Allegro MicroSystems UDN2916LBTR

Overview

UDN2916LBTR from Allegro MicroSystems is a dual full-bridge PWM motor driver IC designed to control both windings of bipolar stepper motors or bidirectionally drive two DC motors. It sustains 45 V motor supply voltage, delivers 750 mA continuous output current per bridge, and features internal PWM current control with selectable 0%/33%/67%/100% current limits via logic inputs I₀/I₁ - used in industrial motion control systems requiring precise winding current regulation.

For engineers reviewing the UDN2916LBTR datasheet, UDN2916LBTR pinout, UDN2916LBTR application, or UDN2916LBTR equivalent, key selection considerations include its 24-pin batwing SOICW (LB) package thermal performance (θ_JA = 55°C/W), integrated clamp/flyback diodes, low 1.8 V total saturation voltage at 500 mA, and compatibility with microprocessor-controlled half-step and micro-stepping sequences.

Technical Context

The UDN2916LBTR implements two independent H-bridge outputs with internal PWM current regulation using external RC timing components (RT/CT) to set fixed off-time (e.g., 46 μs typical with 56 kΩ/820 pF). Each bridge includes PHASE-controlled direction switching with ~2 μs internally generated dead time to prevent shoot-through.

Current limiting is achieved via V_REF/R_SENSE feedback with four discrete trip thresholds (9.5–34.5 A/V_REF scaling) selected by I₀/I₁ logic levels; thermal shutdown activates at 170°C junction temperature and recovers at 145°C.

Key Specifications

Pinout & Package

The UDN2916LBTR is supplied in a 24-pin surface-mount wide SOIC (SOICW) package with two pairs of fused batwing leads (Pins 6/7 and 18/19) acting as thermally enhanced ground/power tabs for improved power dissipation (θ_JA = 55°C/W on single-layer board).

Key Features

Applications

Equivalent & Alternatives

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

Compared with UDN2916LBTR, the A4970 offers higher current and digital diagnostics but demands more complex layout and firmware integration, while the DRV8825 simplifies microstepping implementation at the expense of analog current tuning flexibility and thermal robustness in high-ambient environments.

Availability

UDN2916LBTR is available at Aetrix Electronics and suitable for industrial motion control, medical device actuation, and automotive HVAC subsystems requiring stable component supply despite its Pre-End-of-Life status.

Supply support for UDN2916LBTR 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

Allegro MicroSystems is a U.S.-based designer and manufacturer of high-performance Hall-effect sensors, motor driver ICs, and power ICs for automotive and industrial markets.

The UDN2916 family was developed specifically for cost-effective, thermally robust bipolar stepper and dual-DC motor control in space-constrained industrial and medical equipment - emphasizing analog current regulation and integrated protection.

FAQ

What is the maximum continuous output current supported by the UDN2916LBTR?

The UDN2916LBTR supports 750 mA continuous output current per bridge under specified thermal conditions (T_A ≤ 105°C, θ_JA = 55°C/W). This rating assumes proper PCB copper area connected to batwing leads and adequate airflow. Peak current capability reaches 1.0 A, but duration must be limited to avoid exceeding T_J(max) = 150°C. The UDN2916LBTR datasheet specifies this value in Absolute Maximum Ratings and Electrical Characteristics tables.

Does the UDN2916LBTR require external flyback diodes for inductive load protection?

No, the UDN2916LBTR integrates clamp diodes and flyback diodes within each H-bridge - eliminating the need for eight external diodes typically required in discrete MOSFET-based drivers. These internal diodes handle inductive transients from stepper windings or DC motors, provided the V_CE(sus) rating of 45 V is not exceeded. The UDN2916LBTR design intentionally embeds this protection to reduce system-level component count and layout complexity.

How does the UDN2916LBTR implement PWM current control without an external oscillator?

The UDN2916LBTR uses an internal monostable multivibrator triggered by current-sense comparator output to generate fixed off-time PWM. When sensed voltage across R_SENSE reaches V_REF/10, the comparator triggers the monostable, turning off the source driver for a duration set by external R_T/C_T components. This architecture eliminates need for external clock sources while enabling precise current regulation. The UDN2916LBTR's EP-007B schematic shows this self-timed chopper topology.

Can the UDN2916LBTR operate with a 3.3 V logic supply?

No, the UDN2916LBTR requires a minimum V_CC of 4.75 V and maximum of 5.25 V for guaranteed logic-level compatibility - it is not rated for 3.3 V operation. Inputs I₀, I₁, PHASE, and PWM have V_IN(1) ≥ 2.4 V and V_IN(0) ≤ 0.8 V thresholds, which align with 5 V TTL/CMOS levels. Using 3.3 V may result in undefined behavior or failure to recognize logic HIGH states. The UDN2916LBTR datasheet explicitly defines V_CC range in Absolute Maximum Ratings and Electrical Characteristics.

What thermal management guidance applies specifically to the UDN2916LBTR's LB package?

The UDN2916LBTR's LB package uses fused batwing leads (Pins 6/7 and 18/19) as thermal pathways - connecting these pins to ≥6 cm² of 2 oz copper on the PCB improves power dissipation by 20–30%. Thermal resistance is specified as θ_JA = 55°C/W on single-layer board; adding copper area lowers effective θ_JA. Junction temperature should be kept below 125°C for reliability, calculated as T_J = T_TAB + (2 × I_LOAD × V_F × 6°C/W). The UDN2916LBTR application notes detail this method in Section "Thermal Considerations".