Texas Instruments ULN2003BPWR

Overview

ULN2003BPWR from Texas Instruments is a 7-channel high-voltage, high-current Darlington transistor array designed for logic-level interfacing to inductive and resistive loads. It delivers 500 mA per channel, supports up to 50 V output voltage, integrates input base resistors (2.7 kΩ) and common-cathode clamp diodes, and operates across –40°C to +105°C - widely used in relay driver circuits for industrial control panels.

For engineers reviewing the ULN2003BPWR datasheet, ULN2003BPWR pinout, ULN2003BPWR application, or ULN2003BPWR equivalent, key selection criteria include per-channel sink current capability, integrated flyback diode configuration, thermal derating at elevated ambient temperatures, and compatibility with 3.3 V/5 V TTL/CMOS logic inputs without external biasing.

Technical Context

The ULN2003BPWR implements seven independent NPN Darlington pairs, each with a dedicated 2.7-kΩ series input resistor enabling direct connection to standard logic families. Its open-collector outputs share a common emitter (E) and a common cathode node (COM) for internal clamp diodes - essential for suppressing inductive kickback during relay or solenoid turn-off.

Each Darlington stage provides high DC current gain (h_FE > 1000 at I_C = 100 mA), low saturation voltage (V_CE(sat) ≤ 1.3 V at I_C = 200 mA), and robust ESD protection (2000 V HBM). The device operates with no external power supply beyond the COM rail and load supply, relying solely on logic-level inputs and load-side voltage sourcing.

Key Specifications

Pinout & Package

TSSOP-16 package (5.00 mm × 4.40 mm), 1.2 mm max height, lead-free, RoHS-compliant, moisture sensitivity level (MSL) 1 - suitable for fine-pitch automated assembly and reflow soldering.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar Darlington array applications.

Compared with ULN2003AD and STPIC6C595, the ULN2003BPWR uniquely balances compact TSSOP packaging, integrated flyback protection, and 500 mA per-channel sink capability - making it the optimal choice for space-constrained, inductive-load-dominant industrial interfaces requiring zero external protection components.

Availability

ULN2003BPWR is available at Aetrix Electronics and suitable for industrial automation, printer subsystems, and automotive body electronics requiring stable component supply, long-lifecycle support, and RoHS-compliant manufacturing.

Supply support for ULN2003BPWR 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

Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and connectivity technologies - serving industrial, automotive, and communications markets with high-reliability silicon solutions.

The ULN2003BPWR belongs to TI's legacy high-voltage interface portfolio, engineered specifically for robust logic-to-load bridging in harsh environments where ESD resilience, thermal stability, and functional simplicity are prioritized over digital intelligence.

FAQ

What is the maximum continuous current per channel for ULN2003BPWR?

The ULN2003BPWR is rated for 500 mA DC collector current per channel under recommended operating conditions. This rating assumes proper thermal management - at 25°C ambient, full 7-channel operation is feasible; at 70°C ambient, derating to ~300 mA per channel is advised based on TSSOP thermal resistance (R_θJA = 105.5°C/W) and maximum junction temperature of 125°C. Always verify power dissipation using V_CE(sat) and actual load current in your design.

Can ULN2003BPWR drive inductive loads without external diodes?

Yes, ULN2003BPWR can drive inductive loads without external flyback diodes - provided the COM pin is connected to the positive side of the inductive load supply. The device integrates seven common-cathode clamp diodes between each output (1C–7C) and COM, which conduct the back-EMF current during turn-off. If COM is left floating or grounded, external diodes must be added to prevent damage.

Is ULN2003BPWR compatible with 3.3 V microcontroller GPIOs?

Yes, ULN2003BPWR is fully compatible with 3.3 V logic inputs. Its 2.7-kΩ internal base resistors ensure sufficient drive current (≥1.2 mA at 3.3 V) to saturate each Darlington pair, achieving V_CE(sat) ≤ 1.3 V at 200 mA load. No level-shifting or external resistors are required - verified across –40°C to +105°C operating range per datasheet Section 6.5 and 6.6.

What is the purpose of the E pin on ULN2003BPWR?

Pin E (Emitter) is the common emitter connection for all seven Darlington transistors. It serves as the return path for all sink currents and must be connected to the system ground or low-side reference. Total current through E can reach 2.5 A when all channels operate at 500 mA - therefore, PCB trace width and grounding strategy must accommodate this aggregate current to avoid voltage drop or heating.

How does ULN2003BPWR differ from ULN2003A in practical use?

The ULN2003BPWR offers a >4× reduction in output leakage current (I_CEX ≤ 20 μA vs. ULN2003A's ~100 μA) and improved thermal specifications - particularly relevant in battery-powered or high-impedance sensing applications where leakage could cause false triggering or excessive standby drain. All other electrical parameters, pinout, and functionality remain identical, ensuring drop-in replacement capability in existing designs.