Monolithic Power Systems Inc. HFC0310GS-Z

Overview

HFC0310GS-Z from Monolithic Power Systems is a programmable fixed-frequency flyback controller in SOIC8 package, implementing peak current-mode control with burst-mode operation for <12 μA start-up current, 11–20 V operating VCC range, and up to 600 kHz switching frequency set via external FSET capacitor - used in AC/DC adapters delivering multi-output 12V/0.8A + dual 8V rails.

For engineers reviewing the HFC0310GS-Z datasheet, HFC0310GS-Z pinout, HFC0310GS-Z application, or HFC0310GS-Z equivalent, key selection criteria include its active-burst mode standby power reduction, VCC UVLO hysteresis (VCCL = 8.5 V, VCCH = 13.2 V), FB-based OLP delay (82 ms at 100 kHz), and PRO-pin configurable external protection with 0.2 V hysteresis.

Technical Context

The HFC0310GS-Z employs peak-current-mode PWM control with internal slope compensation (27–57 mV/μs at 100 kHz) and dual leading-edge blanking (tLEB1 = 180–400 ns, tLEB2 = 150–370 ns) to ensure stable regulation under transient load steps and prevent false triggering from switching noise. Its feedback loop uses FB pin voltage division (IDIV = 3.5×) to set current-sense threshold, enabling precise output voltage regulation across line and load variations.

Burst-mode operation is triggered by FB voltage falling below VBURL = 0.50 V and exits when rising above VBURH = 0.73 V, enabling sub-100 mW no-load power consumption. Protection logic integrates time-based over-load detection (8192-cycle delay), short-circuit shutdown at VSCP = 1.72 V on CS pin, and thermal shutdown at 150 °C with 40 °C recovery hysteresis.

Key Specifications

Pinout & Package

Available in SOIC8 package (JEDEC MS-012 AA, 3.9 mm × 4.9 mm × 1.75 mm), with exposed pad not electrically connected. Thermal resistance θJA = 96 °C/W on 4-layer PCB.

Key Features

Applications

Equivalent & Alternatives

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

Compared with UCC28740DR and ICE2QS03G, the HFC0310GS-Z delivers superior light-load efficiency via active burst mode with defined entry/exit thresholds, full programmability of switching frequency, and a dedicated PRO pin for coordinated system-level protection - making it optimal for regulated multi-output adapters and industrial power supplies demanding low standby power and robust fault handling.

Availability

HFC0310GS-Z is available at Aetrix Electronics and suitable for AC/DC adapters, smart meter power supplies, and industrial IoT edge node PSUs requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for HFC0310GS-Z 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 manufacturing partnerships.

The HFC0310 belongs to MPS's AC/DC flyback controller product line, engineered specifically for high-efficiency, low-standby-power offline SMPS in consumer, industrial, and metering applications - emphasizing integration, protection robustness, and EMI performance.

FAQ

What is the minimum FSET capacitor value needed to achieve 600 kHz operation?

The HFC0310GS-Z achieves 600 kHz with a 120 pF capacitor on FSET, based on its internal 50 μA current source and 0.87 V max FSET voltage. Lower capacitance increases frequency but reduces noise-shaping margin; values below 100 pF risk instability due to parasitic sensitivity and reduced blanking margin.

How does the PRO pin interact with other protection features like OVP or OTP?

The PRO pin operates independently of internal protections: it forces immediate shutdown when pulled above 3.3 V, overriding normal operation regardless of VCC OVP or thermal status. Recovery occurs only after PRO falls below 3.1 V and VCC re-enters UVLO hysteresis window - enabling priority-based fault escalation in system-level safety architectures.

Can the HFC0310GS-Z drive a 1 Ω gate resistor directly without external buffering?

Yes - its Drv pin delivers 25 Ω source and 13 Ω sink impedance, capable of driving a 1 Ω gate resistor with <10 ns rise/fall times for typical 1 nF gate capacitance. Layout must minimize trace inductance; exceeding 2 nF total gate load risks overshoot and shoot-through due to limited current slew rate.

What is the impact of omitting the external 47 μF bulk capacitor on VCC?

Omitting the 47 μF bulk capacitor causes VCC ripple to exceed 2 V peak-to-peak during load transients, triggering repeated UVLO cycling (VCCL/VCCH hysteresis) and disrupting regulation. The 0.1 μF ceramic alone cannot sustain gate drive current; this leads to intermittent shutdown and output voltage collapse under dynamic loads.

Does the internal slope compensation vary with switching frequency?

Yes - slope compensation is dynamically scaled to switching frequency: at 100 kHz it is 42 mV/μs (typ.), decreasing linearly to ~7 mV/μs at 600 kHz. This maintains consistent subharmonic oscillation margin across the full programmable range without requiring external adjustment.

How is burst-mode frequency determined, and can it be adjusted externally?

Burst-mode frequency is governed solely by FB voltage hysteresis (VBURL = 0.50 V, VBURH = 0.73 V) and output capacitor discharge rate - it is not user-adjustable. Typical burst rates range from 10 Hz to 200 Hz depending on output capacitance and load; adding series resistance to FB divider has negligible effect due to internal pull-up dominance.

Is the NC pin (Pin 3) required to be left floating, or may it be tied to GND?

Pin 3 (NC) must remain unconnected - neither tied to GND nor routed. MPS specifies zero internal connection; grounding it risks introducing noise coupling into adjacent pins (FSET and VCC) due to shared bond-wire inductance and substrate coupling in the SOIC8 die layout.