Analog Devices Inc. LTC1286IS8#PBF

Overview

LTC1286IS8#PBF from Analog Devices is a micropower, 12-bit successive approximation ADC with differential analog input, on-chip sample-and-hold, and SPI/Microwire-compatible 3-wire serial interface. It operates from 4.5V to 9V, draws 250µA typical supply current during conversion at 12.5 ksps, and auto-shuts down to 1nA typical when idle. It is used in battery-operated remote data acquisition systems where low quiescent power and direct sensor interfacing are critical.

For engineers reviewing the LTC1286IS8#PBF datasheet, LTC1286IS8#PBF pinout, LTC1286IS8#PBF application, or LTC1286IS8#PBF equivalent, key selection factors include guaranteed ±3/4 LSB max DNL, 60µs conversion time, single-supply operation up to 9V, differential input architecture enabling ratiometric measurement, and SO-8 package compatibility with space-constrained industrial sensing nodes.

Technical Context

The LTC1286IS8#PBF implements a switched-capacitor SAR architecture with integrated sample-and-hold, supporting unipolar transfer characteristics and external reference configuration via VREF pin. Its differential input stage accepts common-mode voltages up to VCC and supports reduced full-scale spans (down to 1.5V), enabling direct connection to transducers without gain stages.

Serial communication uses a synchronous 3-wire interface (CS/SHDN, CLK, DOUT) with MSB-first output timing, no DIN required. Conversion is initiated by CS falling edge; after one null bit, 12-bit result shifts out on DOUT synchronized to CLK falling edges - compatible with 8051, PIC, and ARM microcontrollers without level-shifting.

Key Specifications

Pinout & Package

Package: 8-lead plastic SOIC (S8), 150°C max junction temperature, θJA = 130°C/W.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ADS7822U and MAX11131ASA+, the LTC1286IS8#PBF uniquely combines 9V tolerance, true 1 nA shutdown, and differential input architecture - making it optimal for long-life, wide-supply, noise-immune sensor interfaces where precision and power coexist.

Availability

LTC1286IS8#PBF is available at Aetrix Electronics and suitable for battery-operated systems, remote data acquisition, and handheld terminal interface applications requiring stable component supply and long-term obsolescence management.

Supply support for LTC1286IS8#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 is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving industrial, automotive, communications, and healthcare markets.

The LTC1286IS8#PBF belongs to the LTC® micropower precision ADC family, designed specifically for energy-constrained sensing applications demanding accuracy, low voltage operation, and minimal external components.

FAQ

What is the maximum clock frequency supported by the LTC1286IS8#PBF?

The LTC1286IS8#PBF supports up to 200 kHz clock frequency at 5V supply. At higher supply voltages (e.g., 9V), maximum clock frequency increases slightly per the datasheet curve, but 200 kHz remains the recommended limit for guaranteed timing compliance across temperature and process variation. Exceeding this may cause conversion errors due to insufficient comparator settling time.

Does the LTC1286IS8#PBF require an external reference voltage?

Yes, the LTC1286IS8#PBF requires an external reference voltage applied to the VREF pin. It does not include an internal reference. The VREF pin accepts 1.5V to 5.55V, enabling flexible scaling - for example, using a 2.5V precision reference yields 610 µV LSB resolution, while a 5V reference gives 1.22 mV LSB.

Can the LTC1286IS8#PBF operate from a 3.3V supply?

No, the LTC1286IS8#PBF has a minimum supply voltage of 4.5V and is not rated for 3.3V operation. For 3.3V systems, Analog Devices offers the pin-compatible LTC1285IS8#PBF - a functionally identical 12-bit micropower ADC optimized for 2.7V–5.5V supplies.

How does the LTC1286IS8#PBF achieve 1 nA shutdown current?

The LTC1286IS8#PBF achieves 1 nA shutdown current by fully disabling its internal bias circuitry, comparator, and reference input buffer when CS/SHDN is held high (at VCC). This deep shutdown state is verified across temperature and process corners, and does not require stopping the clock or resetting other pins - simply driving CS to VCC suffices.

Is the LTC1286IS8#PBF compatible with SPI mode 0 (CPOL=0, CPHA=0)?

Yes, the LTC1286IS8#PBF is compatible with SPI mode 0. Data is sampled on the rising edge of CLK and shifted out on the falling edge, with MSB first. The device requires no configuration word, and CS must go low before the first CLK pulse to initiate conversion - matching standard SPI mode 0 timing requirements.