Analog Devices Inc. LTC2905ITS8#TRMPBF

Overview

LTC2905ITS8#TRMPBF from Analog Devices (formerly Linear Technology) is a precision dual supply voltage monitor IC with pin-selectable thresholds and adjustable reset timeout. It monitors two independent supply rails (e.g., 5V/3.3V, 3.3V/1.2V), delivers ±1.5% threshold accuracy over –40°C to +85°C, supports 5%/7.5%/10% tolerance selection via three-state inputs, and uses an external capacitor on the TMR pin to set reset delay (e.g., 200 ms with 22 nF). It is deployed in embedded power sequencing for industrial controllers and telecom infrastructure.

For engineers reviewing the LTC2905ITS8#TRMPBF datasheet, LTC2905ITS8#TRMPBF pinout, LTC2905ITS8#TRMPBF application, or LTC2905ITS8#TRMPBF equivalent, key selection criteria include its adjustable reset timeout capability, guaranteed RST operation down to V1 ≥ 1 V or V2 ≥ 1 V, open-drain RST output with internal weak pull-up, 8-pin TSOT-23 package footprint, and support for nine distinct voltage threshold combinations without external resistors.

Technical Context

The LTC2905ITS8#TRMPBF implements dual high-accuracy comparators with a shared bandgap reference and resistor network, enabling precise undervoltage detection on V1 and V2 simultaneously. Its three-state programming pins (S1, S2, TOL) configure both nominal thresholds and common tolerance without trimming components.

Reset assertion is synchronized to the higher of V1/V2 (which becomes internal VCC), ensuring reliable operation during power-up when either rail reaches 1 V. The TMR pin accepts an external capacitor to set the reset timeout period (tRST = 9 ms/nF), providing design flexibility unmatched by fixed-delay alternatives like the LTC2904.

Key Specifications

Pinout & Package

Package: 8-lead Plastic TSOT-23 (0.65 mm pitch), 1.95 mm × 2.80 mm body, 0.8–0.9 mm height, exposed pad not present (unlike DFN variant).

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS3808G33DBVR and MAX6816EUT+T, the LTC2905ITS8#TRMPBF uniquely supports nine asymmetric voltage combinations, capacitor-adjustable reset timing, and guaranteed operation down to 1 V - making it the only option for space-constrained, multi-rail systems requiring precision and configurability.

Availability

LTC2905ITS8#TRMPBF is available at Aetrix Electronics and suitable for industrial PLC power sequencing, telecom line card supervision, medical imaging sensor modules, and automotive ADAS camera ECUs requiring stable component supply across extended temperature ranges.

Supply support for LTC2905ITS8#TRMPBF 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 LTC2905ITS8#TRMPBF belongs to the Linear Technology LTC® precision supervisor family, designed specifically for high-accuracy, low-power dual-supply monitoring in space- and reliability-critical embedded systems.

FAQ

What is the maximum reset timeout achievable with LTC2905ITS8#TRMPBF?

The LTC2905ITS8#TRMPBF reset timeout (tRST) scales linearly with the TMR capacitor value: tRST = 9 ms/nF. With a 100 nF capacitor, tRST ≈ 900 ms. Larger capacitors (e.g., 1 μF) yield ~9 s, but leakage current must remain below 2.1 μA to prevent premature discharge. The LTC2905ITS8#TRMPBF datasheet confirms no upper limit beyond capacitor availability and leakage constraints.

Can LTC2905ITS8#TRMPBF monitor 5V and 1.0V supplies simultaneously?

Yes. Per Table 1 in the LTC2905ITS8#TRMPBF datasheet, setting S1 = V1 and S2 = GND configures V1 = 5.0 V and V2 = 1.0 V. The device then monitors both rails against their respective thresholds (e.g., 4.75 V ±1.5% for V1, 0.95 V ±1.5% for V2), asserting RST if either falls below its programmed level. This pairing is explicitly supported.

Does LTC2905ITS8#TRMPBF require external pull-up resistors on the RST pin?

No external pull-up is required for basic operation: the LTC2905ITS8#TRMPBF integrates a ~6 μA weak pull-up to VCC (the higher of V1/V2). However, if faster rise time (<10 μs) or VOH > VCC is needed, a 10 kΩ external pull-up to a higher voltage rail is recommended - as confirmed in the LTC2905ITS8#TRMPBF Typical Performance Characteristics (Figure G15).

How does LTC2905ITS8#TRMPBF handle supply noise near threshold voltage?

The LTC2905ITS8#TRMPBF combats noise via two mechanisms: (1) a first-order low-pass filter at each comparator output to reject short transients, and (2) the programmable tRST delay, which ignores noise events shorter than 1/tRST. Together, they prevent false resets without adding hysteresis-induced threshold error - a key advantage documented in the LTC2905ITS8#TRMPBF Applications Information section.

What is the minimum supply voltage required for LTC2905ITS8#TRMPBF to guarantee correct RST logic state?

The LTC2905ITS8#TRMPBF guarantees correct RST logic state when V1 ≥ 1 V or V2 ≥ 1 V, as specified in the Absolute Maximum Ratings and Electrical Characteristics tables. At this level, the internal circuitry remains functional and RST will assert low if either input falls below its threshold. This 1 V minimum enables reliable brownout detection in low-voltage systems.