Analog Devices Inc. LTC1272-8ACSW#TRPBF

Overview

LTC1272-8ACSW#TRPBF from Analog Devices (formerly Linear Technology) is a 12-bit, 8µs conversion time, single-supply successive approximation ADC with on-chip sample-and-hold and internal 2.42V reference. It operates from a 5V supply only, delivers up to 111kHz sampling rate, and maintains ±1 LSB integral linearity over 0°C to 70°C. It serves as a drop-in replacement for AD7572 in unipolar 0V–5V data acquisition systems requiring fast, low-power digitization.

For engineers reviewing the LTC1272-8ACSW#TRPBF datasheet, LTC1272-8ACSW#TRPBF pinout, LTC1272-8ACSW#TRPBF application, or LTC1272-8ACSW#TRPBF equivalent, key selection considerations include its 8µs conversion time versus 3µs grade, SO Wide 24-pin package compatibility, single-supply operation eliminating negative rail requirements, and 2.42V reference output polarity reversal versus AD7572's –5.25V reference.

Technical Context

The LTC1272-8ACSW#TRPBF uses LTBiCMOS switched-capacitor architecture to integrate a 12-bit SAR core, precision sample-and-hold, and curvature-corrected bandgap reference. Its internal clock supports 1.6MHz crystal/resonator operation (LTC1272-8 variant), enabling 111kHz sustained sampling.

Control logic relies on synchronized CS/RD/HBEN inputs to initiate conversion and manage 12-bit parallel or two-byte 8-bit bus interface. BUSY output signals active conversion, while three-state outputs D11–D0/8 support multiplexed read access without external latches.

Key Specifications

Pinout & Package

Package: 24-lead plastic SO wide (SW), RoHS-compliant, JEDEC MS-013AC, 0.300" body width, 1.27mm pitch.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD7572KNZ, LTC1272-8ACSW#TRPBF eliminates negative supply dependency and adds S/H/reference integration; compared with LTC1273-8ACSW#TRPBF, it lacks internal oscillator but offers identical conversion performance and lower cost where external clock is already available.

Availability

LTC1272-8ACSW#TRPBF is available at Aetrix Electronics and suitable for industrial data acquisition, DSP front-end interfaces, and multiplexed sensor systems requiring stable component supply, long-lifecycle support, and RoHS-compliant packaging.

Supply support for LTC1272-8ACSW#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 semiconductors, serving industrial, automotive, communications, and healthcare markets.

The LTC1272 family was developed by Linear Technology (acquired by ADI in 2017) to deliver pin-compatible, enhanced-performance replacements for industry-standard ADCs like AD7572-targeting cost-sensitive, space-constrained data acquisition systems needing single-supply operation and integrated references.

FAQ

What is the maximum sampling rate achievable with the LTC1272-8ACSW#TRPBF?

The LTC1272-8ACSW#TRPBF supports a maximum sustained sampling rate of 111kHz, derived from its 8µs conversion time and minimum 1µs inter-conversion delay. This assumes optimal timing synchronization between CS/RD and CLK IN, with ≥40ns separation from clock edges to suppress feedthrough. At this rate, the device maintains 72dB S/(N+D) and 11.5 ENOBs for 10kHz input signals.

Does the LTC1272-8ACSW#TRPBF require an external clock source?

No-the LTC1272-8ACSW#TRPBF can operate with either an external 1.6MHz TTL/CMOS clock applied to CLK IN or an internal oscillator using a 1.6MHz crystal/resonator connected between CLK IN and CLK OUT. The internal oscillator eliminates need for external clock generation circuitry, though external clock offers greater frequency stability and jitter control in noise-sensitive applications.

How does the LTC1272-8ACSW#TRPBF handle reference decoupling compared to the AD7572?

The LTC1272-8ACSW#TRPBF provides a 2.42V reference output at Pin 2, requiring reversal of the reference bypass capacitor polarity versus AD7572's –5.25V output. Recommended decoupling is 10µF tantalum in parallel with 0.1µF ceramic directly at VREF-to-AGND. This configuration suppresses wideband noise and ensures <1 LSB code transition noise, critical for maintaining 12-bit linearity.

Can the LTC1272-8ACSW#TRPBF interface directly with an 8-bit microcontroller bus?

Yes-the LTC1272-8ACSW#TRPBF supports two-byte read mode via HBEN control: when HBEN = HIGH, D11–D8 output DB11–DB8 (upper nibble), and D7–D0/8 output DB7–DB0 (lower byte). This allows full 12-bit data capture using two consecutive 8-bit reads without external latches or glue logic, compatible with 8051, PIC, or AVR families.

What is the significance of Pin 23 (NC) on the LTC1272-8ACSW#TRPBF?

Pin 23 on the LTC1272-8ACSW#TRPBF is internally not connected and replaces the AD7572's –15V supply pin. It may be left floating or tied to ground for mechanical stability-but must never be connected to a negative voltage. Its presence preserves socket compatibility with AD7572 layouts while eliminating negative supply routing, simplifying power design and reducing risk of supply sequencing errors.