Analog Devices Inc. LTC2900-2IDD#TRPBF

Overview

LTC2900-2IDD#TRPBF from Analog Devices (formerly Linear Technology) is a programmable quad supply monitor IC with push-pull RST output, simultaneously monitoring up to four voltage rails (e.g., 5V, 3.3V, 2.5V, 1.8V), ±1.5% threshold accuracy over temperature, 43µA typical supply current, and adjustable reset timeout via external capacitor. It is used in multivoltage embedded systems requiring reliable power-on reset and brownout detection.

For engineers reviewing the LTC2900-2IDD#TRPBF datasheet, LTC2900-2IDD#TRPBF pinout, LTC2900-2IDD#TRPBF application, or LTC2900-2IDD#TRPBF equivalent, key selection factors include its push-pull RST output (vs open-drain), guaranteed RST validity down to VCC = 1V, 10-lead 3mm × 3mm DFN package, and support for ±adjustable thresholds on V3/V4 inputs.

Technical Context

The LTC2900-2IDD#TRPBF implements four independent high-accuracy comparators referenced to a buffered 1.210V internal bandgap, with threshold selection via a resistor divider on VPG. Its architecture guarantees correct RST state for VCC ≥ 1V and provides glitch immunity during supply transients.

Reset timing is externally programmable via CRT pin capacitance (tRST ≈ 217 pF/ms), and manual reset is supported via PBR with internal pull-up. The push-pull RST output actively drives high to V2 (not open-drain), enabling direct CMOS interfacing without external pull-up resistors.

Key Specifications

Pinout & Package

Package: 10-lead 3mm × 3mm plastic DFN (exposed pad), RoHS-compliant, θJA = 43°C/W.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LTC2901CMS#PBF and LTC2902IMS#PBF, the LTC2900-2IDD#TRPBF delivers essential quad monitoring in the smallest footprint (3mm × 3mm DFN) with lowest quiescent current (43µA), making it ideal for space- and power-constrained designs where watchdog or margining features are unnecessary.

Availability

LTC2900-2IDD#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 RoHS-compliant packaging.

Supply support for LTC2900-2IDD#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 full product support, documentation, and manufacturing continuity for the LTC portfolio.

The LTC2900 family was designed specifically for high-accuracy, low-power quad supply monitoring in multirail systems, emphasizing threshold stability, glitch immunity, and flexible rail configuration without external components.

FAQ

What is the function of the CRT pin on the LTC2900-2IDD#TRPBF?

The CRT pin on the LTC2900-2IDD#TRPBF sets the reset timeout period by connecting an external capacitor to ground. With CRT = 47nF, the LTC2900-2IDD#TRPBF generates a 216ms reset pulse; the relationship is tRST ≈ 4.6ms/nF. Leaving CRT unconnected yields ~50µs minimum delay. This allows precise adaptation to processor power-up timing requirements without firmware changes.

How does the push-pull RST output of the LTC2900-2IDD#TRPBF differ from the open-drain version?

The LTC2900-2IDD#TRPBF features a push-pull RST output that actively drives high to V2 (not just weak pull-up), enabling faster rise times (~206ns with 150pF load) and eliminating the need for external pull-up resistors. In contrast, the LTC2900-1 variant uses open-drain RST with only weak internal pull-up (~6µA), requiring external components for reliable CMOS interfacing. This makes the LTC2900-2IDD#TRPBF simpler to integrate in high-speed digital systems.

Can the LTC2900-2IDD#TRPBF monitor negative supply voltages?

Yes - the LTC2900-2IDD#TRPBF supports negative supply monitoring on V4 using the –ADJ mode. In this configuration, V4 connects to a resistive divider between the negative rail and VREF (1.210V), enabling accurate trip-point setting (e.g., –4.64V). The internal comparator offset and VREF level-shift ensure correct operation without external op-amps or level translators, confirmed in the datasheet's Figure 6 and Table 3.

What is the minimum VCC required for the LTC2900-2IDD#TRPBF to guarantee correct RST logic state?

The LTC2900-2IDD#TRPBF guarantees correct RST logic state for VCC ≥ 1V, as specified in the Absolute Maximum Ratings table. This means RST remains asserted (low) during brownout until VCC rises above 1V, then transitions correctly after all monitored rails exceed their thresholds and the programmed delay expires. This specification is validated across the full –40°C to 85°C operating range and is critical for fail-safe operation in power-constrained systems.

How is voltage threshold selection implemented on the LTC2900-2IDD#TRPBF?

Threshold selection on the LTC2900-2IDD#TRPBF is performed via a resistor divider connected between VREF and GND, with the tap point applied to the VPG pin. The VPG voltage determines one of 16 preset combinations (e.g., 5V/3.3V/2.5V/1.8V) or ±adjustable modes. Table 1 in the datasheet lists exact 1% resistor values (e.g., R1 = 59.0kΩ, R2 = 40.2kΩ for 5V/3.3V/2.5V/1.8V), and the LTC2900-2IDD#TRPBF samples VPG during a 150µs window after VCC reaches 2.4V.