Texas Instruments SN7445NSRE4

Overview

SN7445NSRE4 from Texas Instruments is a 4-bit binary-to-decimal decoder/driver IC in a 16-pin PDIP package, designed for direct interface with common-anode 7-segment LED displays. It features active-low outputs, TTL-compatible inputs, and operates over 0°C to 70°C. Its open-collector outputs support up to 80 mA per segment, enabling direct LED drive without external transistors in low-density displays.

For engineers reviewing the SN7445NSRE4 datasheet, SN7445NSRE4 pinout, SN7445NSRE4 application, or SN7445NSRE4 equivalent, key selection considerations include its active-low BCD-to-decimal decoding logic, open-collector output architecture, common-anode LED compatibility, temperature range compliance, and RoHS-compliant NIPDAU lead finish.

Technical Context

The SN7445NSRE4 implements a fixed BCD-to-decimal decoding function with four address inputs (A0–A3) and ten active-low decoded outputs (Y0–Y9). It uses standard TTL input thresholds and does not include latching, enable control, or internal current limiting.

All outputs are open-collector, requiring external pull-up resistors or direct connection to common-anode LED anodes. The device lacks built-in blanking, ripple blanking, or lamp-test functionality - those functions must be implemented externally if required.

Key Specifications

Pinout & Package

SN7445NSRE4 is housed in a 16-pin plastic dual in-line package (PDIP-N), 0.3-inch width, with standard DIP pin spacing (0.1 inch). Pin 1 is located at the left end of the top row when viewed from the top with notch or dot oriented left.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar BCD-to-decimal decoder/driver applications.

Compared with SN74LS45N and 74HC4511PW, the SN7445NSRE4 offers higher output drive strength and simpler interface for static common-anode displays, but lacks latching and diagnostic features - making it optimal for cost-driven, non-multiplexed indicator applications.

Availability

SN7445NSRE4 is available at Aetrix Electronics and suitable for industrial panel meters, legacy test equipment displays, and appliance control panels requiring stable component supply and long-term obsolescence management.

Supply support for SN7445NSRE4 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 company headquartered in Dallas, Texas, delivering analog and embedded processing solutions across industrial, automotive, and personal electronics markets.

The SN7445NSRE4 belongs to TI's legacy 74xx TTL logic family, engineered specifically for reliable, low-cost digital display interfacing in commercial-grade equipment where deterministic decoding and robust output drive are essential.

FAQ

What is the maximum output sink current per pin on the SN7445NSRE4?

The SN7445NSRE4 supports up to 80 mA DC sink current per output pin (Y0–Y9) when VCC = 5 V and ambient temperature is ≤25°C. Derating applies above 25°C; at 70°C, maximum recommended sink current is 60 mA per output to maintain reliability and avoid thermal shutdown.

Does the SN7445NSRE4 include an internal latch or memory function?

No, the SN7445NSRE4 is a combinational logic device with no internal latch or storage capability. Output states change asynchronously with input BCD changes. External latching (e.g., using 74LS373) is required if stable display during input transitions is needed.

Can the SN7445NSRE4 drive common-cathode LED displays?

No, the SN7445NSRE4 has active-low open-collector outputs designed exclusively for common-anode displays. To drive common-cathode displays, a logic inverter stage or complementary driver IC such as the SN7446 (which features active-low outputs with built-in current limiting) is required.

What is the purpose of the open-collector outputs on the SN7445NSRE4?

The open-collector outputs on the SN7445NSRE4 allow flexible pull-up voltage selection (e.g., 5 V, 12 V, or higher), enable wired-OR logic for shared bus signaling, and simplify interface with diverse display technologies including incandescent lamps and high-voltage LEDs - all while maintaining TTL input compatibility.

Is the SN7445NSRE4 RoHS compliant and what is its lead finish?

Yes, the SN7445NSRE4 is RoHS compliant with a NIPDAU (nickel/palladium/gold) lead finish. This surface finish ensures solderability, corrosion resistance, and compatibility with standard Pb-free reflow profiles, meeting IPC-J-STD-020 moisture sensitivity requirements.