Analog Devices Inc. LTC2157CUP-14#TRPBF

Overview

LTC2157CUP-14#TRPBF from Analog Devices (acquired Linear Technology) is a dual-channel, 14-bit, 250Msps analog-to-digital converter with DDR LVDS outputs, 1.25GHz full-power bandwidth, 70dB SNR, and 90dB SFDR - designed for high-frequency undersampling in cellular basestations and software-defined radios.

For engineers reviewing the LTC2157CUP-14#TRPBF datasheet, LTC2157CUP-14#TRPBF pinout, LTC2157CUP-14#TRPBF application, or LTC2157CUP-14#TRPBF equivalent, key selection criteria include sampling rate headroom at 250Msps, low-latency 6-cycle pipeline, 1.8V single-supply operation, and compatibility with high-speed DDR LVDS FPGA interfaces.

Technical Context

The LTC2157CUP-14#TRPBF implements a pipelined ADC architecture with integrated sample-and-hold (S/H) front-end, correction logic, and DDR LVDS output drivers. Its 1.25GHz input bandwidth enables direct RF sampling of IF signals up to 122MHz with <70dB SNR.

It features a programmable clock duty cycle stabilizer, serial SPI configuration port, and dual independent analog input channels (AINA±, AINB±) with 1.5VP-P differential range and VCM bias generation. Latency is fixed at six clock cycles with no variation across temperature or supply.

Key Specifications

Pinout & Package

64-pin (9mm × 9mm) plastic QFN package with exposed thermal pad (Pin 65 = GND), requiring soldering to PCB ground plane for thermal and electrical integrity. Dual 1.8V supplies: VDD (analog) and OVDD (output driver).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual-channel, high-speed ADC applications.

Compared with AD9680BCPZ-500, LTC2157CUP-14#TRPBF offers lower power and simpler LVDS interfacing but trades off half the sampling rate and lacks JESD204B serialization; versus LTC2268-14IUP#PBF, it delivers 2× speed, deterministic latency, and flexible configuration at higher component cost and layout complexity.

Availability

LTC2157CUP-14#TRPBF is available at Aetrix Electronics and suitable for cellular infrastructure, defense SDR, medical imaging, and automated test equipment requiring stable component supply and long-term production continuity.

Supply support for LTC2157CUP-14#TRPBF 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

Analog Devices, Inc. (ADI) is a global leader in high-performance analog, mixed-signal, and digital signal processing technologies, serving communications, industrial, automotive, and healthcare markets.

The LTC2157 series belongs to ADI's high-speed data converter product line, engineered specifically for demanding RF digitization applications where dynamic range, bandwidth, and low latency are critical - including 5G infrastructure and electronic warfare systems.

FAQ

What is the maximum sampling rate supported by the LTC2157CUP-14#TRPBF?

The LTC2157CUP-14#TRPBF supports a maximum sampling rate of 250Msps, validated across the 0°C to 70°C operating temperature range. This rate is specified under recommended conditions: 1.8V supplies, differential ENC+/ENC– clock, and 1.5VP-P analog input. Performance metrics including 70dB SNR and 90dB SFDR are guaranteed at this rate for input frequencies up to 140MHz.

Does the LTC2157CUP-14#TRPBF require separate analog and digital supplies?

No - the LTC2157CUP-14#TRPBF uses a single 1.8V analog supply (VDD) and a separate 1.8V output driver supply (OVDD), both rated from 1.7V to 1.9V. VDD powers the ADC core and S/H circuitry, while OVDD powers the DDR LVDS output drivers. Both supplies must be independently bypassed with 0.1µF ceramic capacitors, and OGND pins must be tied to system ground.

How does the DDR LVDS interface of the LTC2157CUP-14#TRPBF reduce FPGA I/O usage?

The LTC2157CUP-14#TRPBF uses double-data-rate LVDS signaling: each differential pair carries two bits per clock edge (even bits on CLKOUT+ low, odd bits on high), reducing the required pin count by 50% versus single-data-rate. For its 14-bit dual channels, it needs only 14 LVDS pairs (28 pins) plus CLKOUT±, versus 56+ pins for SDR - directly easing routing and timing closure on high-density FPGAs like Xilinx Ultrascale+.

Can the LTC2157CUP-14#TRPBF operate with an external voltage reference?

Yes - applying 1.200V to 1.300V to the SENSE pin selects external reference mode, setting the input range to ±0.6 × VSENSE (e.g., ±0.72V for 1.2V reference). In this mode, the internal 1.25V VREF output is disabled, and the SENSE pin leakage remains ≤±1µA. The device retains full DC specs (±0.85LSB INL, ±0.25LSB DNL) and AC performance when properly decoupled.

What power-saving modes does the LTC2157CUP-14#TRPBF support, and how are they activated?

The LTC2157CUP-14#TRPBF supports Sleep Mode (<5mW) and Nap Mode (213mW at 250Msps), both activated via its SPI interface. Sleep Mode disables the ADC core and clocks; Nap Mode reduces bias currents while retaining fast wake-up. Activation requires writing to specific mode control registers using the serial interface (PAR/SER = GND, CS/SCK/SDI configured per datasheet Table 2), with no external pin toggling needed.