Texas Instruments SN100KT5542DW

Overview

SN100KT5542DW from Texas Instruments is an octal TTL-to-ECL translator with output enable, designed for high-speed level translation between TTL logic families and ECL systems. It features 8-channel unidirectional translation, −5.2 V V_CC, 0 V V_EE, typical propagation delay of 2.5 ns, and operates over the full military temperature range (−55°C to +125°C) in a 24-pin SOIC package.

For engineers reviewing the SN100KT5542DW datasheet, SN100KT5542DW pinout, SN100KT5542DW application, or SN100KT5542DW equivalent, this device supports critical timing-critical interface bridging in legacy military/aerospace digital systems where TTL logic must drive ECL receivers with precise skew control and guaranteed output disable.

Technical Context

This translator implements active-low output enable (OE̅) to simultaneously gate all eight ECL outputs into high-impedance state, enabling bus sharing in multi-driver architectures. Its internal design uses emitter-follower output stages with matched delay paths to minimize inter-channel skew (<0.3 ns).

It requires dual supplies: −5.2 V on V_CC (ECL side) and 0 V on V_EE, with TTL inputs compatible with standard 5-V logic thresholds and ECL outputs delivering −1.3 V low / −0.9 V high levels into 50-Ω loads.

Key Specifications

Pinout & Package

SN100KT5542DW is housed in a 24-pin SOIC (DW) package with standard 0.300-inch body width and 1.27-mm pitch. Pin 1 is marked by a beveled corner or dot; leads are gull-wing, surface-mount compatible.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar TTL-to-ECL translation applications.

Compared with SN100KT5542DW, SN100K112DW removes output control at the cost of bus flexibility, while MC100ELT24DG offers faster speed and modern supply compatibility but demands PCB redesign and new termination schemes.

Availability

SN100KT5542DW is available at Aetrix Electronics and suitable for radar signal processing, avionics bus interfacing, and military data link systems requiring stable component supply despite its obsolete status.

Supply support for SN100KT5542DW 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 technologies for industrial, automotive, and defense markets.

The SN100K series was developed by Texas Instruments specifically for high-reliability military and aerospace applications requiring robust TTL-to-ECL translation with guaranteed timing and environmental performance.

FAQ

What is the function of the OE̅ pin on the SN100KT5542DW?

The OE̅ (Output Enable, active-low) pin on the SN100KT5542DW controls all eight ECL outputs simultaneously. When OE̅ is HIGH, all Y0–Y7 outputs enter high-impedance state, isolating the device from the ECL bus. When OE̅ is LOW, translation proceeds normally. This feature is essential for bus arbitration in multi-transmitter systems and is a defining capability of the SN100KT5542DW versus non-enabled variants like SN100K112DW.

Does the SN100KT5542DW support 3.3-V TTL inputs?

No, the SN100KT5542DW does not support 3.3-V TTL inputs. Its input stage is designed for standard 5-V TTL logic levels (0.8 V threshold for LOW, 2.0 V for HIGH) and is not compatible with LVTTL or LVCMOS signaling. Applying 3.3-V signals may result in marginal or incorrect switching behavior. For 3.3-V compatibility, consider alternatives such as MC100ELT24DG, which explicitly specifies 3.3-V TTL input thresholds.

What is the recommended termination for SN100KT5542DW ECL outputs?

The SN100KT5542DW ECL outputs require external 50-Ω pull-down resistors from each Y0–Y7 pin to V_EE (0 V) to establish proper ECL logic levels (−1.3 V for LOW, −0.9 V for HIGH) and match 50-Ω transmission lines. No internal termination is provided. Improper termination causes signal reflection, degraded noise margin, and timing violations-especially critical in the SN100KT5542DW's 2.5 ns propagation window.

Is the SN100KT5542DW RoHS compliant?

The SN100KT5542DW is not RoHS compliant. Per TI's packaging documentation, its eco-plan is listed as "TBD", and no Pb-Free or Green conversion was defined prior to obsolescence. The device contains leaded solder finish and was manufactured before RoHS enforcement timelines. For RoHS-compliant alternatives, consult TI's current ELT or ELE series translators with documented Pb-Free status.

Can the SN100KT5542DW operate with V_CC = −4.5 V instead of −5.2 V?

No, the SN100KT5542DW must use −5.2 V on V_CC. Its internal bias networks, output voltage levels, and AC specifications (including 2.5 ns propagation delay and 0.3 ns skew) are characterized and guaranteed only at −5.2 V. Operation at −4.5 V may cause output level shift, increased delay, reduced noise margin, and potential failure to meet MIL-STD-883 requirements-invalidating the SN100KT5542DW's qualified performance envelope.