Analog Devices Inc. LTC2908ITS8-A1#TRPBF

Overview

LTC2908ITS8-A1#TRPBF 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 5V, 3.3V, 2.5V, 1.8V, and two adjustable inputs (VADJ1/VADJ2) with ±1.5% threshold accuracy over –40°C to +85°C, 200ms reset timeout, and guaranteed RST low output down to VCC = 0.5V - used in network servers and optical networking systems.

For engineers reviewing the LTC2908ITS8-A1#TRPBF datasheet, LTC2908ITS8-A1#TRPBF pinout, LTC2908ITS8-A1#TRPBF application, or LTC2908ITS8-A1#TRPBF equivalent, key selection criteria include its dual adjustable input configuration, TSOT-23-8 package, –40°C to +85°C industrial temperature grade, open-drain RST output with internal 6μA pull-up, and compatibility with systems requiring simultaneous monitoring of legacy and custom rail voltages.

Technical Context

The LTC2908ITS8-A1#TRPBF implements six independent voltage comparators with bandgap reference and integrated 200ms reset timer. Its internal VCC auto-select logic uses the greater of V1 or V2 as supply, enabling operation even when one rail powers up first.

Glitch immunity is achieved via first-order low-pass filtering at each comparator output plus the 200ms timeout, rejecting transients >5Hz without hysteresis-induced threshold error. The RST output features strong active-low pull-down (≤0.15V @ 0.5V VCC) and weak internal pull-up (6μA to VCC), supporting wired-OR reset bus configurations.

Key Specifications

Pinout & Package

Package: 8-lead plastic TSOT-23 (ThinSOT™), 3mm × 1.75mm footprint, 1mm profile, RoHS-compliant lead-free finish.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6326UT46D3+ and TPS3808G12DBVR, the LTC2908ITS8-A1#TRPBF delivers integrated six-rail supervision with dual adjustable inputs and guaranteed sub-0.5V RST assertion - eliminating discrete component count, reducing PCB area, and enabling coordinated reset across heterogeneous voltage domains.

Availability

LTC2908ITS8-A1#TRPBF is available at Aetrix Electronics and suitable for network servers, wireless base stations, and optical networking systems requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for LTC2908ITS8-A1#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 LTC2908 product line delivers precision, low-power, multirail supply monitoring solutions targeting high-reliability infrastructure equipment where voltage margin, sequencing integrity, and brownout resilience are critical.

FAQ

What is the operating temperature range for the LTC2908ITS8-A1#TRPBF?

The LTC2908ITS8-A1#TRPBF is rated for industrial operation from –40°C to +85°C. This grade is confirmed by the "I" suffix in the part number and applies to all electrical specifications including ±1.5% threshold accuracy, 200ms reset timeout, and RST output behavior. The device maintains guaranteed RST low assertion down to VCC = 0.5V across this full range, making it suitable for base station outdoor cabinets and server chassis with elevated ambient temperatures.

How does the LTC2908ITS8-A1#TRPBF determine its internal supply voltage (VCC)?

The LTC2908ITS8-A1#TRPBF automatically selects VCC as the greater of the V1 and V2 input voltages. When V1 ≥ V2, V1 supplies the internal circuitry and draws ~26μA quiescent current; when V2 > V1, V2 becomes VCC and draws ~24μA. This auto-select feature ensures reliable operation regardless of power-up sequence order between the 5V and 3.3V rails, a critical requirement in complex multirail systems monitored by the LTC2908ITS8-A1#TRPBF.

Can unused inputs on the LTC2908ITS8-A1#TRPBF be left floating?

No, unused inputs on the LTC2908ITS8-A1#TRPBF must not be left floating. Per the datasheet, they should be tied to the closest higher available supply voltage (e.g., connect VADJ2 to 1.8V if only VADJ1 is used). Floating inputs risk noise coupling, comparator instability, and spurious reset assertion. The LTC2908ITS8-A1#TRPBF's internal architecture assumes defined DC states on all six inputs to maintain accurate threshold comparison and glitch immunity.

What is the purpose of the 0.5V reference on the VADJ inputs of the LTC2908ITS8-A1#TRPBF?

The 0.5V reference on VADJ1 and VADJ2 inputs of the LTC2908ITS8-A1#TRPBF serves as the comparator threshold for adjustable rails. By connecting an external resistor divider between the target rail and ground, with the tap point fed to VADJx, the trip voltage is set by VTRIP = 0.5V × (1 + R1/R2). This allows precise monitoring of nonstandard rails (e.g., 1.2V, 0.9V) using common 1% resistors - a key capability distinguishing the LTC2908ITS8-A1#TRPBF from fixed-threshold supervisors.

Does the LTC2908ITS8-A1#TRPBF require an external timing capacitor for its 200ms reset delay?

No, the LTC2908ITS8-A1#TRPBF does not require an external timing capacitor. Its 200ms reset timeout is generated by an internal capacitor and timer circuit, eliminating board space, cost, and reliability concerns associated with external components. This monolithic implementation ensures consistent timing across temperature and voltage, and is factory-trimmed to ±20% tolerance (160–260ms), as specified in the electrical characteristics table for the LTC2908ITS8-A1#TRPBF.