Analog Devices Inc. LTC2308CUF#PBF

Overview

LTC2308CUF#PBF from Analog Devices (formerly Linear Technology) is a low-noise, 500ksps, 8-channel, 12-bit successive approximation register (SAR) ADC with integrated 2.5V reference, 8-channel analog multiplexer, and SPI/MICROWIRE-compatible serial interface. It operates from a single 5V supply, draws 3.5mA at full rate, supports unipolar (0–4.096V) or bipolar (±2.048V) input ranges, and is housed in a 24-pin 4mm × 4mm QFN package - ideal for high-density data acquisition in portable instrumentation.

For engineers reviewing the LTC2308CUF#PBF datasheet, LTC2308CUF#PBF pinout, LTC2308CUF#PBF application, or LTC2308CUF#PBF equivalent, key selection criteria include guaranteed no missing codes, 73.3dB SINAD at 1kHz, 500ksps throughput with internal conversion clock, auto-shutdown scaling from 3.5mA to 200µA, and software-selectable input configuration across eight channels.

Technical Context

The LTC2308CUF#PBF implements a capacitive charge-redistribution SAR architecture with fully differential sample-and-hold, enabling common-mode noise rejection. Its internal 2.5V bandgap reference is trimmed to ±0.3% initial accuracy and buffered to 4.096V at REFCOMP with ±25ppm/°C tempco.

Conversion is initiated by a rising edge on CONVST; the 6-bit DIN word (loaded via SDI on SCK rising edges) configures channel selection (CH0–CH7), single-ended/differential mode, unipolar/bipolar range, and sleep mode - all without interrupting continuous operation.

Key Specifications

Pinout & Package

Package: 24-lead (4mm × 4mm) plastic QFN (UF package) with exposed pad (Pin 25) soldered to GND for thermal and electrical performance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LTC2308CUF#PBF, ADS8688IPWR delivers higher resolution at the cost of higher static power and no sleep mode, while MAX11131ETL+ offers compact size and lower cost but sacrifices bipolar operation, reference flexibility, and dynamic performance - making LTC2308CUF#PBF optimal for balanced precision, power, and configurability in portable and industrial systems.

Availability

LTC2308CUF#PBF is available at Aetrix Electronics and suitable for industrial process control, motor control feedback, battery-powered test equipment, and isolated data acquisition requiring stable component supply across extended production lifecycles.

Supply support for LTC2308CUF#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. (ADI) is a global leader in high-performance analog, mixed-signal, and digital signal processing technologies, serving industrial, automotive, communications, and healthcare markets.

The LTC2308CUF#PBF belongs to ADI's precision data acquisition portfolio, designed specifically for space-constrained, low-power, multi-channel measurement systems requiring integrated references and flexible input configuration without external support components.

FAQ

What is the operating temperature range for the LTC2308CUF#PBF?

The LTC2308CUF#PBF is rated for 0°C to 70°C ambient operation, as indicated by the "C" grade suffix in its part number. This commercial-grade specification ensures reliable performance in non-extended environments such as laboratory instruments, consumer test gear, and indoor industrial controllers. The LTC2308CUF#PBF does not support –40°C to 85°C operation - that range applies only to the "I" grade variant (e.g., LTC2308IUF#PBF).

Does the LTC2308CUF#PBF require an external reference, or is the internal reference sufficient for precision applications?

The LTC2308CUF#PBF includes a factory-trimmed 2.5V internal reference with ±0.3% initial accuracy and ±25ppm/°C tempco, buffered to 4.096V at REFCOMP - sufficient for most 12-bit applications including sensor interfaces and process monitoring. For higher accuracy or lower drift, the LTC2308CUF#PBF supports external reference overdrive at either VREF (2.5V) or REFCOMP (1V–AVDD), enabling use of precision external references like the LT6655.

How does the auto-shutdown feature of the LTC2308CUF#PBF scale power consumption with sample rate?

The LTC2308CUF#PBF dynamically scales supply current from 3.5mA at 500ksps down to 200µA at 1ksps and further to 35µW in Sleep Mode - all without firmware intervention. This is achieved through internal clock gating and bias current adjustment tied directly to the CONVST assertion frequency. The LTC2308CUF#PBF thus eliminates the need for external power sequencing logic in battery-operated or duty-cycled systems.

Can the LTC2308CUF#PBF perform true simultaneous sampling across all 8 channels?

No - the LTC2308CUF#PBF uses a single SAR core with an internal 8-channel multiplexer; it performs sequential sampling of selected channels, not simultaneous sampling. However, its 1.6µs max conversion time and 240ns acquisition window enable tightly interleaved sampling (e.g., sub-2µs channel-to-channel skew), which is adequate for many multi-sensor applications where true simultaneity is not required, such as temperature profiling or slow-varying industrial signals.

What are the absolute maximum ratings for analog input voltage on the LTC2308CUF#PBF?

The LTC2308CUF#PBF specifies an absolute maximum analog input voltage range of (GND – 0.3V) to (AVDD + 0.3V) for CH0–CH7, COM, REF, and REFCOMP pins. With AVDD = 5V, this translates to –0.3V to +5.3V. Exceeding these limits risks permanent damage. For safe operation, unipolar inputs must stay within 0V–4.096V and bipolar inputs within ±2.048V relative to COM - both enforced by the internal reference architecture of the LTC2308CUF#PBF.