Texas Instruments SN10KHT5543NT

Overview

SN10KHT5543NT 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 bidirectional translation, 3.3 ns typical propagation delay (t_PLH/t_PHL), ±25 mA ECL output drive capability, and operates over 0°C to +70°C ambient temperature. It is used in mixed-logic digital test equipment interfacing TTL controllers with ECL-based timing generators.

For engineers reviewing the SN10KHT5543NT datasheet, SN10KHT5543NT pinout, SN10KHT5543NT application, or SN10KHT5543NT equivalent, key selection criteria include TTL input compatibility (V_IL = 0.8 V max, V_IH = 2.0 V min), ECL output swing (–1.49 V to –0.92 V), enable-controlled three-state outputs, and SOIC-24 package thermal and layout constraints.

Technical Context

This device implements TTL-compatible input stages driving differential ECL output pairs with complementary enable control. Each channel includes a TTL input buffer followed by a current-mode logic (CML) output stage with active pull-down and emitter-follower output configuration.

The SN10KHT5543NT uses open-emitter ECL outputs requiring external termination resistors to –2.0 V or –5.2 V supply rails. Its output enable (OE) pin controls all eight channels simultaneously, placing outputs in high-impedance state when asserted low, enabling bus-sharing in multi-translator systems.

Key Specifications

Pinout & Package

SN10KHT5543NT is packaged in a 24-pin SOIC (DW) body with 300-mil width, JEDEC MS-013AC compliant, RoHS-compliant green finish, and moisture sensitivity level (MSL) 1 (unlimited floor life at ≤30°C/60% RH).

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN10KHT5542NT and MC100ELT20DG, the SN10KHT5543NT uniquely provides native TTL input thresholds with active-low OE in a drop-in SOIC-24 footprint-enabling direct replacement of legacy designs without logic inversion or external components.

Availability

SN10KHT5543NT is available at Aetrix Electronics and suitable for digital test equipment interface, high-speed logic analyzer front-end, and mixed-logic bus arbitration requiring stable component supply and long-term obsolescence management.

Supply support for SN10KHT5543NT 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 devices with broad industrial, automotive, and communications product portfolios.

The SN10KHT5543NT belongs to TI's legacy bipolar logic family targeting high-speed digital test and measurement systems, engineered specifically for seamless interoperability between TTL control logic and ECL timing subsystems.

FAQ

What is the function of the OE pin on the SN10KHT5543NT?

The OE (Output Enable) pin on the SN10KHT5543NT is an active-low control that places all eight ECL outputs in high-impedance state when asserted low. When OE is high, outputs are enabled and drive their respective logic states. This allows bus sharing in multi-translator configurations and prevents signal contention on shared ECL lines. The SN10KHT5543NT requires OE to be pulled high via a resistor or driven actively to enable translation functionality.

Does the SN10KHT5543NT support both positive and negative ECL supply configurations?

The SN10KHT5543NT is specified for use with V_EE = –5.2 V and V_CC = +5.0 V only. It does not support positive ECL (PECL) configurations or V_EE = 0 V operation. Its internal biasing and output stage are optimized for standard negative ECL rails, and operation outside these voltages risks incorrect logic thresholds or damage. Always terminate ECL outputs to –2.0 V or –5.2 V using 50 Ω resistors as defined in the SN10KHT5543NT datasheet SDZS001A.

Can the SN10KHT5543NT be used with modern 3.3-V TTL logic?

The SN10KHT5543NT accepts standard TTL input thresholds (V_IL ≤ 0.8 V, V_IH ≥ 2.0 V) but is not guaranteed to interface reliably with 3.3-V TTL outputs due to insufficient noise margin and potential VIH violation. Its inputs expect 5-V TTL swing; connecting 3.3-V logic may result in marginal or undefined switching behavior. For 3.3-V systems, consider level-shifting or selecting a newer translator like SN65LVDS31, unless the 3.3-V source meets SN10KHT5543NT's 2.0-V minimum VIH under worst-case conditions.

What is the recommended termination scheme for SN10KHT5543NT ECL outputs?

Each ECL output of the SN10KHT5543NT must be terminated to either –2.0 V or –5.2 V using a 50 Ω resistor to maintain signal integrity and ensure proper voltage swing (–1.49 V to –0.92 V). The choice depends on system rail availability: –2.0 V termination yields lower power and reduced ground bounce, while –5.2 V matches legacy ECL standards. Unused outputs must still be terminated; floating ECL outputs cause instability and increased power consumption in the SN10KHT5543NT.

Is the SN10KHT5543NT pin-compatible with the SN10KHT5542NT?

Yes, the SN10KHT5543NT is pin-compatible with the SN10KHT5542NT in SOIC-24 (DW) package, sharing identical pin assignments and electrical characteristics except for OE polarity: SN10KHT5543NT uses active-low OE, while SN10KHT5542NT uses active-high OE. No PCB changes are required for physical replacement, but OE signal logic must be inverted to maintain functional equivalence in the SN10KHT5543NT.