Monolithic Power Systems Inc. HF920AGS-P

Overview

HF920AGS-P from Monolithic Power Systems is a monolithic 900V flyback switching regulator IC integrating a high-voltage power MOSFET (R_DS(ON) = 15 Ω @ 25°C), peak-current-mode control, programmable switching frequency up to 150 kHz, and active burst mode enabling <30 mW no-load consumption. It delivers up to 10 W output power at 230 VAC ±15% in SOIC14-11 package for AC/DC power supplies in smart meters and industrial controls.

For engineers reviewing the HF920AGS-P datasheet, HF920AGS-P pinout, HF920AGS-P application, or HF920AGS-P equivalent, key selection criteria include its integrated 900V MOSFET breakdown voltage, PRO-pin programmable input under-voltage/over-voltage protection thresholds, internal slope compensation for stable CCM operation, and ±3.5% frequency jittering for EMI reduction in PLC-critical environments.

Technical Context

The HF920AGS-P implements peak-current-mode control with internal slope compensation, enabling stable continuous conduction mode (CCM) operation even at duty cycles >50%. Its proprietary 900V silicon process integrates the power MOSFET and thermal sensor on-die, delivering precise over-temperature protection at 150°C with 30°C hysteresis.

Switching frequency is set externally via a resistor on FSET (1.25 V reference), while frequency jittering spreads spectral energy across ±3.5% of f_S over a 256-cycle carrier. Protection logic includes time-based overload detection (8192 cycles), short-circuit shutdown via S-pin threshold (1.5 V), and dual-level PRO-pin monitoring for external UVP/OVP.

Key Specifications

Pinout & Package

HF920AGS-P is packaged in SOIC14-11, a 14-pin surface-mount package with exposed thermal pad (GND-connected) and 7 mm × 8.7 mm footprint optimized for high-voltage isolation and thermal dissipation in offline SMPS designs.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MP023GS-Z and LNK364PG, HF920AGS-P uniquely combines 900 V integration, PRO-pin programmability, and frequency jittering-enabling robust operation on poor AC grids while meeting stringent EMI limits for PLC coexistence, at the cost of higher pin count and external component dependency.

Availability

HF920AGS-P is available at Aetrix Electronics and suitable for smart meter power supplies, industrial PLC modules, and building automation gateways requiring stable component supply across extended product lifecycles and global regulatory certifications.

Supply support for HF920AGS-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 design centers in the US, China, and Taiwan, and manufacturing partners qualified to AEC-Q200 and ISO 9001 standards.

The HF920A product line targets high-reliability offline AC/DC conversion for utility-grade equipment, emphasizing integrated high-voltage capability, ultra-low standby power, and system-level protection programmability for harsh grid environments.

FAQ

What is the maximum continuous output power achievable with HF920AGS-P at 230 VAC ±15%?

The HF920AGS-P delivers up to 10 W continuous output power at 230 VAC ±15% when mounted on a SOIC14-11 test board with 2.5 cm² GND copper pour and operated within TJ ≤ 125°C. This assumes single-output configuration (12.5 V), BCM operation at minimum input, and proper heatsinking per MPS Application Note AN-105.

How does the PRO pin implement input under-voltage protection?

The PRO pin detects input under-voltage via an external resistor divider from the bulk DC bus. When PRO voltage drops below 0.25 V (typical), the IC initiates shutdown after 20 μs delay. Recovery occurs automatically when PRO rises above 0.25 V + 0.2 V hysteresis, enabling restart once input voltage recovers to ≥59 VDC as verified in typical performance waveforms.

Can HF920AGS-P operate in discontinuous conduction mode (DCM)?

Yes - HF920AGS-P supports DCM, boundary conduction mode (BCM), and continuous conduction mode (CCM) depending on transformer design and load. Its internal slope compensation stabilizes current-mode control across all modes, and burst mode activates automatically below ~10% load to maintain regulation while minimizing switching loss.

What is the purpose of the dual leading-edge blanking (LEB) timers?

HF920AGS-P uses two independent LEB timers: t_LEB1 = 385 ns blocks current-sense comparator during MOSFET turn-on to reject primary ringing, while t_LEB2 = 350 ns disables short-circuit protection comparator separately. This prevents false OCP triggering during transient overloads while preserving fast SCP response to hard shorts.

Is external soft-start required when using HF920AGS-P?

No - HF920AGS-P includes an internal soft-start circuit with 6.7 ms typical duration. During startup, it gradually increases the peak current limit and ramps switching frequency from 20% to 100% of the programmed value, eliminating inrush stress on the MOSFET and secondary diode without external components.

How does frequency jittering reduce EMI in HF920AGS-P?

HF920AGS-P applies ±3.5% frequency deviation over a 256-cycle carrier period, spreading spectral energy across a bandwidth instead of concentrating it at discrete harmonics. This lowers peak radiated emissions by 10–15 dB, allowing smaller Y-capacitors and fewer common-mode chokes in the input EMI filter per EN 55032 Class B testing.

What thermal derating applies to HF920AGS-P in SOIC14-11 package?

In SOIC14-11, HF920AGS-P has θ_JA = 70°C/W on a 4-layer PCB. At 50°C ambient, maximum continuous power dissipation is limited to 1.78 W before junction temperature reaches 150°C. For 10 W output, thermal design must ensure effective heat transfer from the exposed GND pad to ≥2.5 cm² copper area per datasheet layout guidelines.