Analog Devices Inc. LTC2902-1IGN#PBF

Overview

LTC2902-1IGN#PBF from Analog Devices (formerly Linear Technology) is a programmable quad supply monitor IC with open-drain RST output, designed for reliable power-on reset and brownout detection in multivoltage systems. It simultaneously monitors four supplies (e.g., 5V, 3.3V, 2.5V, 1.8V) with ±1.5% threshold accuracy over temperature, selectable 5–12.5% supply tolerance, adjustable reset delay via external capacitor, and guaranteed RST assertion down to VCC = 1V. Used in telecom equipment and network servers requiring precise, glitch-immune supply supervision.

For engineers reviewing the LTC2902-1IGN#PBF datasheet, LTC2902-1IGN#PBF pinout, LTC2902-1IGN#PBF application, or LTC2902-1IGN#PBF equivalent, key selection criteria include its 16-lead SSOP package, open-drain RST output (distinguishing it from push-pull LTC2902-2 variants), programmable voltage combinations via VPG resistor divider, individual nondelayed COMP outputs per supply, and low 43µA quiescent current for power-sensitive designs.

Technical Context

The LTC2902-1IGN#PBF implements four independent high-accuracy voltage comparators referenced to a buffered 1.210V internal bandgap, with thresholds set by external resistor dividers on VPG and scaled by T0/T1 digital inputs for 5%, 7.5%, 10%, or 12.5% tolerance modes. Its architecture guarantees correct RST logic state for VCC ≥ 1V and includes dedicated RDIS input for margin testing without reset assertion.

Reset timing is controlled by an external capacitor on CRT pin (4.6ms/nF scaling), while each comparator output (COMP1–COMP4) provides active-high, nondelayed status with weak internal pull-up to V2. The device supports both positive adjustable (ADJ) and negative adjustable (–ADJ) monitoring modes on V3/V4, enabling flexible sensing of 1.5V–12V and –2V to –12V rails using ratiometric dividers referenced to VREF or ground.

Key Specifications

Pinout & Package

Package: 16-lead plastic SSOP (narrow, 0.150" width), JEDEC MS-013AC compliant, RoHS-compliant lead finish.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LTC2902-2IGN#PBF, the LTC2902-1IGN#PBF provides open-drain RST for multi-drop bus compatibility and level translation, while LTC1326-2.5 lacks quad monitoring, programmability, and adjustable reset timing - making it unsuitable for complex multivoltage systems requiring full configurability.

Availability

LTC2902-1IGN#PBF is available at Aetrix Electronics and suitable for desktop computers, telecom equipment, and network servers requiring stable component supply, long-term lifecycle support, and consistent parametric performance across production batches.

Supply support for LTC2902-1IGN#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. (acquired Linear Technology in 2017) is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving industrial, automotive, communications, and healthcare markets.

The LTC2902 product line delivers precision, programmable power supply supervision ICs targeting multivoltage systems where reliability, accuracy, and design flexibility are critical - especially in telecom infrastructure and enterprise computing.

FAQ

What is the function of the RDIS pin on the LTC2902-1IGN#PBF?

The RDIS (Reset Disable) pin on the LTC2902-1IGN#PBF is an active-low digital input that forces the RST output high regardless of monitored supply conditions. When pulled low, it overrides all reset assertions, allowing engineers to perform supply margin testing under processor control without triggering a system reset. The pin features a weak internal 10µA pull-up, so it may be left floating for normal operation. This functionality is integral to the LTC2902-1IGN#PBF's role in validation workflows.

How does the CRT capacitor determine reset delay time for the LTC2902-1IGN#PBF?

The CRT capacitor connected between Pin 5 (CRT) and GND sets the reset timeout period for the LTC2902-1IGN#PBF using a linear 4.6ms/nF scaling factor - for example, a 47nF capacitor yields ~216ms delay. Leaving CRT unconnected results in a minimum delay of ~50µs. Capacitor leakage and tolerance directly affect timing accuracy, so low-leakage ceramic types are recommended. This external timing element gives designers full control over reset duration without firmware involvement, a core capability of the LTC2902-1IGN#PBF.

What voltage combinations can be programmed on the LTC2902-1IGN#PBF using the VPG pin?

The LTC2902-1IGN#PBF supports 16 distinct voltage-monitor combinations selected by applying a precise voltage ratio (0–1.0 × VREF) to the VPG pin via an external 1% resistor divider. Valid configurations include 5V/3.3V/ADJ/ADJ, 5V/3.3V/2.5V/1.8V, 3.3V/2.5V/1.8V/1.5V, and negative adjustable modes (e.g., 5V/3.3V/ADJ/–ADJ). Table 1 in the official datasheet specifies exact resistor values and VPG/VREF ratios for each mode, ensuring accurate setup of the LTC2902-1IGN#PBF for target rail voltages.

Why does the LTC2902-1IGN#PBF specify different minimum operating voltages for programming versus comparator operation?

The LTC2902-1IGN#PBF requires VCC ≥ 2.42V (VCCMINP) to enter programming mode during power-up, ensuring reliable sampling of the VPG voltage within the 150µs window. Once programmed, comparators remain functional down to VCC = 2.32V (VCCMINC), and RST/COMP outputs are guaranteed correct down to VCC = 1V. This staged voltage dependency allows the LTC2902-1IGN#PBF to initialize correctly at higher voltage while maintaining supervisory function through deeper brownout - a key reliability feature for mission-critical systems.

How does the LTC2902-1IGN#PBF achieve ±1.5% threshold accuracy over temperature?

The LTC2902-1IGN#PBF achieves ±1.5% threshold accuracy over temperature through a trimmed, curvature-corrected bandgap reference (VREF = 1.210V ±1.5%) and matched comparator input stages with low offset drift. All voltage thresholds are derived from this stable reference and scaled digitally via T0/T1 inputs - eliminating resistor-tolerance dependence in the signal path. This design ensures the LTC2902-1IGN#PBF maintains tight trip-point consistency from –40°C to 85°C without external calibration.