Texas Instruments SN7445NE4

Overview

SN7445NE4 from Texas Instruments is a 16-pin BCD-to-decimal decoder/driver IC in PDIP package, operating from 4.75 V to 5.25 V, with TTL-compatible inputs and open-collector outputs capable of sinking up to 80 mA per output, used for driving common-anode 7-segment displays and decimal indicator lamps in industrial control panels.

For engineers reviewing the SN7445NE4 datasheet, SN7445NE4 pinout, SN7445NE4 application, or SN7445NE4 equivalent, key selection considerations include its open-collector output drive strength, BCD input decoding logic, temperature range (0°C to 70°C), RoHS-compliant NIPDAU lead finish, and compatibility with legacy TTL-level systems requiring direct lamp or LED segment drive without external current-limiting resistors on the anode side.

Technical Context

The SN7445NE4 implements active-low BCD-to-decimal decoding with four address inputs (A0–A3) and ten active-low decoded outputs (Y0–Y9), where each output asserts low when its corresponding BCD value (0–9) is present. It uses standard bipolar TTL circuitry with Schottky-clamped transistors for improved switching speed and noise immunity.

Its open-collector outputs require external pull-up to V_CC or higher voltage (up to 15 V), enabling direct interface to lamps, relays, or optocouplers. Input thresholds are defined at V_IL = 0.8 V max and V_IH = 2.0 V min, ensuring robust noise margin in mixed-signal industrial environments.

Key Specifications

Pinout & Package

SN7445NE4 is housed in a 16-pin plastic dual in-line package (PDIP-N), 0.300-inch wide body, with standard through-hole mounting and 0.100-inch pin pitch. Pin 1 is located at the top-left corner adjacent to the notch or dot marking.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN7445N, SN7445NE4 offers identical functionality with enhanced traceability; compared with 74HC4511, it provides direct TTL-compatible drive and open-collector flexibility but lacks CMOS power efficiency and auxiliary control pins.

Availability

SN7445NE4 is available at Aetrix Electronics and suitable for industrial panel meters, legacy test equipment refurbishment, and programmable logic controller (PLC) I/O modules requiring stable component supply and long-term manufacturability assurance.

Supply support for SN7445NE4 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, embedded processing, and logic products for industrial, automotive, and communications markets since 1930.

The SN7445NE4 belongs to TI's classic 74xx TTL logic family, designed specifically for robust, high-current digital interface tasks in non-portable, mains-powered equipment where reliability and direct load drive are prioritized over power efficiency.

FAQ

What is the maximum output sink current rating for SN7445NE4?

The SN7445NE4 is rated for 80 mA DC sink current per output (Y0–Y9) under specified conditions (T_A = 25°C, V_CC = 5 V). This rating enables direct drive of incandescent lamps and high-brightness LEDs without external buffers. Derating applies above 25°C ambient; consult the Absolute Maximum Ratings table in the official SN7445 datasheet for thermal limits. SN7445NE4 maintains this performance across its full 0°C to 70°C operating range.

Is SN7445NE4 pin-compatible with older SN7445 variants like SN7445N?

Yes, SN7445NE4 is fully pin-compatible and functionally identical to SN7445N - both use the same PDIP-16 package, identical pinout, and match all DC and AC electrical specifications. The "E4" suffix denotes TI's enhanced manufacturing flow with tighter process controls and extended traceability, but no changes to footprint, timing, or logic behavior. SN7445NE4 can replace SN7445N in existing designs without modification.

Does SN7445NE4 support driving common-anode 7-segment displays?

SN7445NE4 does not natively drive 7-segment displays - it is a BCD-to-decimal decoder with ten active-low outputs (Y0–Y9), intended for one-of-ten decimal indication (e.g., lamps labeled 0–9). For 7-segment displays, a dedicated 7-segment decoder like SN7447 is required. SN7445NE4 outputs can drive individual segments only if externally wired as discrete signals, but no internal segment mapping is provided.

What is the input voltage threshold range for SN7445NE4?

SN7445NE4 uses standard TTL input thresholds: V_IL (input low voltage) is guaranteed ≤ 0.8 V, and V_IH (input high voltage) is guaranteed ≥ 2.0 V, with typical values of 0.4 V and 2.4 V respectively. These thresholds ensure compatibility with 74LS, 74S, and other TTL-family outputs. Inputs tolerate noise margins of at least 0.4 V low and 0.4 V high under nominal conditions. SN7445NE4 maintains these thresholds across its full 0°C to 70°C operating range.

Can SN7445NE4 operate with a 3.3 V supply?

No, SN7445NE4 is a bipolar TTL device designed for 5 V ±5% operation (4.75 V to 5.25 V). It will not function reliably at 3.3 V: input thresholds become undefined, propagation delays increase significantly, and output drive capability collapses. For 3.3 V systems, consider CMOS alternatives such as 74LVC138 or 74LVX138 with appropriate level translation. SN7445NE4 requires strict adherence to its specified 5 V supply range.