Analog Devices Inc. LTC1401IS8#PBF

Overview

LTC1401IS8#PBF from Analog Devices (formerly Linear Technology) is a 12-bit, 200ksps successive-approximation ADC with integrated 1.2V reference, SO-8 package, single 3V supply operation, and 3-wire SPI/MICROWIRE-compatible serial interface. It delivers ±1LSB INL/DNL, 68dB S/(N+D) at 50kHz, and operates across –40°C to +85°C for industrial data acquisition systems.

For engineers reviewing the LTC1401IS8#PBF datasheet, LTC1401IS8#PBF pinout, LTC1401IS8#PBF application, or LTC1401IS8#PBF equivalent, key selection criteria include unipolar 0V–2.048V input range, Nap/Sleep/Shutdown power modes (1.5mW / 19.5µW / 13.5µW), 315ns acquisition time, and REFRDY signal for reference settling confirmation.

Technical Context

The LTC1401IS8#PBF implements a capacitive DAC-based successive approximation architecture with an internal sample-and-hold circuit. Its conversion timing is synchronized by external CLK (0.1–3.2MHz), initiated by CONV rising edge, and outputs a 13-bit serial word (REFRDY + 12-bit data) on DOUT.

It features three low-power states controlled via dedicated pins: SHDN forces Shutdown mode (13.5µW); CONV pulse sequences with CLK low enable Nap (350ns wake-up) or Sleep (3ms VREF wake-up). The internal 1.2V bandgap reference supports external overdrive up to 3V and exhibits ±10ppm/°C tempco.

Key Specifications

Pinout & Package

Package: 8-lead plastic SO (SO-8), 150mil width, JEDEC MS-012AC. Pin 1 marked with dot or bevel; pin numbering counterclockwise from top-left corner when viewed from top.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ADS7822U and MAX11131AUT+, the LTC1401IS8#PBF uniquely combines industrial temperature range, integrated low-drift reference, and multi-mode power control-making it optimal for embedded instrumentation where reliability, self-contained operation, and adaptive energy use are mandatory.

Availability

LTC1401IS8#PBF is available at Aetrix Electronics and suitable for portable instrumentation, industrial sensor interfaces, and telecom monitoring systems requiring stable component supply with long-term lifecycle assurance.

Supply support for LTC1401IS8#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 semiconductors.

The LTC1401IS8#PBF belongs to Linear's legacy precision data acquisition product line, designed specifically for low-power, high-accuracy industrial and portable measurement applications where integration, temperature stability, and ease of use are prioritized.

FAQ

What is the operating temperature range of the LTC1401IS8#PBF?

The LTC1401IS8#PBF is rated for –40°C to +85°C ambient operation (I-grade), verified per manufacturer specifications. This industrial temperature range ensures reliable performance in factory automation, outdoor telemetry, and automotive under-hood monitoring applications where thermal extremes are common. All key AC/DC parameters-including INL, DNL, S/(N+D), and reference tempco-are guaranteed across this full range.

Does the LTC1401IS8#PBF require an external reference?

No, the LTC1401IS8#PBF includes a factory-trimmed, temperature-compensated 1.200V internal reference accessible at Pin 3 (VREF). It supports up to 1mA load and exhibits ±10ppm/°C full-scale drift. External reference is optional-for example, to extend input range using an overdriven LT1634-1.25-but not required for standard 0V–2.048V unipolar operation.

How does the REFRDY signal function in the LTC1401IS8#PBF?

The REFRDY signal is the first bit of the 13-bit serial output word from the LTC1401IS8#PBF. It asserts high once the internal reference has settled after exiting Sleep or Shutdown mode-typically within 3ms with a 10µF bypass capacitor. This allows firmware to synchronize conversion initiation precisely, avoiding invalid data reads during reference ramp-up.

Can the LTC1401IS8#PBF interface directly with a TMS320C50 DSP?

Yes, the LTC1401IS8#PBF is explicitly validated for direct interface with the TMS320C50 DSP using its 3-wire serial protocol (CLK, CONV, DOUT). Application Note 1401 TA04a shows frame-sync generation from TFSX and right-justified data loading into the TRCV register-no level-shifting or protocol translation is needed when both devices operate from compatible 3V supplies.

What are the timing requirements for entering Nap mode on the LTC1401IS8#PBF?

To enter Nap mode, hold CLK low and apply two consecutive pulses to the CONV pin; Nap activation occurs on the falling edge of the second CONV pulse. Wake-up latency is 350ns from CLK rising edge to valid DOUT data. This sequence is deterministic and does not require polling-enabling ultra-low-latency resumption of sampling in responsive data loggers or event-triggered acquisition systems.