Analog Devices Inc. LTC1272-3CCN#PBF

Overview

LTC1272-3CCN#PBF from Analog Devices (formerly Linear Technology) is a 12-bit, 3 µs successive approximation ADC with on-chip sample-and-hold, single 5 V supply operation, and AD7572-pin-compatible 24-pin narrow DIP packaging. It delivers up to 250 kHz sampling rate, 2.42 V internal reference, and 72 dB S/(N+D) at 10 kHz input - enabling high-speed data acquisition in industrial instrumentation and DSP front-ends.

For engineers reviewing the LTC1272-3CCN#PBF datasheet, LTC1272-3CCN#PBF pinout, LTC1272-3CCN#PBF application, or LTC1272-3CCN#PBF equivalent, key selection criteria include unipolar 0 V–5 V input range compatibility, 12-bit no-missing-codes performance, 3 µs conversion time, and drop-in replacement capability for AD7572-based designs requiring single-supply simplification.

Technical Context

The LTC1272-3CCN#PBF implements a switched-capacitor SAR architecture with integrated 2.42 V ±1% bandgap reference and precision sample-and-hold. Its internal DAC uses binary-weighted capacitors, and conversion timing is synchronized to a 4 MHz external clock or crystal oscillator connected between CLK IN and CLK OUT pins.

It supports two digital interface modes: parallel 12-bit read (HBEN = LOW) and multiplexed 8-bit byte reads (HBEN = HIGH), with BUSY output indicating conversion status. The device requires no negative supply - Pin 23 (NC) is internally unconnected, distinguishing it from AD7572's –15 V requirement.

Key Specifications

Pinout & Package

Package: 24-lead plastic DIP (narrow), 0°C to 70°C operating temperature range, JEDEC MS-001 compliant.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 12-bit SAR ADC applications.

Compared with AD7572KNZ and MAX1113ECPP+, the LTC1272-3CCN#PBF uniquely combines AD7572 pin compatibility, single 5 V operation, on-chip S/H, and 3 µs conversion - making it the only drop-in upgrade path for high-throughput, unipolar industrial ADC applications without board rework.

Availability

LTC1272-3CCN#PBF is available at Aetrix Electronics and suitable for industrial data acquisition, DSP front-end interfacing, and multiplexed sensor systems requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for LTC1272-3CCN#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 digital signal processing technologies.

The LTC1272 series was designed as a pin-compatible, performance-enhanced successor to the AD7572 for high-speed, single-supply data acquisition systems in industrial and test equipment.

FAQ

What is the maximum sampling rate supported by the LTC1272-3CCN#PBF?

The LTC1272-3CCN#PBF supports a maximum sustained sampling rate of 250 kHz, enabled by its 3 µs conversion time and integrated sample-and-hold. This rate assumes proper timing synchronization between CLK IN and RD/CS signals, with ≥1 µs delay between conversions to ensure full analog input acquisition. At this rate, the device maintains 72 dB S/(N+D) and 11.5 ENOB up to 20 kHz input frequency.

Can the LTC1272-3CCN#PBF replace an AD7572 in an existing design without PCB changes?

Yes, the LTC1272-3CCN#PBF is designed as a direct drop-in replacement for the AD7572 in 24-pin DIP sockets. Required modifications are minimal: reverse polarity of the reference bypass capacitor (10 µF tantalum) and leave Pin 23 (NC) unconnected instead of applying –15 V. No PCB layout or trace changes are needed, preserving mechanical and electrical compatibility.

What reference voltage does the LTC1272-3CCN#PBF provide, and how is it used?

The LTC1272-3CCN#PBF provides a 2.42 V ±1% internal reference at Pin 2 (VREF), with 25 ppm/°C temperature coefficient. This reference powers the internal DAC and is available for external decoupling using a 10 µF tantalum capacitor in parallel with a 0.1 µF ceramic capacitor. It replaces the –5.25 V reference of the AD7572 and must be connected with reversed polarity when retrofitting into AD7572 sockets.

How does the HBEN pin affect data output formatting on the LTC1272-3CCN#PBF?

The HBEN (High-Byte Enable) pin on the LTC1272-3CCN#PBF controls data bus multiplexing: when HBEN = LOW, all 12 bits (DB11–DB0) appear on D11–D0/8 for parallel read; when HBEN = HIGH, only the upper 4 bits (DB11–DB8) appear on D11–D8, while D7–D0/8 output LOW, enabling two 8-bit byte reads. This allows seamless interfacing with both 8-bit and 16-bit microcontrollers without external logic.

What are the absolute maximum ratings for analog input voltage on the LTC1272-3CCN#PBF?

The absolute maximum analog input voltage rating for the LTC1272-3CCN#PBF is –0.3 V to 15 V, per the Absolute Maximum Ratings table. However, the specified operational input range is strictly 0 V to 5 V unipolar. Inputs below 0 V are clamped by an internal diode and can sustain >60 mA sink current without latch-up, but accurate conversion is only guaranteed within the 0–5 V range.