Monolithic Power Systems Inc. HFC0300HS-LF-P

Overview

HFC0300HS-LF-P from Monolithic Power Systems is a variable off-time, current-mode flyback controller IC for AC/DC power supplies operating from 85–265VAC input. It implements fixed-peak-current control with frequency foldback, active burst mode, internal 700V HV startup, and integrated protections including OVP (24V latch), thermal shutdown (150°C), and short-circuit protection. It targets high-efficiency, low-noise offline SMPS in portable chargers and standby supplies.

For engineers reviewing the HFC0300HS-LF-P datasheet, HFC0300HS-LF-P pinout, HFC0300HS-LF-P application, or HFC0300HS-LF-P equivalent, key selection criteria include its SOIC-7 package, 200ns leading-edge blanking, COMP-based burst threshold (3.1–3.2V), FSET capacitor-controlled max frequency (65kHz typical), and VCC UVLO hysteresis (8.2V to 11.7V).

Technical Context

The HFC0300HS-LF-P uses a fixed-peak-current architecture where switching frequency decreases linearly with load reduction, enabling light-load efficiency optimization. Its oscillator is voltage-controlled via the COMP pin, with FSET capacitor charging at 28μA and discharging after reaching 0.88V - generating a programmable max frequency up to ~65kHz.

Protection logic is tightly coupled to analog monitoring: VCC OVP latches at >24V with 20μs filtering; overload triggers after 74ms delay when COMP drops below 0.85V; SCP activates at CS ≥1.0V; thermal shutdown engages at 150°C with 25°C hysteresis. All fault responses except OVP auto-restart.

Key Specifications

Pinout & Package

Package: SOIC-7 (surface-mount, 7-pin, standard pitch). Pin 8 is HV (high-voltage startup input); pin 3 is GND; pin 6 is VCC (regulated supply input); pin 1 is DRV (MOSFET gate driver output); pin 2 is CS (current-sense input); pin 4 is COMP (feedback error amplifier output); pin 5 is FSET (frequency-setting capacitor connection).

Key Features

Applications

Equivalent & Alternatives

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

Compared with UCC28631DR and ICE2QS03G, the HFC0300HS-LF-P uniquely combines internal 700V HV startup, COMP-based burst mode (3.1–3.2V), and peak-current compression - delivering lowest no-load loss and quietest transformer operation in universal-input flyback designs.

Availability

HFC0300HS-LF-P is available at Aetrix Electronics and suitable for battery chargers, standby power supplies, universal-input SMPS, and low-noise industrial adapters requiring stable component supply, RoHS-compliant packaging, and long-term lifecycle support.

Supply support for HFC0300HS-LF-P 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 over 20 years of expertise in DC/DC, AC/DC, and motor drivers.

The HFC0300 belongs to MPS's offline flyback controller product line, designed specifically for high-efficiency, low-EMI, and ultra-low standby-power AC/DC conversion in consumer and industrial power supplies.

FAQ

What is the purpose of the HV pin on the HFC0300HS-LF-P?

The HV pin provides a 700V-rated high-voltage input that sources a 2mA startup current to charge the VCC capacitor before the auxiliary winding takes over. This eliminates the need for an external high-voltage startup resistor, improving system reliability and reducing component count in universal-input flyback designs.

How does the HFC0300HS-LF-P achieve low no-load power consumption?

It enters active burst mode when the COMP voltage exceeds 3.2V, disabling switching cycles until COMP falls below 3.1V. Combined with frequency foldback and internal low-quiescent-current design, this reduces no-load power loss to 74.4mW at 90VAC and <85mW at 265VAC - meeting stringent global energy regulations.

What is the function of the FSET pin and how is it used in design?

The FSET pin connects to a capacitor charged at 28μA; its voltage is compared to a 0.88V internal threshold to set maximum switching frequency (e.g., 65kHz with 330pF). It also determines the overload protection timer duration (74ms at 330pF), making it central to both performance tuning and fault response calibration.

Does the HFC0300HS-LF-P require external ramp compensation?

Yes - when operating in continuous conduction mode (CCM) with duty cycle >0.5, external ramp compensation is required to prevent subharmonic oscillation. The recommended circuit uses a resistor divider and capacitor from DRV to CS, with time constant selected to exceed the switching period for linear ramp generation.

How does the HFC0300HS-LF-P handle over-voltage protection on the VCC pin?

It monitors VCC through a 20μs RC-filtered comparator. If VCC exceeds 24V (typical), the controller enters a latched-off state and remains disabled until VCC drops below 3.0V - requiring main input cycling. This differs from auto-restarting protections (OTP, SCP, OLP) and ensures robust safety against sustained overvoltage events.

What is the significance of the 200ns leading-edge blanking on the CS pin?

The 200ns LEB disables the current-sense comparator immediately after MOSFET turn-on to ignore parasitic ringing caused by transformer leakage inductance and layout capacitance. This prevents false current-limit triggering and ensures accurate peak-current detection for stable regulation across line/load variations.