Analog Devices Inc. LTC2905CTS8#TRMPBF

Overview

LTC2905CTS8#TRMPBF from Analog Devices (formerly Linear Technology) is a precision dual supply monitor IC with pin-selectable thresholds and adjustable reset timeout. It monitors two independent voltage rails (e.g., 5V/3.3V, 3.3V/1.2V), provides ±1.5% threshold accuracy over temperature, supports 5%/7.5%/10% tolerance selection, and uses an external capacitor on the TMR pin to set reset delay (e.g., 200 ms with 22 nF). It is used in embedded power sequencing and fault detection for industrial microprocessor systems.

For engineers reviewing the LTC2905CTS8#TRMPBF datasheet, LTC2905CTS8#TRMPBF pinout, LTC2905CTS8#TRMPBF application, or LTC2905CTS8#TRMPBF equivalent, key selection criteria include its TSOT-23-8 package, open-drain RST output with guaranteed operation down to V_CC = 1 V, programmable dual-threshold architecture, glitch-immune timing, and compatibility with low-voltage I/O domains requiring precise brownout detection.

Technical Context

The LTC2905CTS8#TRMPBF implements a dual-comparator architecture with bandgap reference and three-state input decoding (S1, S2, TOL) to select one of nine V1/V2 threshold pairs and one of three tolerance levels. Its internal V_CC is auto-selected as the greater of V1 or V2, enabling self-powering from monitored rails.

Reset assertion is triggered when either input falls below its programmed threshold; recovery requires both inputs to exceed thresholds for the full TMR-programmed delay. The TMR pin accepts an external capacitor (9 ms/nF scaling) to set timeout from ~200 µs to >10 s, with no capacitor yielding minimum delay.

Key Specifications

Pinout & Package

Package: 8-Lead Plastic TSOT-23 (Thin Small Outline Transistor), 1.95 mm × 2.80 mm, 1.00 mm max height, lead-free finish. Pin 1 marked by bevelled edge.

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 LTC2905CTS8#TRMPBF uniquely delivers programmable dual-threshold selection, ±1.5% accuracy across temperature, and capacitor-adjustable reset timing - making it the only option supporting mixed-voltage systems (e.g., 5V + 1.2V) with production-ready margining and noise immunity.

Availability

LTC2905CTS8#TRMPBF is available at Aetrix Electronics and suitable for desktop computers, network servers, and industrial embedded controllers requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for LTC2905CTS8#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 acquired Linear Technology in 2017 and maintains its precision analog and power management portfolio. Linear pioneered high-accuracy voltage supervisors with integrated references and robust noise immunity.

The LTC2905CTS8#TRMPBF belongs to Linear's LTC290x dual-supply monitor family, designed specifically for space-constrained, multi-rail systems needing deterministic reset behavior without external passive components or firmware intervention.

FAQ

What is the function of the TMR pin on the LTC2905CTS8#TRMPBF?

The TMR pin on the LTC2905CTS8#TRMPBF is the reset timeout programming terminal. It accepts an external capacitor connected to GND to set the reset delay time (9 ms/nF scaling). For example, a 22 nF capacitor yields a nominal 200 ms delay. Leaving TMR open results in ~200 µs minimum delay. This pin replaces the fixed 200 ms delay found on the LTC2904CTS8#TRMPBF and is exclusive to LTC2905 variants.

Can the LTC2905CTS8#TRMPBF monitor a 5V and a 1.0V rail simultaneously?

Yes, the LTC2905CTS8#TRMPBF can monitor 5V and 1.0V rails simultaneously. Per Table 1 in the datasheet, setting S1 = V1 and S2 = GND selects V1 = 5.0V and V2 = 1.0V. The TOL pin then sets tolerance (5%/7.5%/10%), and the device guarantees RST assertion when either input falls below its programmed threshold, with internal V_CC derived from the higher rail (5V).

What is the minimum supply voltage required for the LTC2905CTS8#TRMPBF to assert a valid RST signal?

The LTC2905CTS8#TRMPBF guarantees correct RST logic state (low output) for V1 ≥ 1 V or V2 ≥ 1 V. Since internal V_CC equals the greater of V1 or V2, the device remains fully functional and asserts RST reliably down to 1 V on either monitored rail - a critical feature for brownout detection in low-voltage systems.

How does the LTC2905CTS8#TRMPBF achieve ±1.5% threshold accuracy without external calibration?

The LTC2905CTS8#TRMPBF achieves ±1.5% threshold accuracy using a trimmed bandgap reference and laser-trimmed resistor network inside the IC. This trimming occurs during wafer test and is retained across temperature (0°C to 70°C for the C-grade LTC2905CTS8#TRMPBF), eliminating need for external calibration or system-level compensation.

Is the LTC2905CTS8#TRMPBF pin-compatible with the LTC2904CTS8#TRMPBF?

No, the LTC2905CTS8#TRMPBF is not pin-compatible with the LTC2904CTS8#TRMPBF. Although both use the TSOT-23-8 package, Pin 2 is RST (output) on the LTC2904CTS8#TRMPBF but TMR (capacitor input) on the LTC2905CTS8#TRMPBF, and Pin 3 is inverted RST on both. Swapping them causes functional failure - the LTC2905CTS8#TRMPBF requires external timing capacitance, while the LTC2904CTS8#TRMPBF has fixed internal delay.