NXP Semiconductors MC34931SEKR2

Overview

MC34931SEKR2 from NXP Semiconductors is a monolithic 5.0 A H-Bridge Power IC in a thermally enhanced 32-pin SOICW-EP package, designed for low-voltage DC brushed and servo motor control up to 36 V supply. It integrates dual half-bridge totem-pole outputs, internal charge pump, PWM current regulation (20 kHz max), load current feedback (0.24% proportional), and fault reporting via open-drain SF pin. Used in robotics, POS kiosks, and security camera pan/tilt systems.

For engineers reviewing the MC34931SEKR2 datasheet, MC34931SEKR2 pinout, MC34931SEKR2 application, or MC34931SEKR2 equivalent, this page delivers verified technical context, real-world design meaning of key specs, validated pin functions, confirmed alternative options, and supply-chain support details specific to the MC34931SEKR2 - not generic H-bridge assumptions.

Technical Context

The MC34931SEKR2 implements constant-off-time PWM current regulation with 20.5 µs typical blanking time and 20.5 µs typical constant-OFF time, enabling precise peak-current limiting at up to 20 kHz switching frequency. Its SMARTMOS process integrates high-side and low-side MOSFETs with 235 mΩ max R_DS(on) per FET at 150 °C junction temperature.

It features dual independent logic inputs (IN1/IN2) for full H-bridge polarity control, two disable inputs (D1 and EN/D2) supporting tri-state operation and <20 µA sleep mode, plus analog FB output for microcontroller ADC monitoring and open-drain SF flag reporting undervoltage, overcurrent, and overtemperature faults.

Key Specifications

Pinout & Package

MC34931SEKR2 uses a 32-pin SOICW-EP (exposed pad) package optimized for thermal dissipation. The exposed pad (EP) must be soldered to a low-impedance GND plane to achieve R_θJC < 1.0 °C/W. Power pins (VPWR, PGND) and output pins (OUT1, OUT2) are distributed across multiple pins to minimize trace inductance and resistive loss.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar H-bridge motor driver applications.

Compared with MC33886 and TB9051FTG, the MC34931SEKR2 uniquely balances 20 kHz PWM capability, integrated 0.24% current feedback, and industrial temperature range in a thermally optimized SOICW-EP package - making it optimal for cost-sensitive, noise-sensitive, and firmware-monitored motor control.

Availability

MC34931SEKR2 is available at Aetrix Electronics and suitable for robotics actuation, POS/kiosk motor control, and security camera pan/tilt systems requiring stable component supply, long-lifecycle assurance, and traceable sourcing from authorized NXP channels.

Supply support for MC34931SEKR2 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

NXP Semiconductors is a global semiconductor leader focused on secure connectivity solutions for automotive, industrial, and IoT applications, with deep expertise in power management and motor control ICs.

The MC34931SEKR2 belongs to NXP's SMARTMOS H-bridge product line, engineered specifically for robust, thermally efficient DC motor control in space-constrained industrial equipment - emphasizing integrated protection, analog feedback, and ease of MCU interfacing.

FAQ

What is the maximum PWM frequency supported by the MC34931SEKR2?

The MC34931SEKR2 supports PWM frequencies up to 20 kHz, as confirmed in Table 5 of the official NXP datasheet (Rev. 4.0, 2016). This is specific to the SEK variant (e.g., MC34931SEKR2), unlike the base MC34931EK which is limited to 11 kHz. Operating above 20 kHz may cause incomplete high-side MOSFET enhancement and increased conduction losses. The MC34931SEKR2 achieves this via optimized gate drive and charge pump timing.

How does the current feedback (FB pin) function in the MC34931SEKR2?

The FB pin on the MC34931SEKR2 provides a ground-referenced current mirror output sourcing 0.24% of the high-side load current (e.g., 1.2 mA at 5.0 A). It is intended for connection to a microcontroller's ADC via a 270 Ω resistor to generate a proportional voltage. Accuracy is better than 20% from 0.5 A to 6.0 A, and the pin requires no external bias - the MC34931SEKR2 internally generates the mirrored current based on actual MOSFET conduction.

What thermal management is required for reliable operation of the MC34931SEKR2 at 5.0 A continuous current?

To sustain 5.0 A continuous output current, the MC34931SEKR2 requires PCB-level thermal design achieving R_θJA < 5.0 °C/W at 70 °C ambient, per NXP's thermal guidelines. This mandates full-soldering of the exposed pad (EP) to a large internal/external GND copper area, short low-impedance connections for all VPWR and PGND pins, and use of thermal vias under the EP. Without this, junction temperature exceeds 150 °C, triggering current foldback or shutdown.

Can the MC34931SEKR2 be used in sleep mode with zero external components beyond the MCU interface?

Yes - the MC34931SEKR2 enters sleep mode with EN/D2 pulled LOW, drawing <20 µA typical supply current (IPWR(SLEEP)), as verified in Table 4. No external capacitors or resistors are required beyond the mandatory CCP capacitor (30–100 nF) and SF pull-up (≤7.0 V). All logic inputs (IN1, IN2, D1) may float due to internal pull-up/pull-down networks, making the MC34931SEKR2 compatible with minimalist MCU GPIO control schemes.

What fault conditions trigger the SF (Status Flag) pin on the MC34931SEKR2, and how is it cleared?

The SF pin on the MC34931SEKR2 goes LOW for three confirmed fault conditions: undervoltage (VPWR < 4.15 V), overcurrent (load ≥6.5 A or short-circuit ≥11 A), or overtemperature (T_J ≥175 °C). Clearing requires toggling either D1 or EN/D2 (e.g., LOW→HIGH→LOW) or cycling VPWR - simply removing the fault condition is insufficient. This latched behavior ensures firmware detects and handles faults before resuming operation.