Analog Devices Inc. LTC2901-4IGN#PBF

Overview

LTC2901-4IGN#PBF from Analog Devices (acquired Linear Technology) is a programmable quad supply monitor IC with push-pull RST output, 16-pin narrow SSOP package, ±1.5% voltage threshold accuracy over temperature, 5% or 10% selectable undervoltage tolerance, and adjustable reset/watchdog timing via external capacitors. It simultaneously supervises four independent supply rails (e.g., 5V, 3.3V, 2.5V, 1.8V) in multivoltage systems requiring reliable power-on reset and watchdog supervision.

For engineers reviewing the LTC2901-4IGN#PBF datasheet, LTC2901-4IGN#PBF pinout, LTC2901-4IGN#PBF application, or LTC2901-4IGN#PBF equivalent, key selection criteria include its push-pull RST output (vs open-drain variants), TOL pin for 5%/10% threshold selection, guaranteed RST operation down to VCC = 1V, 43μA typical supply current, and compatibility with adjustable ±ADJ monitoring configurations.

Technical Context

The LTC2901-4IGN#PBF implements four independent high-accuracy comparators with user-programmable thresholds selected via a resistor divider on the VPG pin. Its internal bandgap reference (1.210V ±1.5%) enables precise trip-point generation across 16 preset/adjustable combinations, including positive ADJ and negative ADJ modes for bipolar supply monitoring.

Reset assertion is synchronized to all monitored supplies; RST remains low until all inputs exceed their thresholds, then holds low for a capacitor-programmed delay (CRT). The watchdog function uses WDI edge detection and CWT timing - on timeout, LTC2901-4 asserts RST directly (no separate WDO pin), delivering a full system reset rather than a flag signal.

Key Specifications

Pinout & Package

Package: 16-lead narrow plastic SSOP (GN16), 0.15mm lead pitch, RoHS-compliant #PBF finish.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LTC2901-3IGN#PBF, the LTC2901-4IGN#PBF offers reduced external component count via push-pull RST, while TPS3808G33DBVR trades quad monitoring and programmability for smaller footprint and lower unit cost in simpler systems.

Availability

LTC2901-4IGN#PBF is available at Aetrix Electronics and suitable for desktop computers, telecom equipment, network servers, and portable battery-powered equipment requiring stable component supply, long-term lifecycle support, and guaranteed RoHS compliance.

Supply support for LTC2901-4IGN#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 semiconductors, serving industrial, automotive, communications, and healthcare markets.

The LTC2901 product line delivers precision, low-power, programmable supply monitoring for complex multivoltage systems - designed specifically to replace discrete reset circuits and simplify power sequencing in high-reliability computing and infrastructure applications.

FAQ

What is the key functional difference between LTC2901-4IGN#PBF and LTC2901-3IGN#PBF?

The LTC2901-4IGN#PBF features a push-pull RST output that actively drives high to V2, eliminating the need for an external pull-up resistor. In contrast, the LTC2901-3IGN#PBF uses an open-drain RST output requiring an external pull-up. Both share identical pinout, voltage thresholds, timing capabilities, and TOL functionality - the RST driver architecture is the sole distinguishing feature.

How does the TOL pin affect voltage threshold selection on LTC2901-4IGN#PBF?

On the LTC2901-4IGN#PBF, the TOL pin directly controls undervoltage tolerance: a logic high selects 10% below nominal threshold (e.g., 4.500V for 5V rail), while a logic low selects 5% (e.g., 4.675V for 5V rail). This selection applies only to the LTC2901-3/LTC2901-4 variants and is confirmed in the Absolute Maximum Ratings table footnote 4.

Can LTC2901-4IGN#PBF monitor negative supply voltages?

Yes - the LTC2901-4IGN#PBF supports negative supply monitoring in –ADJ mode on V4. In this configuration, an external resistor divider connects between the negative rail and VREF (1.210V), with V4 tied to the divider tap. The internal comparator compares against VREF, enabling accurate trip-point setting for rails such as –5.2V or –12V as documented in Figure 6 and Table 3.

What is the minimum VCC required for reliable RST assertion on LTC2901-4IGN#PBF?

The LTC2901-4IGN#PBF guarantees correct RST logic state for VCC ≥ 1V, as specified in the Electrical Characteristics table under "VCC Minimum Internal Operating Voltage". This ensures valid reset behavior during brownout conditions and power-down sequences well before complete supply collapse.

How is watchdog timeout implemented on LTC2901-4IGN#PBF compared to LTC2901-2?

Unlike LTC2901-2 (which outputs watchdog status on a dedicated WDO pin), the LTC2901-4IGN#PBF merges watchdog timeout into the RST function: a missed WDI edge causes the RST pin to assert low for the programmed CRT delay period. This provides automatic full-system reset on software hang, eliminating need for external logic to combine WDO and RST signals.