Texas Instruments SN65ELT22DGK

Overview

SN65ELT22DGK from Texas Instruments is a dual TTL-to-differential PECL translator in VSSOP-8 package, operating from 4.2 V to 5.7 V supply, delivering ≤1.1 ns max propagation delay, <50 ps typ output-to-output skew, and 470–500 MHz max switching frequency across –40°C to +85°C. It enables high-speed clock/data transmission over backplanes with built-in temperature compensation.

For engineers reviewing the SN65ELT22DGK datasheet, SN65ELT22DGK pinout, SN65ELT22DGK application, or SN65ELT22DGK equivalent, key selection criteria include TTL input compatibility, PECL differential output drive capability, low inter-output skew, thermal performance in VSSOP packaging, and drop-in compatibility with MC10ELT22/MC100ELT22 in signal integrity-critical timing paths.

Technical Context

The SN65ELT22DGK implements two independent TTL-to-PECL translation channels, each with complementary PECL outputs (Qx/Qx) driven by single-ended TTL inputs (D0/D1). Its internal circuitry maintains stable DC output levels-VOH = 3915–4120 mV and VOL = 3170–3380 mV-when terminated into 50 Ω to VCC – 2.0 V.

AC performance is defined across temperature and supply voltage: propagation delay (tPLH/tPHL) remains ≤1.1 ns at 85°C and 4.2 V, while device-to-device skew stays ≤100 ps under matched VCC conditions. Random clock jitter is specified at 0.5 ps RMS, supporting precise timing alignment in multi-channel systems.

Key Specifications

Pinout & Package

VSSOP-8 (DGK) package: 3.0 mm × 3.0 mm body, 1.1 mm max height, 0.65 mm lead pitch, exposed pad not present. RoHS-compliant NiPdAu lead finish, MSL Level-1 (260°C peak reflow).

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN65ELT22DGK, MC100ELT22DT offers identical AC/DC behavior but demands more PCB area and dissipates heat less efficiently, while SN65ELT22D provides drop-in electrical equivalence with relaxed board-space constraints-making SN65ELT22DGK optimal for space-constrained, thermally demanding backplane nodes.

Availability

SN65ELT22DGK is available at Aetrix Electronics and suitable for backplane clock distribution, high-speed data link interfacing, test equipment timing modules, and industrial control synchronization requiring stable component supply across extended temperature ranges.

Supply support for SN65ELT22DGK 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, designing and manufacturing analog ICs, embedded processors, and connectivity solutions for industrial, automotive, and communications markets.

The SN65ELT22DGK belongs to TI's high-speed interface translator product line, engineered specifically for low-skew, low-jitter signal conversion between TTL and PECL domains in telecom infrastructure and precision instrumentation.

FAQ

What is the recommended termination for SN65ELT22DGK PECL outputs?

The SN65ELT22DGK PECL outputs require 50 Ω resistive termination to VCC – 2.0 V on both true and complement lines (e.g., Q0 and Q0). This configuration establishes the proper common-mode voltage (~1.3 V) and differential swing (~800 mVpp) per TI SLLS924 specification. Failure to terminate correctly results in undefined output levels and degraded timing margins. The SN65ELT22DGK datasheet Figure 1 shows this exact topology with dual 50 Ω resistors referenced to VCC – 2 V.

Does SN65ELT22DGK support operation below 4.2 V supply?

No, SN65ELT22DGK is not characterized or guaranteed for operation below 4.2 V. Absolute maximum ratings permit up to 6 V, but the recommended operating range is strictly 4.2 V to 5.7 V per the datasheet's "Operating Range" section. At 4.0 V, parameters like propagation delay, skew, and output voltage compliance fall outside published specifications, risking timing violations in production systems. The SN65ELT22DGK must be powered within its validated window to ensure <50 ps skew and ≤1.1 ns delay.

Can SN65ELT22DGK inputs be left floating during operation?

No, SN65ELT22DGK inputs must never be left floating. The datasheet explicitly states: "The output is undetermined when the inputs are left floating." Unconnected D0 or D1 pins cause unpredictable PECL output states, leading to metastability, excessive current draw, or system-level timing faults. Each TTL input requires a defined logic level-either pulled high via ≥10 kΩ to VCC or low to GND-to guarantee deterministic Qx/Qx behavior. This requirement applies equally to both channels of the SN65ELT22DGK.

Is SN65ELT22DGK pin-compatible with SN65ELT22D?

Yes, SN65ELT22DGK and SN65ELT22D share identical pin functions and numbering (D0, D1, Q0, Q0, GND, Q1, Q1, VCC), but differ in physical package: DGK is VSSOP-8 (3.0 × 3.0 mm), D is SOIC-8 (5.3 × 6.2 mm). Their pinouts match electrically and logically, enabling schematic reuse, though PCB layout must be redesigned for the smaller VSSOP footprint. Both variants carry the same SN65ELT22DGK marking and are drop-in replacements at the netlist level.

What is the thermal performance difference between SN65ELT22DGK and SN65ELT22D?

SN65ELT22DGK (VSSOP-8) has higher junction-to-ambient thermal resistance than SN65ELT22D (SOIC-8): 213 °C/W (Low-K board) vs. 79 °C/W. This means for identical power dissipation (≈100 mW), SN65ELT22DGK's die temperature rises ~135 °C more than SN65ELT22D under the same board conditions. Designers using SN65ELT22DGK must allocate additional copper area or airflow to maintain junction temperature below 125°C-especially critical in high-density backplane slots where SN65ELT22DGK is commonly deployed.