Analog Devices Inc. LTC1843IS8#PBF

Overview

LTC1843IS8#PBF from Analog Devices (formerly Linear Technology) is an ultralow power dual comparator with integrated 1.182V ±1% voltage reference, open-drain outputs capable of sinking >20mA, and programmable hysteresis via HYST pin. It operates from a single 2.5V–11V supply, features 3.5µA typical supply current at 25°C, and supports battery-powered threshold detection in portable instrumentation and power management systems.

For engineers reviewing the LTC1843IS8#PBF datasheet, LTC1843IS8#PBF pinout, LTC1843IS8#PBF application, or LTC1843IS8#PBF equivalent, key selection criteria include its guaranteed –40°C to +85°C operating range, 12µs propagation delay with 10mV overdrive, input common-mode range extending to V– and within 1.3V of V+, and stable 0.01µF reference bypassing capability without oscillation.

Technical Context

The LTC1843IS8#PBF implements two independent comparators with rail-to-rail input stages referenced to V–, where IN A+ and IN B– serve as active inputs in its specific SO-8 pinout configuration. Its internal bandgap reference delivers 1.182V ±1.5% over –40°C to +85°C and drives external capacitive loads up to 0.01µF without compensation.

Hysteresis is implemented externally using two resistors between REF, HYST, and V–, enabling adjustable threshold bands up to 100mV total (±50mV around VREF). The open-drain outputs support wired-OR logic and level shifting, with output low voltage specified at V– + 0.4V @ 0.8mA sink current.

Key Specifications

Pinout & Package

Package: SO-8 (8-lead plastic small outline, narrow 0.150", JEDEC MS-012AC).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual comparator with reference applications.

Compared with LTC1442CS8#PBF, LTC1843IS8#PBF offers lower supply current and field-adjustable hysteresis; compared with LTC1842IS8#PBF, it provides inverting B-input for direct low-threshold detection without signal inversion.

Availability

LTC1843IS8#PBF is available at Aetrix Electronics and suitable for battery-powered system monitoring, threshold detectors, window comparators, and oscillator circuits requiring stable component supply across industrial temperature ranges.

Supply support for LTC1843IS8#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 acquired Linear Technology in 2017 and maintains full product support, manufacturing, and documentation for legacy Linear parts including the LTC series.

The LTC1843IS8#PBF belongs to Linear's ultralow power comparator family designed specifically for energy-constrained applications such as portable medical devices, remote sensors, and battery-backed industrial controllers.

FAQ

What is the operating temperature range for the LTC1843IS8#PBF?

The LTC1843IS8#PBF is rated for operation from –40°C to +85°C, as indicated by the "I" grade suffix in the part number. This extended industrial temperature range ensures reliable performance in automotive cabin modules, outdoor IoT nodes, and industrial control panels where ambient conditions vary widely. The reference voltage drift remains within ±1.5% across this full range.

Can the LTC1843IS8#PBF drive a 0.01µF capacitor directly on its REF pin?

Yes, the LTC1843IS8#PBF reference output is explicitly characterized to drive up to 0.01µF bypass capacitors without oscillation, per the datasheet Figure 2 and Applications Information section. This eliminates the need for external series resistors in most designs. For larger capacitors (up to 100µF), a damping resistor must be added in series with the REF pin per the recommended circuit in Figure 1.

How is hysteresis programmed on the LTC1843IS8#PBF?

Hysteresis on the LTC1843IS8#PBF is programmed using two external resistors: one between REF and HYST pins (R1), and another between HYST and V– (R2). The hysteresis voltage band equals twice the voltage difference between REF and HYST, with a maximum allowable difference of 50mV (yielding up to 100mV total hysteresis). If unused, HYST must be shorted to REF.

What is the maximum sink current capability of the LTC1843IS8#PBF outputs?

The LTC1843IS8#PBF open-drain outputs can typically sink greater than 20mA each, as confirmed in the Features list and Absolute Maximum Ratings table. At 5V supply, short-circuit sink current exceeds 120mA (Figure G03), and output low voltage is specified at V– + 0.4V with 0.8mA load. This supports direct LED driving or MOSFET gate control without buffer stages.

Does the LTC1843IS8#PBF require separate power supplies for the reference and comparators?

No, the LTC1843IS8#PBF uses a single supply rail (V+) for both the comparators and the internal 1.182V reference. The reference is derived from the same V+ input and referenced to V–, eliminating the need for auxiliary supplies. The reference output remains stable across the full 2.5V–11V V+ range and does not require decoupling beyond standard 0.1µF at V+.