Texas Instruments SN65EPT21DGKR

Overview

SN65EPT21DGKR from Texas Instruments is a 3.3-V differential PECL/LVDS-to-TTL level translator in an 8-pin VSSOP package, featuring 1 ns propagation delay, >300 MHz maximum switching frequency, and 24-mA TTL output drive. It operates across –40°C to 85°C and supports backplane clock/data transmission with built-in input biasing for open-input stability.

For engineers reviewing the SN65EPT21DGKR datasheet, SN65EPT21DGKR pinout, SN65EPT21DGKR application, or SN65EPT21DGKR equivalent, this device is selected for high-speed signaling level conversion where precise timing, low jitter (≤5 ps RMS), and single-supply 3.3-V operation are required in space-constrained PCB layouts.

Technical Context

The SN65EPT21DGKR implements a differential input stage compatible with LVPECL, LVDS, and CML logic families, with internal 50-kΩ pull-up/pull-down resistors enabling stable operation when inputs are left floating. Its VBB reference output (1.91–2.16 V) provides bias for single-ended ac-coupled inputs.

It delivers rail-to-rail TTL-compatible outputs (VOH ≥ 2.4 V at –3 mA, VOL ≤ 0.5 V at 24 mA) with matched rise/fall times (250–900 ps) and tight duty-cycle skew (<250 ps). The device uses no external components for basic operation beyond a 0.01-μF decoupling capacitor between VCC and VBB when VBB is utilized.

Key Specifications

Pinout & Package

SN65EPT21DGKR is housed in an 8-pin VSSOP (DGK) package measuring 3.0 mm × 3.0 mm × 1.1 mm, with exposed thermal pad (EP) connected to GND for enhanced thermal performance. Pin 1 is located at the top-left corner adjacent to the index area per JEDEC MO-187.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar differential-to-single-ended level translation applications.

Compared with MC100EPT21DG and SN65LVDS31DR, the SN65EPT21DGKR uniquely combines 3.3-V operation, PECL/LVDS/CML input flexibility, and 24-mA TTL output in a space-saving VSSOP package-making it the sole option for compact, single-rail, mixed-standard level translation in industrial timing applications.

Availability

SN65EPT21DGKR is available at Aetrix Electronics and suitable for backplane clock distribution, optical module control, and high-speed data interface applications requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant packaging.

Supply support for SN65EPT21DGKR 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 delivering analog, embedded processing, and connectivity solutions with emphasis on reliability, precision, and power efficiency.

The SN65EPT21DGKR belongs to TI's high-speed interface translator product line, engineered specifically for robust signal integrity in industrial communications, test equipment, and optical networking systems operating at 300+ MHz.

FAQ

What is the recommended decoupling for SN65EPT21DGKR when using the VBB pin?

When utilizing the VBB pin on the SN65EPT21DGKR, place a 0.01-μF ceramic capacitor between VCC and VBB, placed as close as possible to the device. Ensure total sink/source current to VBB remains below ±0.5 mA. Do not connect VBB to any external voltage source or load exceeding this limit, as it may degrade reference accuracy or damage internal circuitry. Leaving VBB open is acceptable if unused.

Can SN65EPT21DGKR accept LVDS inputs while driving TTL outputs?

Yes, the SN65EPT21DGKR accepts LVDS inputs directly on its D/D pins and produces TTL-compatible outputs on Q. Its input stage is designed for LVPECL, LVDS, and CML logic families, and its output meets standard TTL voltage thresholds (VOH ≥ 2.4 V, VOL ≤ 0.5 V) with 24-mA drive capability. No external resistors or level-shifting components are needed for basic LVDS-to-TTL translation.

Is SN65EPT21DGKR pin-compatible with MC10EPT21 devices?

Yes, SN65EPT21DGKR is drop-in compatible with MC10EPT21 and MC100EPT21 per TI documentation. It shares identical pin assignments, functional behavior, and AC timing specifications. However, SN65EPT21DGKR operates at 3.3 V only, whereas MC10EPT21 requires 5 V - so PCB layout can be reused, but power supply must be adjusted accordingly.

What is the purpose of the NC pins on SN65EPT21DGKR?

Pins 3 and 8 of the SN65EPT21DGKR are designated NC (No Connect) and are not internally bonded. They must remain unconnected on the PCB to prevent unintended coupling, noise injection, or ESD discharge paths. TI specifies these pins as electrically isolated; routing traces or placing vias to them violates the validated layout guidance and may impact timing or EMI performance.

Does SN65EPT21DGKR support single-ended input operation?

Yes, SN65EPT21DGKR supports single-ended input operation. When used this way, tie the unused differential input to the VBB pin (1.91–2.16 V), which serves as a stable mid-supply reference. This configuration maintains proper input biasing and ensures valid logic interpretation. Do not leave either D or D pin floating - always terminate the unused input to VBB or use both pins differentially for best noise immunity.