Analog Devices Inc. LTC1536CS8#TRPBF

Overview

LTC1536CS8#TRPBF from Analog Devices (formerly Linear Technology) is a precision triple supply monitor IC designed for PCI local bus applications. It simultaneously monitors 5V (±5%), 3.3V (±0.3V), and an adjustable input (e.g., 1V ±0.75% threshold accuracy), delivers active-high and active-low reset outputs, and guarantees correct RST state down to VCC3 ≥ 1V or VCC5 ≥ 1V - critical for motherboard power sequencing and PCI tFAIL compliance.

For engineers reviewing the LTC1536CS8#TRPBF datasheet, LTC1536CS8#TRPBF pinout, LTC1536CS8#TRPBF application, or LTC1536CS8#TRPBF equivalent, key selection considerations include guaranteed ±0.75% threshold accuracy across temperature, 200ms internal reset delay, 100µA typical supply current, fast undervoltage response (tFAIL ≤ 450ns), and dual-mode pushbutton reset (100µs soft reset or 200ms hard reset).

Technical Context

The LTC1536CS8#TRPBF employs dual-comparator architecture per supply rail: a high-accuracy slow comparator for precise threshold detection and a faster comparator offset by 250mV for rapid PCI tFAIL response. Its gate drive circuitry automatically selects VCC3 or VCC5 as the RST output pull-down source, ensuring valid reset assertion as soon as either supply reaches 1V.

It integrates manual reset debouncing (35ms typical), supports OR-tie of SRST/RST with other open-drain sources, and features glitch-immune power-fail detection that triggers within 13µs of undervoltage onset. The VCCA input operates as a high-impedance 1V logic threshold or adjustable supply monitor, enabling flexible "power good" integration.

Key Specifications

Pinout & Package

Package: 8-pin SO (Small Outline, narrow 0.150″ body), RoHS-compliant, lead-free, tape-and-reel (#TRPBF). Pin pitch: 0.050″ (1.27mm), body width: 0.150–0.157″ (3.81–3.99mm).

Key Features

Applications

Equivalent & Alternatives

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

Compared with LTC1326CMS8#TRPBF and TPS3808G33DBVR, the LTC1536CS8#TRPBF uniquely delivers PCI-compliant tFAIL response, automatic VCC3/VCC5 gate-drive selection, and true triple-rail monitoring in a single 8-pin SO package - making it irreplaceable for PCI-based motherboard and expansion card designs requiring guaranteed timing and mixed-voltage robustness.

Availability

LTC1536CS8#TRPBF is available at Aetrix Electronics and suitable for PCI expansion board design, desktop/notebook motherboard power sequencing, and intelligent instrument power-fail recovery requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for LTC1536CS8#TRPBF 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 its precision analog portfolio. Linear pioneered high-accuracy voltage monitoring ICs with sub-1% threshold tolerance and industry-leading glitch immunity.

The LTC1536CS8#TRPBF belongs to Linear's PCI-optimized supply monitor product line, engineered specifically for reliable reset generation in multi-rail computing platforms where timing compliance, low power, and mixed-voltage interoperability are mandatory.

FAQ

What is the operating temperature range of the LTC1536CS8#TRPBF?

The LTC1536CS8#TRPBF is rated for 0°C to 70°C (commercial grade). This range is validated per the LTC1536C part number designation and covers standard desktop, notebook, and peripheral card environments without thermal derating. The device maintains ±0.75% threshold accuracy and 200ms reset timing across this full span.

Does the LTC1536CS8#TRPBF support OR-tie of multiple reset sources?

Yes - the LTC1536CS8#TRPBF's RST (Pin 6) and SRST (Pin 7) outputs are open-drain with internal 6µA pull-ups to VCC3. This allows direct wire-OR connection with other open-drain reset sources (e.g., watchdog timers or supervisory ICs) without external diodes or logic, simplifying system-level reset arbitration.

How does the LTC1536CS8#TRPBF achieve PCI tFAIL compliance?

The LTC1536CS8#TRPBF achieves tFAIL ≤ 450ns via dual-comparator architecture: a fast comparator set 250mV below the main threshold detects rapid supply collapse, while the precision comparator ensures accurate long-term monitoring. This design meets PCI Local Bus Spec Rev 2.1 Section 4.3.2 without external components.

Can the VCCA pin of the LTC1536CS8#TRPBF monitor voltages other than 1V?

Yes - the VCCA pin is a high-impedance input with a nominal 1V threshold, but it can monitor any voltage using an external resistor divider. For example, tying VCCA to a DC/DC converter's feedback node enables precise tracking of regulated output voltage, extending the LTC1536CS8#TRPBF's utility beyond fixed-rail monitoring.

What is the minimum supply voltage required for the LTC1536CS8#TRPBF to assert a valid reset?

The LTC1536CS8#TRPBF guarantees correct RST logic state (low) for VCC3 ≥ 1V or VCC5 ≥ 1V. This means reset remains asserted even as supplies decay below nominal levels - a critical feature for brownout protection in systems where 3.3V or 5V rails may sag independently during power failure.