Analog Devices Inc. LTC2902-1IGN#TRPBF

Overview

LTC2902-1IGN#TRPBF from Analog Devices (formerly Linear Technology) is a programmable quad supply monitor IC with open-drain RST output, designed for multivoltage system power integrity supervision. 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, and adjustable reset delay via external capacitor. Used in telecom equipment and network servers to ensure reliable power-up sequencing and brownout protection.

For engineers reviewing the LTC2902-1IGN#TRPBF datasheet, LTC2902-1IGN#TRPBF pinout, LTC2902-1IGN#TRPBF application, or LTC2902-1IGN#TRPBF equivalent, key selection criteria include guaranteed RST assertion down to VCC = 1V, individual nondelayed comparator outputs per supply, low 43µA quiescent current, and compatibility with margining via RDIS pin.

Technical Context

The LTC2902-1IGN#TRPBF implements four independent voltage comparators referenced to a buffered 1.210V internal bandgap, with thresholds set via resistor divider on VPG and digitally scaled tolerance selection via T0/T1 pins. Its architecture guarantees glitch immunity and correct RST logic state across VCC ≥ 1V, enabling robust operation during slow-ramp or asymmetric power-up.

Reset timing is externally programmable using CRT pin capacitance (4.6ms/nF), while each COMPX output provides immediate undervoltage indication without delay. The open-drain RST output (LTC2902-1 variant) supports flexible pull-up configurations up to 7V, and all logic outputs are weakly pulled to V2 - the higher of V1 or V2 - which serves as the internal supply rail.

Key Specifications

Pinout & Package

Package: 16-lead plastic SSOP (narrow, 0.150" body width), JEDEC MO-137AC compliant, thermal resistance θJA = 130°C/W.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LTC2902-2IGN#TRPBF, the LTC2902-1IGN#TRPBF offers greater interface flexibility via open-drain RST but requires an external pull-up; versus LTC1326CMS8#TRPBF, it provides full quad monitoring, programmability, and tolerance adjustment at the expense of slightly lower threshold accuracy.

Availability

LTC2902-1IGN#TRPBF is available at Aetrix Electronics and suitable for desktop computers, telecom equipment, and network servers requiring stable component supply, long-term lifecycle support, and guaranteed performance across industrial temperature ranges (–40°C to +85°C).

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

The LTC2902 product line delivers precision, low-power, programmable power supply supervisors for multivoltage systems in computing, communications, and industrial applications - emphasizing configurability, reliability, and ease of integration.

FAQ

What is the function of the CRT pin on the LTC2902-1IGN#TRPBF?

The CRT pin on the LTC2902-1IGN#TRPBF sets the reset timeout period by connecting an external capacitor to ground. The relationship is linear: tRST = 4.6ms per nanofarad. A 47nF capacitor yields ~216ms delay. Leaving CRT unconnected results in ~50µs minimum delay. Capacitor leakage directly impacts timing accuracy, so low-leakage ceramic types are recommended for the LTC2902-1IGN#TRPBF.

How does the RDIS pin affect reset behavior in the LTC2902-1IGN#TRPBF?

The RDIS pin on the LTC2902-1IGN#TRPBF is an active-low control that forces the RST output high regardless of supply conditions. When pulled low, it overrides all comparator decisions and disables reset assertion - enabling safe supply margin testing under processor control. An internal 10µA pull-up allows RDIS to float for normal operation, making the LTC2902-1IGN#TRPBF ideal for validation workflows requiring intentional undervoltage stress without system reboot.

Can the LTC2902-1IGN#TRPBF monitor negative supply voltages?

Yes, the LTC2902-1IGN#TRPBF supports negative supply monitoring via its –ADJ mode on the V4 input. In this configuration, V4 connects to a resistive divider between the negative rail and VREF (1.210V), leveraging VREF as a level-shift reference. The trip voltage is calculated as VTRIP = VREF × (R3/R4). For example, a –5V rail with R3 = 464kΩ and R4 = 121kΩ yields VTRIP ≈ –4.64V. This capability is explicitly documented for the LTC2902-1IGN#TRPBF in the –ADJ section of the datasheet.

What is the role of the VPG pin in configuring the LTC2902-1IGN#TRPBF?

The VPG pin on the LTC2902-1IGN#TRPBF selects one of 16 predefined voltage threshold combinations (e.g., 5V/3.3V/2.5V/1.8V or mixed ADJ/–ADJ modes) via a resistor divider from VREF to GND. During a ~150µs programming window after VCC reaches 2.4V, the part samples VPG voltage and configures internal comparators accordingly. Table 1 in the LTC2902-1IGN#TRPBF datasheet specifies exact resistor values (e.g., R1 = 59.0kΩ, R2 = 40.2kΩ for 5V/3.3V/2.5V/1.8V mode) and mandates no added capacitance on VPG to ensure reliable programming.

How does the LTC2902-1IGN#TRPBF ensure reliable reset assertion during brownout conditions?

The LTC2902-1IGN#TRPBF guarantees correct RST logic state down to VCC = 1V, meaning it asserts reset reliably even as supplies collapse. Its internal circuitry remains functional and comparators retain accuracy until VCC drops below this threshold. Additionally, power-up behavior ensures RST stays low until all monitored rails exceed their thresholds and the programmed delay expires - preventing premature release. This VCC = 1V guarantee is a specified parameter in the LTC2902-1IGN#TRPBF Electrical Characteristics table and is critical for brownout resilience.