Texas Instruments SN74LS258BNSR

Overview

SN74LS258BNSR from Texas Instruments is a quadruple 2-line to 1-line data selector/multiplexer in a 16-pin SOP (NS) package, operating over 0°C to 70°C, with TTL-compatible inputs and outputs, 15 ns typical propagation delay, and 20 mA output drive capability. It enables digital signal routing in bus management and data path control applications.

For engineers reviewing the SN74LS258BNSR datasheet, SN74LS258BNSR pinout, SN74LS258BNSR application, or SN74LS258BNSR equivalent, this page delivers verified functional identity, confirmed pin mapping, real-world timing and drive specifications, and validated alternative options for legacy TTL system design and repair.

Technical Context

The SN74LS258BNSR implements four independent 2:1 multiplexers sharing a common select (S) and enable (G̅) control line. Each channel selects between two digital inputs (A or B) based on the logic state of S, with output disabled when G̅ is high.

It uses bipolar TTL circuitry with Schottky-clamped transistors to achieve improved speed and noise immunity versus standard 74-series logic. Input thresholds align with standard TTL voltage levels (V_IL ≤ 0.8 V, V_IH ≥ 2.0 V), and outputs drive standard TTL loads directly without pull-ups.

Key Specifications

Pinout & Package

SOP (NS) package: 16-pin small-outline plastic package, 10.4 mm × 5.3 mm body, 2.00 mm max height, gull-wing leads, pin 1 marked by beveled corner.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 2:1 multiplexer applications.

Compared with SN74LS257BN and SN74LS157DR, the SN74LS258BNSR delivers identical multiplexing logic in a RoHS-compliant, surface-mount SOP package optimized for automated production, while maintaining full compatibility with legacy 74LS timing and drive requirements.

Availability

SN74LS258BNSR is available at Aetrix Electronics and suitable for bus arbitration logic, data path switching, legacy system repair, and digital test fixture control requiring stable component supply and long-term obsolescence mitigation.

Supply support for SN74LS258BNSR 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 founded in 1930, specializing in analog, embedded processing, and logic solutions with broad industrial, automotive, and communications reach.

The SN74LS258BNSR belongs to TI's legacy 74LS logic family, designed specifically for reliable, low-cost digital signal routing in commercial-grade systems where TTL compatibility, predictable timing, and field-proven robustness are essential.

FAQ

What is the primary function of the SN74LS258BNSR?

The SN74LS258BNSR is a quadruple 2-line to 1-line data selector/multiplexer. It routes four independent pairs of digital inputs (A1/B1 through A4/B4) to corresponding outputs (Y1–Y4) based on a shared select (S) signal, with all channels enabled or disabled simultaneously via the active-low G̅ input. Its function is defined in the SDLS148 datasheet and matches the standard 74LS257/258 truth table.

Is the SN74LS258BNSR pin-compatible with the SN74LS257B series?

Yes, the SN74LS258BNSR is functionally and pin-compatible with the SN74LS257B family, including SN74LS257BN and SN74LS257BNSR. Both share identical pin assignments, logic behavior, DC specifications, and AC timing (15 ns t_pd). The "258" designation reflects TI's internal variant labeling but does not indicate functional divergence in this case.

What are the key timing parameters for SN74LS258BNSR in normal operation?

At V_CC = 5 V and T_A = 25°C, the SN74LS258BNSR exhibits t_pd = 15 ns maximum (A/B to Y), t_su = 20 ns minimum (S or G̅ setup before A/B transition), and t_h = 0 ns hold time. These values ensure reliable operation in synchronous 20–25 MHz control paths and are fully specified in the SDLS148 production data sheet.

Can SN74LS258BNSR drive standard TTL loads directly?

Yes, the SN74LS258BNSR provides ±20 mA output drive capability, meeting or exceeding standard TTL input current requirements (I_IL = –1.6 mA, I_IH = 40 µA). Each output can drive up to 10 standard TTL loads without external buffers, supporting fanout-critical applications like bus gating and signal distribution.

Does SN74LS258BNSR require external pull-up resistors on its outputs?

No, the SN74LS258BNSR features totem-pole (push-pull) outputs and does not require external pull-up resistors. Its outputs actively drive both logic high and low states, delivering V_OH ≥ 2.7 V and V_OL ≤ 0.5 V under rated load conditions - consistent with standard TTL interfacing requirements.