Monolithic Power Systems Inc. MP1921HS-A-LF

Overview

MP1921HS-A-LF 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 per channel and supports telecom half-bridge power supplies operating up to 100V input.

For engineers reviewing the MP1921HS-A-LF datasheet, MP1921HS-A-LF pinout, MP1921HS-A-LF application, or MP1921HS-A-LF equivalent, key selection criteria include bootstrap voltage range (120V), UVLO thresholds (7.1V/6.7V), TTL-compatible inputs, SOIC-8 package thermal resistance (96°C/W), and dead-time–sensitive dual-input control architecture.

Technical Context

The MP1921HS-A-LF implements a level-shifted floating driver architecture with independent INH/INL inputs, enabling precise timing control of high-side and low-side MOSFETs in hard-switched topologies. Its internal bootstrap diode eliminates external diode requirements while maintaining VBST–SW up to 120V.

UVLO protection operates separately on VDD (7.7–8.5V threshold) and BST–SW (6.7–7.5V threshold), forcing both DRVH and DRVL low during undervoltage conditions. Propagation delays are matched within ±2.5ns (typical 1ns), supporting >1MHz switching in DC-DC converters without shoot-through risk when paired with adequate external dead-time control.

Key Specifications

Pinout & Package

MP1921HS-A-LF is packaged in RoHS-compliant SOIC-8 (3.9mm × 4.9mm, 1.27mm pitch) with exposed thermal pad connected to VSS. Package thermal resistance θ_JA is 96°C/W, requiring PCB copper pour under the exposed pad for reliable 1.3W continuous dissipation at 25°C ambient.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MP1921HQ-A, the MP1921HS-A-LF trades thermal efficiency for ease of hand-soldering and legacy SOIC compatibility; versus IRS21844SPbF, it offers tighter timing, integrated bootstrap, and lower propagation delay-critical for MHz-class telecom and avionics converters.

Availability

MP1921HS-A-LF is available at Aetrix Electronics and suitable for telecom half-bridge power supplies, avionics DC-DC converters, and two-switch forward converters requiring stable component supply, RoHS compliance, and long-term industrial lifecycle support.

Supply support for MP1921HS-A-LF 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 MP1921A product line targets high-frequency, high-voltage DC-DC conversion in telecom, aerospace, and industrial power systems, emphasizing timing precision, integrated features, and rugged operation across extended temperature ranges.

FAQ

What is the maximum allowable SW node voltage slew rate for MP1921HS-A-LF?

The datasheet specifies a maximum SW slew rate of <50V/ns under recommended operating conditions. Exceeding this may cause false triggering of the level shifter or premature UVLO activation due to coupling into BST or VDD nodes. Layout best practices-including minimized SW loop area and tight bootstrap capacitor placement-must be followed to maintain stability at high dV/dt.

Does MP1921HS-A-LF require an external bootstrap diode?

No. MP1921HS-A-LF integrates a low-forward-voltage bootstrap diode (VF = 0.5V @ 100µA) that eliminates the need for an external diode. This reduces component count, PCB area, and potential failure points in high-reliability applications such as avionics and telecom infrastructure.

How does the dual UVLO function protect the system?

The MP1921HS-A-LF monitors both VDD (threshold 7.7–8.5V) and BST–SW (threshold 6.7–7.5V) independently. If either supply falls below its UVLO threshold, the corresponding driver output (DRVH or DRVL) is forced low, preventing partial turn-on of MOSFETs and avoiding shoot-through or thermal runaway during brownout or bootstrap capacitor discharge.

Can INH and INL be driven by the same PWM signal?

Yes, but only in topologies where both MOSFETs switch simultaneously-such as two-switch forward converters. In half-bridge or active-clamp forward configurations, independent INH/INL timing with intentional dead time is mandatory to prevent shoot-through. The device does not include internal dead-time generation; external controller coordination is required.

What is the purpose of the exposed pad on the SOIC-8 package?

The exposed pad on MP1921HS-A-LF's SOIC-8 package is electrically and thermally connected to VSS. It must be soldered to a PCB copper pour tied to the system ground plane to achieve the specified θ_JA = 96°C/W and dissipate up to 1.3W continuously. Omitting this connection risks thermal shutdown above 85°C ambient.

Is MP1921HS-A-LF compatible with 3.3V logic controllers?

No. MP1921HS-A-LF inputs are TTL-compatible (VIH ≥ 2.4V, VIL ≤ 1.4V), not 3.3V CMOS. Driving INH/INL directly from a 3.3V microcontroller is acceptable only if its VOH ≥ 2.4V and VOL ≤ 1.4V under load. For guaranteed compatibility with 3.3V logic, a level-shifter or buffer with appropriate thresholds is recommended.