Analog Devices Inc. DC045A

Overview

DC045A from Linear Technology (now Analog Devices) is a micropower 12-bit successive approximation ADC in an 8-pin SOIC package, featuring differential analog input (LTC1286 variant), on-chip sample-and-hold, 60 µs conversion time, and auto shutdown to 1 nA typical supply current. It operates from 4.5 V to 9 V and supports SPI/Microwire-compatible serial interface - ideal for battery-powered remote data acquisition systems requiring high resolution and ultra-low quiescent power.

For engineers reviewing the DC045A datasheet, DC045A pinout, DC045A application, or DC045A equivalent, this page delivers verified technical context, real-world design meaning of key specs, validated pin functions, confirmed application use cases, and two rigorously cross-checked alternative parts with documented functional and application-level differences.

Technical Context

The DC045A implements a switched-capacitor SAR architecture with integrated sample-and-hold, enabling precise ratiometric or externally referenced measurements. Its differential input stage supports common-mode voltages up to VCC and allows reduced full-scale spans down to 1.5 V, yielding 244 µV resolution at 5 V reference.

It uses a 3-wire synchronous serial interface (CS/CLK/DOUT) with MSB-first output, no DIN required, and automatic power-down between conversions. Conversion is initiated by CS falling edge; DOUT becomes active after one null bit, delivering 12-bit data without configuration overhead.

Key Specifications

Pinout & Package

DC045A is housed in an 8-lead plastic SOIC (S8) package, 3.9 mm × 4.9 mm, 1.27 mm pitch, JEDEC MS-012AC compliant. Thermal resistance θ_JA = 130°C/W (C-grade) or 175°C/W (I-grade).

Key Features

Applications

Equivalent & Alternatives

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

Compared with ADS7822U and LTC1864LCS8, DC045A uniquely balances 4.5–9 V operation, true differential input, external reference capability, and sub-µA shutdown - making it the only choice for legacy 9 V battery-powered instrumentation requiring precision and ultra-low standby drain.

Availability

DC045A is available at Aetrix Electronics and suitable for battery-operated systems, remote data acquisition nodes, and isolated industrial sensor interfaces requiring stable component supply across extended product lifecycles.

Supply support for DC045A 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 (formerly Linear Technology) designs high-performance analog, mixed-signal, and RF ICs for precision measurement, power management, and signal conditioning.

The DC045A belongs to the LTC1286 family of micropower SAR ADCs, engineered specifically for ultra-low-power, high-resolution data acquisition in portable, remote, and energy-constrained systems - emphasizing shutdown efficiency, analog input flexibility, and minimal external component count.

FAQ

What is the maximum clock frequency supported by DC045A?

The DC045A supports a maximum clock frequency of 200 kHz when operating from a 5 V supply. At higher supply voltages (up to 9 V), the maximum clock frequency increases slightly - e.g., ~290 kHz at 8 V - as confirmed in the Typical Performance Characteristics curve "Maximum Clock Frequency vs Supply Voltage". Exceeding these limits risks conversion errors due to insufficient comparator settling time.

Does DC045A require an external reference voltage?

Yes, DC045A (as the LTC1286 variant) features a dedicated VREF pin and requires an external reference voltage to define its full-scale range. It does not include an internal reference. The reference can be a precision bandgap source, a low-drift voltage reference IC, or a ratiometric tap from the same supply powering the sensor - enabling flexible system-level accuracy calibration.

Can DC045A operate from a 3.3 V supply?

No, DC045A cannot operate from a 3.3 V supply. Its absolute minimum supply voltage is 4.5 V, and it is specified for operation from 4.5 V to 9 V. For 3.3 V systems, consider alternatives such as the LTC1864LCS8 or ADS7822U - both explicitly rated for 2.7–5.25 V operation and pin-compatible in SOIC-8 packages.

How does DC045A achieve 1 nA shutdown current?

DC045A achieves 1 nA typical shutdown current by driving the CS/SHDN pin high (to VCC), which gates off internal bias circuits, disables the comparator, and places the reference input in high-impedance mode. This hardware-controlled shutdown requires no software initialization or register writes - making it inherently robust for fail-safe low-power modes in safety-critical or energy-harvesting applications.

Is DC045A compatible with SPI bus timing?

Yes, DC045A is compatible with standard SPI bus timing in master-slave configurations, though it uses a simplified 3-wire interface (CS/CLK/DOUT) without DIN. It outputs MSB-first data on DOUT synchronized to the falling edge of CLK, with setup/hold times (e.g., t_suCS = 2 µs, t_WHCLK = 2 µs) fully compliant with common microcontrollers including STM32, PIC, and MSP430 families - requiring no custom bit-banging firmware.