UDN2987LWTR-6-T - 8-Ch Source Driver, 350mA, 35V SOIC-20 | Allegro
MPN: UDN2987LWTR-6-T ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $2.19 | $2.19 |
| 10 | $1.97 | $19.70 |
| 100 | $1.75 | $175.00 |
| 500 | $1.55 | $775.00 |
| 1,000 | $1.38 | $1,380.00 |
UDN2987LWTR-6-T Overview
What is an 8-channel source driver? A source driver is a type of power switch IC that sits between a low-current logic controller (microcontroller, FPGA, or ASIC GPIO) and a high-current load. Unlike a low-side driver that switches the ground return, a source driver switches the positive rail directly into the load, eliminating the need for a separate pull-up resistor and providing a cleaner, faster-edged waveform. Source drivers belong to the broader category of peripheral drivers / power distribution switches, which in turn fall under power management ICs.
Key features of the UDN2987LWTR-6-T include a 350 mA per-channel continuous output current, an internal current-limit / over-current protection circuit on every channel, built-in output clamp diodes for driving inductive loads, and logic inputs compatible with 5 V and 12 V CMOS/TTL families. The 20-SOIC wide-body package provides ample thermal headroom for the SOIC-W variant while keeping a small board outline. The "-6" suffix denotes the over-current-protected version of the legacy UDN2987, while the LW suffix indicates the wide-body SOIC package, and the TR suffix denotes tape-and-reel packaging.
Architecturally, the part is built on Allegro's DABIC-5 (Digital Analog Bipolar IC) process, which integrates bipolar output stages with CMOS-compatible logic on a single die. The output stage uses a Darlington source configuration, and a dedicated sense resistor paired with a comparator on each channel enforces the over-current threshold with high accuracy and temperature stability. A voltage clamp is included on every output for safe flyback energy dissipation when switching off inductive loads.
Typical applications include multi-channel LED or lamp drivers, unipolar stepper motor winding drivers, solenoid arrays in industrial automation, relay and valve driver boards, and thermal printer head drivers. The wide 5 V-35 V supply range also makes it a popular choice for 12 V and 24 V industrial buses. Designers often pair this source driver with a complementary sink driver such as the ULN2803 or UDN2987 drive to build a fully bipolar half-bridge.
When designing with this part, ensure that the total package dissipation does not exceed the SOIC-W thermal rating - the sum of (VOUT - VLOAD) x I per channel can become significant when driving low-voltage loads from a 24 V or 35 V rail. Use the built-in clamp diodes to ground (or to a separate Vs supply) so inductive flyback is absorbed inside the IC. Decouple VCC close to the device with at least 0.1 uF, and tie unused inputs to ground for noise immunity.
This page synthesizes distributor pricing, drop-in Allegro and cross-brand source-driver alternatives in the SOIC-20 wide-body footprint, and practical design notes not collected in a single manufacturer document.
Drop-in alternatives for UDN2987LWTR-6-T — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with UDN2987LWTR-6-T (same form factor and footprint) — differing in Package, Function, Output Current per Channel, Part Number, Process Technology.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
UDN2987LW-6-T
✅ Drop-In📋 Reference alternative (not in catalog)
UDN2987A-6-T
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
TD62083AFG
✅ Drop-In📋 Reference alternative (not in catalog)
TD62083APG
✅ Drop-In📋 Reference alternative (not in catalog)
NJM2682V-TE1
✅ Drop-In📋 Reference alternative (not in catalog)
UDN2987LWTR-6-T Maximum Ratings & Electrical Characteristics
| Part Number | UDN2987LWTR-6-T |
| Manufacturer | Allegro MicroSystems |
| Function | 8-Channel Source Driver with Over-Current Protection |
| Topology | High-Side (Source) Bipolar Darlington Array |
| Number of Outputs | 8 |
| Output Current (per channel, continuous) | 350 mA |
| Load Supply Voltage | 5 V to 35 V |
| Logic Supply Voltage (VCC) | 5 V |
| Input Compatibility | 5 V and 12 V TTL, CMOS, DTL, PMOS, Schottky TTL |
| Input Threshold | Active-high (output ON when input HIGH) |
| Over-Current Protection | Yes, per channel |
| Output Clamp Diodes | Yes, for inductive loads |
| Package | 20-lead SOIC-W (wide-body, 7.5 mm body width) |
| Mounting Type | Surface Mount |
| Lead Finish | 100% matte-tin leadframe plating (lead-free, Pb-free) |
| RoHS Status | Compliant |
UDN2987LWTR-6-T Pin Configuration
| Pin 1 | IN1 — Logic input 1 (active high) - controls OUT1 |
| Pin 2 | IN2 — Logic input 2 (active high) - controls OUT2 |
| Pin 3 | IN3 — Logic input 3 (active high) - controls OUT3 |
| Pin 4 | IN4 — Logic input 4 (active high) - controls OUT4 |
| Pin 5 | IN5 — Logic input 5 (active high) - controls OUT5 |
| Pin 6 | IN6 — Logic input 6 (active high) - controls OUT6 |
| Pin 7 | IN7 — Logic input 7 (active high) - controls OUT7 |
| Pin 8 | IN8 — Logic input 8 (active high) - controls OUT8 |
| Pin 9 | GND — Logic ground reference |
| Pin 10 | VCC — 5 V logic supply for input interface |
| Pin 11 | VS — 5 V-35 V load supply |
| Pin 12 | COM — Clamp diode common return / inductive kickback node |
| Pin 13 | OUT8 — Sourcing output 8 |
| Pin 14 | OUT7 — Sourcing output 7 |
| Pin 15 | OUT6 — Sourcing output 6 |
| Pin 16 | OUT5 — Sourcing output 5 |
| Pin 17 | OUT4 — Sourcing output 4 |
| Pin 18 | OUT3 — Sourcing output 3 |
| Pin 19 | OUT2 — Sourcing output 2 |
| Pin 20 | OUT1 — Sourcing output 1 |
Typical Applications
UDN2987LWTR-6-T is suitable for 6 applications: Multi-Channel Relay Driver Board, Solenoid and Valve Array Driver, LED Display and Indicator Array Driver, Unipolar Stepper Motor Winding Driver, Thermal Printer Head Driver, Industrial 24 V Bus Sensor Array.
Multi-Channel Relay Driver Board
The UDN2987LWTR-6-T is purpose-built for driving arrays of relays in industrial control boards because each of its 8 sourcing outputs can directly switch the coil of a 5 V-24 V relay. With 350 mA per-channel current capability, the part comfortably drives standard signal relays (typically 70-150 mA coil current), and its active-high TTL/CMOS-compatible inputs make it a clean buffer for microcontroller or PLC GPIO pins. The integrated over-current protection on every channel protects against coil short faults and wiring mistakes, and the on-chip clamp diodes absorb the back-EMF when the relay coil is de-energised. A typical 8-relay board uses one UDN2987LWTR-6-T per bank of eight coils, with status LEDs wired in parallel to the outputs for visual feedback. The 20-SOIC-W footprint keeps the board compact while the wide body provides the thermal margin needed when multiple relays switch simultaneously.
Recommended
Solenoid and Valve Array Driver
In fluid-control systems and solenoid valve banks, the UDN2987LWTR-6-T provides 8 independent high-side switches capable of energising pneumatic or hydraulic solenoid coils from a 24 V industrial bus. The 5 V-35 V load supply range matches the common 24 V factory power rail directly, eliminating the need for an intermediate DC-DC converter. Each 350 mA channel covers small-to-medium proportional valves, while the per-channel over-current protection prevents damage from stuck valves or wiring faults that would otherwise destroy a discrete driver transistor. The integrated flyback clamp diodes are essential for solenoids, since the inductive kick at turn-off can otherwise exceed the output transistor Vbr and create EMI on the supply rail. Engineers typically combine the UDN2987LWTR-6-T with a CAN-controlled MCU such as STM32 to build a smart valve manifold.
Recommended
LED Display and Indicator Array Driver
The UDN2987LWTR-6-T drives 7-segment displays, dot-matrix LED panels, and indicator arrays directly because its 8 sourcing outputs can each supply up to 350 mA from a 5 V-35 V rail. For a 7-segment display, each segment is driven by one channel with the appropriate series resistor, and 8 channels are enough to drive one digit plus the decimal point. For a bar-graph or LED status panel, the wide supply range allows the part to feed high-brightness LEDs from a 12 V or even 24 V rail, reducing the per-LED current and improving efficiency. The integrated clamp diodes are useful when driving LED matrices that include multiplexed rows, since parasitic inductance in the wiring can otherwise cause voltage transients at turn-off. Active-high logic inputs make the driver a drop-in replacement for transistor arrays in legacy LED display designs.
Recommended
Unipolar Stepper Motor Winding Driver
Although dedicated stepper driver ICs are usually preferred, the UDN2987LWTR-6-T can source the four winding phases of small unipolar stepper motors from a 12 V-24 V supply. Each phase current is well below the 350 mA per-channel limit of the part for small (28 mm and 35 mm frame) steppers, and the on-chip over-current protection prevents winding shorts from damaging the IC. The active-high inputs accept step and direction pulses directly from a microcontroller GPIO, and the clamp diodes safely dissipate the inductive energy when each phase is commutated. By combining one UDN2987LWTR-6-T with a complementary ULN2803, designers can also build small bipolar half-bridges to drive bipolar steppers. This topology is common in legacy printer, scanner, and instrument designs where the UDN2987 has been used for decades.
Recommended
Thermal Printer Head Driver
Thermal printer heads require high-side switches capable of sourcing several hundred milliamps to each dot heating element, and the UDN2987LWTR-6-T fits this role in low-to-medium resolution thermal print heads (8-dot banks per IC). Each 350 mA channel directly switches the print-head element from a 5 V-24 V supply, and the integrated over-current protection prevents burnt elements from causing catastrophic IC failure. The active-high inputs latch from a print-controller ASIC or FPGA, and the small 20-SOIC-W footprint allows multiple drivers to be tiled along the length of the print head. While modern thermal heads use custom ASICs, the UDN2987LWTR-6-T remains a popular choice for legacy label printers, receipt printers, and DIY thermal printer projects where 8 dots per IC matches the print-head segment width.
Recommended
Industrial 24 V Bus Sensor Array
The UDN2987LWTR-6-T can switch 24 V sensors, photoelectric switches, and indicator lamps directly from a 24 V industrial bus, with each of the 8 channels sourcing up to 350 mA from the 24 V rail. Its 35 V absolute maximum supply voltage comfortably tolerates the 24 V +/-20% industrial tolerance, and the per-channel over-current protection is invaluable when a sensor wiring fault causes a short to ground. The 5 V CMOS-compatible inputs allow a 3.3 V or 5 V MCU to control 24 V loads safely through the IC, providing galvanic isolation of the logic return (5 V GND) from the load return (24 V GND) when the two grounds are kept separate. Typical applications include conveyor sortation, photo-eye arrays, stack-light indicators, and machine-tool annunciators on the factory floor.
Recommended
Recommended Products Summary
Engineering reference data for UDN2987LWTR-6-T — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | UDN2987LW-6-T | UDN2987A-6-T | TD62083AFG(O,EL) | TD62083APG | NJM2682V-TE1 |
|---|---|---|---|---|---|---|
| Brand | Allegro MicroSystems | Allegro MicroSystems | Allegro MicroSystems | Toshiba | Toshiba | NJR |
| Package | 20-SOIC-W | 20-SOIC-W | 20-DIP | 20-SOIC-W (SOP-20W) | 20-DIP | 20-SSOP |
| Output Channels | 8 | 8 | 8 | 8 | 8 | 8 |
| Output Current per Channel | 350 mA | 350 mA | 350 mA | 350 mA | 350 mA | 350 mA |
| Load Supply Voltage | 5 V to 35 V | 5 V to 35 V | 5 V to 35 V | 5 V to 35 V | 5 V to 35 V | 5 V to 35 V |
| Logic Compatibility | 5 V / 12 V TTL, CMOS, DTL, PMOS | 5 V / 12 V TTL, CMOS | 5 V / 12 V TTL, CMOS | 5 V CMOS / TTL | 5 V CMOS / TTL | CMOS / TTL |
Key Differentiators
- Integrated per-channel over-current protection (vs Toshiba TD62083AFG)
- Wide 5 V-35 V load supply range with 5 V CMOS/TTL/PMOS inputs (vs NJR NJM2682V-TE1)
- DABIC-5 monolithic bipolar-plus-CMOS die with on-chip clamp diodes (vs Discrete Darlington + diode designs)
Design Notes
Estimated: The 20-SOIC-W package has a typical theta-JA around 60-70 C/W on a 1-oz 2-layer board. At VS=24 V, VLOAD=5 V (relay coil), and IOUT=350 mA per channel, each channel dissipates roughly 6.65 W and the package dissipates up to ~50 W if all 8 channels are active - well beyond the SOIC-W rating. Designers must either limit the number of simultaneously-ON channels, drop VS to 12 V, or use copper pours / external heatsinks. Always verify package dissipation against the SOIC-W derating curve in the Allegro datasheet for the actual PCB layout.
Do not forget the COM pin (pin 12) - it is the common return for the integrated clamp diodes and must be tied to VS (pin 11) for inductive loads. If COM is left floating, the clamp diodes cannot return flyback current and the output transistors can avalanche, producing both EMI and reliability concerns. Also, unused input pins should be tied to GND (not left floating) to prevent false triggering from PCB leakage currents; the datasheet specifies this explicitly. Finally, observe input-edge timing if you parallel multiple channels - the OCP comparator shares internal bias and may interact if you switch channels in rapid succession.
Place a 0.1 uF ceramic decoupling capacitor as close as possible to the VCC pin (pin 10) and a bulk capacitor on the VS pin (pin 11) to handle the inrush current when multiple channels switch simultaneously. Wide copper pours on VS and GND reduce voltage transients and improve thermal dissipation; for high-current applications, use a copper pour on the top and inner layers under the SOIC-W pad. The COM pin trace should be a separate wide trace back to VS, not shared with the GND return, so that the clamp-diode return current does not flow through the input-side ground reference.
Compliance Information
100% matte-tin leadframe plating, lead-free and RoHS compliant per Allegro UDN2987 datasheet. Not AEC-Q100 qualified - this is an industrial / commercial-grade part. Halogen-free status inferred from Allegro's standard product compliance for SOIC-W packages - confirm with the manufacturer datasheet if required for certification.
