and leading-edge blanking (250/300ns).

Key Specifications

Pinout & Package

HF500GP-40 is housed in a PDIP8-7B package - an 8-pin plastic dual-inline package with 7 functional leads (pin 3 omitted) and internal drain-to-package thermal connection. The package supports manual soldering (260°C lead temp) and meets RoHS/lead-free/halogen-free requirements.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MP6004GJ-Z and UCC28740DR, HF500GP-40 uniquely combines 700V integration, over-power line compensation, multi-mode efficiency control (jitter/foldback/burst), and PDIP8-7B thermal robustness - making it optimal for universal-input, safety-critical, and EMI-constrained adapter designs.

Availability

HF500GP-40 is available at Aetrix Electronics and suitable for home appliance power supplies, set-top box auxiliary rails, and adapter power supplies requiring stable component supply, long-term lifecycle support, and RoHS-compliant manufacturing.

Supply support for HF500GP-40 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 power management ICs, with over two decades of expertise in integrated DC/DC and AC/DC solutions.

The HF500GP-40 belongs to MPS's HF-series of fully integrated offline flyback controllers - designed specifically for compact, high-reliability, universal-input AC/DC power supplies targeting consumer, industrial, and networking applications.

FAQ

What is the purpose of the B/O pin on HF500GP-40?

The B/O pin serves three functions: brown-in/out detection (0.9V thresholds), input over-voltage protection (4.5V trigger), and over-power line compensation. It senses input voltage via an external resistor divider; when pulled above 6V, all B/O-related functions are disabled. This pin enables single-point monitoring of AC line health and dynamic adjustment of current-limit thresholds.

How does frequency jittering reduce EMI in HF500GP-40?

Frequency jittering modulates the 65kHz switching frequency by ±6.5% using a TIMER pin-controlled triangular waveform. This spreads electromagnetic energy across a ~8.5kHz bandwidth instead of concentrating it at discrete harmonics, lowering peak conducted EMI by up to 10dB and easing compliance with CISPR 22/32 Class B limits without additional filtering.

Can HF500GP-40 operate without an auxiliary winding?

No - the HF500GP-40 relies on the auxiliary winding to power VCC after startup. During initial power-up, it draws start-up current from DRAIN (3.6mA at 400V), but once VCC reaches 12V, the internal HV current source disables. Without auxiliary supply, VCC drops below 7V UVLO threshold and cycling occurs, preventing stable regulation.

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

The minimum recommended TIMER capacitor is 47nF, which yields ~1.4ms soft-start duration (T_SS = 0.3 × C_TIMER). Smaller values risk excessive inrush current and transformer saturation; larger values extend startup time unnecessarily. A 47nF X7R ceramic capacitor is standard for balanced stress reduction and response time.

How does over-power line compensation affect overload protection?

Over-power compensation adds a voltage offset (up to 247mV) to the current-sense threshold based on B/O voltage, reducing the effective VILIM (1.0V) proportionally at high input voltages. This ensures the OLP trip point remains constant across 85–265VAC - eliminating need for input-voltage-dependent OLP resistor networks.

Is HF500GP-40 compatible with discontinuous conduction mode (DCM) designs?

Yes - the HF500GP-40 supports both DCM and CCM operation. Its internal slope compensation (18–31 mV/μs) stabilizes current-mode control even at >50% duty cycles, but DCM operation is naturally achieved by selecting appropriate primary inductance (KP ≈ 1). Designers may optimize KP between 0.6–0.8 for universal input or use higher KP for 230VAC-only designs.

What thermal derating applies to HF500GP-40 in PDIP8-7B package?

In PDIP8-7B, HF500GP-40 has θ_JA = 105°C/W. At 50°C ambient, max continuous power is limited to (150°C − 50°C)/105°C/W = 0.95W - but actual output power (up to 45W) is enabled by efficient heat transfer from the internal drain pad to PCB copper. Derating begins above 50°C ambient unless additional copper area or airflow is provided.