Analog Devices Inc. LTC2175CUKG-12#PBF

Overview

LTC2175CUKG-12#PBF from Analog Devices (formerly Linear Technology) is a 12-bit, 125Msps quad simultaneous-sampling analog-to-digital converter optimized for high-dynamic-range RF/IF digitization in communications infrastructure. It delivers 70.6dB SNR, 88dB SFDR, and ultralow 0.15psRMS aperture jitter, enabling undersampling of 70MHz+ IF signals with clean spectral purity in cellular base stations and software-defined radios.

For engineers reviewing the LTC2175CUKG-12#PBF datasheet, LTC2175CUKG-12#PBF pinout, LTC2175CUKG-12#PBF application, or LTC2175CUKG-12#PBF equivalent, key selection criteria include its 4-channel simultaneous sampling capability, serial LVDS output architecture (1- or 2-lane), 1.8V single-supply operation, and 52-pin QFN package with integrated clock duty cycle stabilizer and SPI configuration interface.

Technical Context

The LTC2175CUKG-12#PBF implements four independent 12-bit ADC cores with shared sample-and-hold circuitry, each featuring 800MHz full-power bandwidth and differential analog inputs. Its internal PLL-free architecture relies on external encode clocking with optional duty cycle stabilization to maintain timing integrity across wide input duty cycles.

Digital output serialization uses LVDS drivers with selectable 1.75mA or 3.5mA current modes and configurable internal 100Ω termination. The device supports both internal and external reference configurations, with VCM outputs (VCM12/VCM34) providing precise common-mode bias for differential input pairs.

Key Specifications

Pinout & Package

52-pin (7mm × 8mm) plastic QFN package with exposed thermal pad (Pin 53 = GND). Requires soldering of exposed pad to PCB ground plane for thermal and electrical integrity.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar quad ADC applications.

Compared with AD9634BCPZ-125 and LTC2265IUKG-12#PBF, the LTC2175CUKG-12#PBF uniquely integrates quad simultaneous sampling with serial LVDS output in a single 52-pin QFN, reducing PCB area, interconnect count, and clock distribution complexity while preserving timing coherence essential for phased-array and MIMO systems.

Availability

LTC2175CUKG-12#PBF is available at Aetrix Electronics and suitable for cellular infrastructure, software-defined radio development, and portable medical imaging systems requiring stable component supply, long-term manufacturability, and guaranteed lead-free compliance.

Supply support for LTC2175CUKG-12#PBF 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. (acquired Linear Technology in 2017) is a global leader in high-performance analog, mixed-signal, and DSP technologies for precision instrumentation, communications, and industrial applications.

The LTC2175 series belongs to Linear Technology's high-speed data acquisition product line, designed specifically for RF/IF digitization in wireless infrastructure, defense electronics, and medical imaging where simultaneous multi-channel sampling, low jitter, and compact integration are critical.

FAQ

What is the maximum sampling rate supported by the LTC2175CUKG-12#PBF?

The LTC2175CUKG-12#PBF supports a maximum sampling rate of 125Msps, as confirmed in the Absolute Maximum Ratings and Converter Characteristics tables. This rate applies specifically to the LTC2175-12 speed grade, distinct from the 105Msps (LTC2174-12) and 80Msps (LTC2173-12) variants. Operation at 125Msps requires proper thermal management and adherence to specified supply voltage (1.7V–1.9V) and clock signal integrity requirements.

Does the LTC2175CUKG-12#PBF support external voltage reference operation?

Yes, the LTC2175CUKG-12#PBF supports both internal and external reference configurations. When using an external reference, the SENSE pin accepts 0.625V to 1.300V, and the device achieves ±0.2% gain matching and 0.3LSBRMS transition noise. External reference mode is selected via SPI register configuration and requires proper decoupling of the SENSE pin per the layout guidelines in the datasheet.

How many LVDS data lanes does the LTC2175CUKG-12#PBF use by default?

The LTC2175CUKG-12#PBF defaults to 2-lane LVDS output mode, delivering two serialized bits per channel per clock cycle. A 1-lane mode is also supported via SPI configuration or parallel programming (PAR/SER = VDD), reducing output pin count at the cost of doubled serial data rate. Both modes maintain the same 125Msps sampling rate and pipeline latency of 6 clock cycles.

What is the function of the VCM12 and VCM34 pins on the LTC2175CUKG-12#PBF?

VCM12 and VCM34 are dedicated common-mode bias outputs that provide a nominally VDD/2 voltage to set the input common-mode level for differential analog input pairs. VCM12 biases channels 1 and 2, while VCM34 biases channels 3 and 4. Each must be bypassed to ground with a 0.1µF ceramic capacitor to ensure stable common-mode rejection and minimize noise coupling into the LTC2175CUKG-12#PBF analog front end.

Can the LTC2175CUKG-12#PBF operate with a single-ended encode clock input?

Yes, the LTC2175CUKG-12#PBF supports single-ended encode clock operation by tying ENC– to GND and driving ENC+ with a 1.8V square wave or sine wave. In this mode, the device maintains full 125Msps performance and 70.6dB SNR, though differential drive is recommended for optimal jitter performance. Input thresholds are specified at VIH = 1.2V and VIL = 0.6V under 1.8V supply conditions.