Monolithic Power Systems Inc. MP1921HQ-A-LF-Z

Overview

MP1921HQ-A-LF-Z from Monolithic Power Systems is a high-frequency, 100V half-bridge gate driver IC for N-channel MOSFETs, featuring independently controlled high-side and low-side outputs with <5ns propagation matching, 16ns typical propagation delay, and integrated bootstrap diode. It delivers 2.5A peak sink/source current and supports 120V BST voltage range in telecom power supplies and DC motor drivers.

For engineers reviewing the MP1921HQ-A-LF-Z datasheet, MP1921HQ-A-LF-Z pinout, MP1921HQ-A-LF-Z application, or MP1921HQ-A-LF-Z equivalent, key selection criteria include bootstrap diode integration, UVLO thresholds on both VDD and BST-SW rails, 12ns/9ns rise/fall times into 1nF load, TTL-compatible inputs, and SOIC8E/QFN8/QFN9/QFN10 package options.

Technical Context

The MP1921HQ-A-LF-Z implements dual independent level-shifted drivers with matched timing paths to minimize shoot-through risk in hard-switched topologies. Its internal bootstrap diode eliminates external diode requirement while supporting up to 120V BST voltage swing relative to SW node.

UVLO circuitry monitors both VDD (7.7–8.5V threshold) and BST–SW (6.7–7.5V threshold) with 0.5V/0.55V hysteresis, forcing DRVH and DRVL low during undervoltage conditions. Input logic accepts TTL-level signals with 185kΩ internal pull-down resistors on INH and INL.

Key Specifications

Pinout & Package

MP1921HQ-A-LF-Z is packaged in a 3×3mm QFN-8 with exposed thermal pad. Pin 1 is marked by index area; exposed pad must be connected to VSS for thermal and electrical integrity.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar half-bridge gate driver applications.

Compared with MP1921HQ-A-LF-Z, MP1921HS-A trades thermal performance for legacy through-hole compatibility, while MP1921HR-A improves thermal resistance at the cost of larger footprint-making the QFN8 variant optimal for balanced size, thermal, and cost requirements in mid-power applications.

Availability

MP1921HQ-A-LF-Z is available at Aetrix Electronics and suitable for telecom power supplies, avionics DC-DC converters, and DC motor drivers requiring stable component supply, RoHS-compliant packaging, and consistent QFN8 sourcing.

Supply support for MP1921HQ-A-LF-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 across Asia and North America.

The MP1921A product line targets high-frequency, high-voltage half-bridge gate driving in isolated and non-isolated DC-DC converters, emphasizing timing precision, integrated bootstrap functionality, and robust UVLO protection.

FAQ

What is the maximum allowable SW node voltage slew rate for reliable MP1921HQ-A-LF-Z operation?

The datasheet specifies a maximum SW slew rate of <50V/ns to prevent false triggering of internal level shifters and ensure stable high-side driver operation. Exceeding this rate may cause erratic DRVH behavior or premature UVLO activation due to capacitive coupling into BST or VDD rails.

Can MP1921HQ-A-LF-Z drive P-channel high-side MOSFETs?

No. The MP1921HQ-A-LF-Z is designed exclusively for N-channel high-side MOSFETs using bootstrap-based high-side drive. Its DRVH output is a source-follower configuration referenced to SW, making it incompatible with P-channel devices requiring gate-to-source negative bias.

Is an external bootstrap diode required when using MP1921HQ-A-LF-Z?

No. The device integrates a low-forward-voltage bootstrap diode (VF = 0.5V @ 100µA), eliminating the need for an external diode. This reduces component count, PCB area, and potential failure points in high-density power designs.

How does the MP1921HQ-A-LF-Z handle shoot-through prevention?

It does not include built-in dead-time generation. Shoot-through prevention relies entirely on externally controlled timing of INH and INL signals. Users must implement sufficient dead time between INH low and INL low (or vice versa) in their PWM controller to avoid simultaneous conduction.

What is the recommended minimum bootstrap capacitor value for 100V operation?

For 100V V_SW operation at 500kHz, a minimum 100nF ceramic capacitor rated ≥100V is recommended between BST and SW pins. Larger values (e.g., 220nF) improve voltage hold-up during long low-side on-times and reduce ripple-induced timing jitter.

Does MP1921HQ-A-LF-Z support 3.3V logic inputs?

No. Its INH and INL inputs require TTL-compatible thresholds: logic high must be ≥2.0V (typ. 2.4V), and logic low must be ≤1.4V. A 3.3V CMOS signal meets the high threshold but may exceed absolute max ratings if VDD < 3.3V; level-shifting is advised for mixed-voltage systems.

What thermal derating applies to the QFN8 package above 70°C ambient?

With θ_JA = 50°C/W, power dissipation must be linearly derated above 25°C ambient. At 70°C, maximum continuous power drops to (150°C − 70°C) / 50°C/W = 1.6W. For sustained 2.5A drive, ensure board copper area and airflow maintain junction temperature ≤125°C.