Texas Instruments SN74LS247NE4

Overview

SN74LS247NE4 from Texas Instruments is a 7-segment BCD-to-7-segment decoder/driver IC with active-low open-collector outputs, designed for direct interface to common-anode LED displays. It features TTL-compatible inputs, lamp test (LT̅), ripple blanking input (RBI̅), and blanking input (BI̅/RBO̅), operating across 0°C to 70°C with V_CC = 4.75–5.25 V and I_OH = –150 mA per segment.

For engineers reviewing the SN74LS247NE4 datasheet, SN74LS247NE4 pinout, SN74LS247NE4 application, or SN74LS247NE4 equivalent, key selection considerations include its active-low output architecture, common-anode LED drive capability, built-in blanking and test controls, and PDIP-16 packaging for through-hole prototyping and legacy industrial panel designs.

Technical Context

The SN74LS247NE4 implements combinational logic decoding of 4-bit binary-coded decimal (BCD) inputs (A0–A3) into seven active-low outputs (a–g) that sink current to illuminate segments of a common-anode display. Its internal logic includes priority encoding for blanking functions: BI̅/RBO̅ serves as both blanking input and ripple blanking output, while RBI̅ enables zero-suppression cascading in multi-digit displays.

Unlike standard 74LS248 (common-cathode), the SN74LS247NE4 uses open-collector outputs requiring external pull-up resistors and is not compatible with TTL-to-TTL direct driving without current-limiting design. Its propagation delay (t_PLH/t_PHL) is typically 30 ns at V_CC = 5 V and T_A = 25°C, and it draws I_CC ≈ 30 mA max under full segment drive conditions.

Key Specifications

Pinout & Package

SN74LS247NE4 is housed in a 16-pin plastic dual in-line package (PDIP-N), with 0.3-inch body width, 0.1-inch lead pitch, and through-hole mounting. The package conforms to JEDEC MS-001 and supports wave soldering and manual assembly.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar BCD-to-7-segment decoder applications.

Compared with SN74LS247NE4, SN74LS248N requires display polarity reversal and output rewiring, while 74HC4511PW offers enhanced features at the cost of layout and interface redesign - making SN74LS247NE4 the optimal choice for maintaining legacy common-anode TTL systems.

Availability

SN74LS247NE4 is available at Aetrix Electronics and suitable for digital panel meters, industrial counter displays, and test equipment readouts requiring stable component supply and long-term obsolescence resilience.

Supply support for SN74LS247NE4 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 U.S.-based semiconductor company founded in 1930, specializing in analog, embedded processing, and logic ICs with global manufacturing and distribution infrastructure.

The SN74LS247NE4 belongs to TI's legacy 74LS logic family, engineered specifically for reliable, low-cost BCD decoding and LED driving in commercial-grade instrumentation and industrial control panels.

FAQ

What is the primary function of the SN74LS247NE4?

The SN74LS247NE4 is a BCD-to-7-segment decoder/driver IC with active-low open-collector outputs optimized for common-anode LED displays. It converts 4-bit binary-coded decimal inputs into seven segment drive signals (a–g), and includes lamp test (LT̅), blanking (BI̅/RBO̅), and ripple blanking (RBI̅) controls. Its logic and timing are fully compliant with the 74LS family specification, and it operates within 0°C to +70°C.

Can SN74LS247NE4 directly drive common-cathode LED displays?

No, SN74LS247NE4 cannot directly drive common-cathode LED displays. Its outputs are active-low open-collector, designed to sink current into the anodes of common-anode LEDs. Driving a common-cathode display would require external inverters or level-shifting circuitry - and even then, timing and drive strength would deviate from spec. For common-cathode applications, SN74LS248N or 74HC4511 are appropriate alternatives.

What is the purpose of the BI̅/RBO̅ pin on SN74LS247NE4?

The BI̅/RBO̅ pin on SN74LS247NE4 serves dual roles: as a blanking input (BI̅) to force all segment outputs high (blanking the display), and as a ripple blanking output (RBO̅) that goes low only when all inputs are 0000 *and* RBI̅ is low and LT̅ is high. This enables cascaded zero suppression across multiple digits - for example, suppressing leading zeros in a 4-digit counter - without external logic.

Does SN74LS247NE4 require external pull-up resistors on its outputs?

Yes, SN74LS247NE4 requires external pull-up resistors on all segment outputs (pins 9–15) because they are open-collector. These resistors set segment current and brightness; typical values range from 330 Ω to 1 kΩ depending on LED forward voltage and desired current (≤150 mA per output). No internal pull-ups exist - omitting them results in undefined or floating outputs.

Is SN74LS247NE4 RoHS compliant?

Yes, SN74LS247NE4 is RoHS compliant, as confirmed by Texas Instruments' official packaging documentation. It carries "Yes" in the RoHS column of TI's packaging addendum, uses NiPdAu (NIPDAU) lead finish, and meets EU Directive 2011/65/EU requirements for restricted substances. The PDIP package contains no lead exemptions and is suitable for environmentally regulated commercial electronics production.