Analog Devices Inc. LTC1727IS8-5#PBF

Overview

LTC1727IS8-5#PBF from Analog Devices is a micropower precision triple supply monitor IC for systems requiring simultaneous monitoring of 5V, 3.3V, and an adjustable voltage rail. It features three independent open-drain comparator outputs (COMP5, COMP3, COMPA), a common active-low reset output (RST) with 200ms delay, ±1.5% threshold accuracy over temperature, and guaranteed RST assertion down to VCC inputs ≥1V. It is used in notebook computers and intelligent instruments where reliable power sequencing and brownout detection are critical.

For engineers reviewing the LTC1727IS8-5#PBF datasheet, LTC1727IS8-5#PBF pinout, LTC1727IS8-5#PBF application, or LTC1727IS8-5#PBF equivalent, key selection considerations include its 8-lead SO package, individual supply monitoring capability (distinguishing it from LTC1728 variants), 10µA typical supply current, and support for configurable dual- or triple-supply monitoring schemes with glitch immunity.

Technical Context

The LTC1727IS8-5#PBF implements three independent comparators feeding into a 200ms reset timer and separate open-drain outputs. Its internal bandgap reference enables accurate threshold detection across –40°C to +85°C, and power is autonomously drawn from whichever supply (VCC5 or VCC3) exceeds the other - ensuring RST remains valid even during asymmetric power-up sequences.

Each comparator (COMP5, COMP3, COMPA) asserts high when its respective input exceeds its factory-trimmed threshold (VRT5 = 4.675V, VRT3 = 3.086V, VRTA = 1.000V), with weak internal 6µA pull-ups to VCC3. The RST output remains low until all three supplies exceed their thresholds and sustains the low state for ≥200ms after compliance, providing robust debouncing against supply transients.

Key Specifications

Pinout & Package

The LTC1727IS8-5#PBF is housed in an 8-lead plastic SO (Small Outline) package, 0.150-inch narrow body, with lead finish Pb-free (RoHS compliant). Pin spacing is 0.050" (1.27mm) pitch, and the package is rated for operation from –40°C to +85°C.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar triple supply monitoring applications.

Compared with LTC1727IS8-5#PBF, the LTC1728IS5-5#PBF reduces footprint and cost but sacrifices diagnostic visibility, while the LTC1326IS8-5#PBF adds watchdog and manual reset at the expense of higher quiescent current and reduced threshold stability.

Availability

LTC1727IS8-5#PBF is available at Aetrix Electronics and suitable for desktop computers, notebook computers, and intelligent instruments requiring stable component supply with guaranteed long-term availability and RoHS-compliant packaging.

Supply support for LTC1727IS8-5#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. is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving industrial, automotive, communications, and healthcare markets.

The LTC1727 belongs to Analog Devices' precision power monitoring product line, designed specifically for reliable multi-rail supervision in computing, instrumentation, and server platforms where deterministic reset behavior and minimal power overhead are essential.

FAQ

What is the operating temperature range for the LTC1727IS8-5#PBF?

The LTC1727IS8-5#PBF is specified for operation from –40°C to +85°C (Industrial grade). This range is validated per the device's electrical characteristics table and absolute maximum ratings, and applies to all performance parameters including threshold accuracy, reset delay, and supply current.

Does the LTC1727IS8-5#PBF support monitoring only three supplies, or can it be configured for fewer?

Yes, the LTC1727IS8-5#PBF can be configured to monitor one or two supplies instead of three. For example, tying VCCA to VCC3 disables the adjustable rail monitor, and connecting VCC5 to VCC3 (with diode isolation if needed) allows single-rail 3.3V or 5V monitoring - as documented in the Applications Information section.

How does the VCC5 override function work in the LTC1727IS8-5#PBF?

The VCC5 override function in the LTC1727IS8-5#PBF disables the 5V monitor when VCC5 is within ±25mV of VCC3 and <4.15V, allowing the device to behave as a 3.3V-only monitor. It re-enables above ~4.15V, enabling automatic mode switching between 3.3V and 5V supervision without external control logic.

What is the minimum supply voltage required to guarantee correct RST output state in the LTC1727IS8-5#PBF?

The LTC1727IS8-5#PBF guarantees correct RST logic state (low or high) for VCC3, VCC5, or VCCA ≥1V. Below 1V, RST is not guaranteed and may float or behave unpredictably - this is explicitly defined in the Absolute Maximum Ratings and Electrical Characteristics tables.

Can the LTC1727IS8-5#PBF drive a 5V logic interface directly?

Yes, the LTC1727IS8-5#PBF's RST and comparator outputs are open-drain and can be pulled up to 5V using an external resistor. The datasheet confirms compatibility with pull-ups >VCC3 (e.g., to 5V), and VOL remains ≤0.4V at ISINK = 2.5mA with VCC3 = 3V, ensuring solid low-state margin for 5V CMOS inputs.