Monolithic Power Systems Inc. MP1921HR-A-LF-Z

Overview

MP1921HR-A-LF-Z from Monolithic Power Systems is a high-frequency, 100V half-bridge gate driver IC for N-channel MOSFETs, delivering 2.5A peak source/sink current per channel, <5ns high-side/low-side propagation matching, and integrated bootstrap diode in a 4×4mm QFN10 package. It enables telecom power supplies and active-clamp forward converters requiring precise timing and robust UVLO protection.

For engineers reviewing the MP1921HR-A-LF-Z datasheet, MP1921HR-A-LF-Z pinout, MP1921HR-A-LF-Z application, or MP1921HR-A-LF-Z equivalent, key selection criteria include bootstrap voltage range (120V), propagation delay (16ns typ.), rise/fall times (12ns/9ns into 1nF), TTL-compatible inputs, and dual independent UVLO thresholds (VDD: 8.1V, BST–SW: 7.1V).

Technical Context

The MP1921HR-A-LF-Z implements independent high-side and low-side drivers with level-shifted floating architecture, enabling operation with SW node voltages up to +100V and slew rates <50V/ns. Its internal bootstrap diode eliminates external diode requirement while supporting VBST up to 120V relative to SW.

UVLO circuitry monitors both VDD (7.7–8.5V threshold) and BST–SW (6.7–7.5V threshold) independently, forcing DRVH and DRVL low during undervoltage conditions. Input logic is TTL-compatible with internal 185kΩ pull-down resistors on INH/INL, ensuring defined states during controller reset.

Key Specifications

Pinout & Package

MP1921HR-A-LF-Z uses a thermally enhanced 4×4mm QFN10 package with exposed thermal pad (pin 7 connected to VSS). The 10-pin layout supports compact high-density PCB layouts while maintaining isolation between high-voltage SW node and logic inputs.

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 and MP1921HS-A-LF-Z, the MP1921HR-A-LF-Z offers optimal thermal performance (θ_JA = 47°C/W) and routing flexibility via two NC pins, making it ideal for high-reliability, high-power-density telecom and avionics power modules.

Availability

MP1921HR-A-LF-Z is available at Aetrix Electronics and suitable for telecom power supplies, avionics DC-DC converters, and two-switch forward converters requiring stable component supply, RoHS-compliant packaging, and long-term lifecycle support.

Supply support for MP1921HR-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 and global manufacturing partnerships.

The MP1921A series targets high-frequency, high-voltage power conversion systems, emphasizing timing precision, integrated bootstrap functionality, and robust fault protection for mission-critical power architectures.

FAQ

What is the maximum allowable SW node voltage for MP1921HR-A-LF-Z?

The absolute maximum SW voltage is +105V for <100ns transients and +100V continuously. Operation at 100V DC is supported per recommended operating conditions, with derating required above that level to maintain reliability and avoid exceeding V_BST–V_SW limits.

Does MP1921HR-A-LF-Z require an external bootstrap diode?

No. The device integrates a bootstrap diode with VF = 0.9V at 100mA and dynamic resistance of 2.5Ω, eliminating the need for an external Schottky diode and reducing PCB area and BOM count in half-bridge designs.

How is shoot-through prevented in MP1921HR-A-LF-Z applications?

Shoot-through is prevented by externally inserting dead time between INH and INL signals - the IC itself does not generate dead time. Its <5ns propagation matching ensures minimal timing skew, allowing precise external dead-time control to avoid simultaneous high-side/low-side conduction.

What is the purpose of the two NC pins in the QFN10 package?

Pins 5 and 10 are internally unconnected and serve mechanical and routing purposes: they provide additional spacing for high-voltage isolation between SW and logic pins, and allow flexible PCB layout for thermal pad anchoring and signal escape routing without compromising creepage/clearance.

Can MP1921HR-A-LF-Z drive 1000pF gate loads at 1MHz?

Yes. With 12ns/9ns rise/fall times into 1nF and 2.5A peak drive strength, it supports 1000pF loads at 1MHz while maintaining <10ns propagation delay variation. Layout-dependent parasitics must remain low to preserve timing accuracy.

Is the exposed thermal pad on MP1921HR-A-LF-Z electrically connected?

Yes - the exposed pad is internally connected to VSS and must be soldered to a dedicated VSS copper pour. It serves as both primary thermal path and electrical ground return; omitting this connection degrades θ_JA by >25°C/W and risks thermal shutdown under load.

What happens during bootstrap capacitor under-voltage?

When (VBST–SW) drops below 6.7V, the high-side UVLO triggers and forces DRVH low. This prevents weak or undefined high-side gate drive, avoiding partial turn-on and potential MOSFET failure due to excessive conduction losses.