Analog Devices Inc. LTC2908ITS8-B1#TRM

Overview

LTC2908ITS8-B1#TRM from Analog Devices (formerly Linear Technology) is a precision six-input supply monitor IC designed for multivoltage systems requiring tight threshold accuracy and ultralow-voltage reset assertion. It monitors 3.3V, 2.5V, 1.8V, 1.5V, and two adjustable inputs (VADJ1/VADJ2) with ±1.5% threshold accuracy over temperature, 200ms reset timeout, and guaranteed RST pull-down operation down to VCC = 0.5V - enabling reliable power sequencing in network servers and optical networking equipment.

For engineers reviewing the LTC2908ITS8-B1#TRM datasheet, LTC2908ITS8-B1#TRM pinout, LTC2908ITS8-B1#TRM application, or LTC2908ITS8-B1#TRM equivalent, key selection considerations include its B1-specific voltage thresholds (3.3V/2.5V/1.8V/1.5V), TSOT-23-8 package, –40°C to 85°C industrial temperature grade, open-drain RST output with internal 6μA pull-up, and dual adjustable input capability for custom trip points.

Technical Context

The LTC2908ITS8-B1#TRM implements six independent comparators referenced to a bandgap-derived 0.5V internal reference, with each comparator feeding a glitch-immune timing circuit that enforces a 200ms delay before releasing RST. Its internal VCC auto-select logic uses the greater of V1 or V2 as the supply rail, enabling operation even when only one monitored rail is active above 0.5V.

Thresholds are fixed for V1–V4 (3.3V, 2.5V, 1.8V, 1.5V) and adjustable via external resistor dividers on VADJ1/VADJ2, both referenced to the same 0.5V comparator input. The RST output is actively pulled low during fault conditions and weakly pulled high to VCC after all inputs remain valid for ≥200ms - supporting wired-OR reset bus configurations across multiple supervisors.

Key Specifications

Pinout & Package

Package: 8-lead plastic TSOT-23 (ThinSOT™), 1mm profile, footprint compatible with standard SOT-23 land pattern. Exposed pad not present in TSOT-23 variant (only DFN DDB8 has exposed pad).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6326US33D3+T and TPS3808G33DBVR, the LTC2908ITS8-B1#TRM delivers integrated six-rail supervision in one TSOT-23 package with ±1.5% accuracy and ultralow-voltage reset - eliminating layout complexity, reducing component count, and enabling robust multivoltage system reliability unattainable with single-input alternatives.

Availability

LTC2908ITS8-B1#TRM is available at Aetrix Electronics and suitable for network servers, optical networking systems, and multivoltage industrial controllers requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for LTC2908ITS8-B1#TRM 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 for precision instrumentation, communications, and industrial applications.

The LTC2908 product line delivers compact, high-accuracy power supply supervisors targeting multivoltage systems in telecom infrastructure, computing, and industrial automation - emphasizing threshold precision, low-voltage operation, and noise immunity.

FAQ

What voltage rails does the LTC2908ITS8-B1#TRM monitor by default?

The LTC2908ITS8-B1#TRM monitors four fixed rails - V1=3.3V, V2=2.5V, V3=1.8V, V4=1.5V - plus two adjustable inputs (VADJ1/VADJ2) referenced to an internal 0.5V comparator threshold. This B1 variant is specifically configured for 3.3V/2.5V/1.8V/1.5V systems, unlike A1 (5V/3.3V/2.5V/1.8V) or C1 (2.5V + five adjustable inputs). Each threshold maintains ±1.5% accuracy over –40°C to +85°C.

How does the LTC2908ITS8-B1#TRM handle power-up sequencing?

During power-up, the LTC2908ITS8-B1#TRM asserts RST low as soon as V1 or V2 reaches 0.5V, then holds RST low until all six inputs exceed their respective thresholds for a continuous 200ms period. The internal VCC auto-select uses the higher of V1/V2 to power the circuitry, ensuring reliable operation even if only one rail powers up first - critical for staggered supply architectures in servers and base stations.

Can multiple LTC2908ITS8-B1#TRM devices share a common reset line?

Yes - the LTC2908ITS8-B1#TRM features an open-drain RST output, enabling wired-OR connection of multiple devices to a single system reset bus. When any LTC2908ITS8-B1#TRM detects a fault, its RST pulls low, forcing the shared line low regardless of other devices' states. This allows scalable monitoring of >6 rails without external logic, provided external pull-up resistance is sized for total sink current.

What is the minimum supply voltage required for the LTC2908ITS8-B1#TRM to assert a valid reset?

The LTC2908ITS8-B1#TRM guarantees RST output low with VCC ≥ 0.5V (where VCC = max(V1,V2)), achieving VOL ≤ 0.15V at IRST = 5μA. This ultralow-voltage capability ensures deterministic reset assertion during deep brownout conditions where other supervisors fail - validated across the full –40°C to +85°C temperature range per datasheet specifications.

How do I configure the adjustable inputs (VADJ1/VADJ2) on the LTC2908ITS8-B1#TRM?

Connect each VADJ pin to a resistor divider between the target supply and ground, with the divider's tap at VADJ and the bottom resistor (R2) fixed at 100kΩ. Use R1 = (VTRIP / 0.5V − 1) × R2 to set trip voltage (e.g., 12V → R1 = 2150kΩ). The LTC2908ITS8-B1#TRM's 0.5V reference and <15nA input bias enable precise, low-loading adjustment - verified in Table 1 of the official datasheet for 1% resistor values.