Analog Devices Inc. LTC2908IDDB-C1#TRPBF

Overview

LTC2908IDDB-C1#TRPBF from Analog Devices (formerly Linear Technology) is a precision six-input supply voltage supervisor IC designed for multivoltage systems requiring tight threshold accuracy and ultralow-voltage reset assertion. It monitors V1 plus five adjustable inputs (VADJ1–VADJ5) with ±1.5% threshold accuracy over temperature, features a 200ms reset timeout, and guarantees RST pull-down operation down to VCC = 0.5V. It is used in optical networking systems and desktop computers for reliable power-on reset and brownout detection.

For engineers reviewing the LTC2908IDDB-C1#TRPBF datasheet, LTC2908IDDB-C1#TRPBF pinout, LTC2908IDDB-C1#TRPBF application, or LTC2908IDDB-C1#TRPBF equivalent, key selection criteria include its 2.5V nominal internal supply (V1 only), 0.5V adjustable input threshold, 8-lead DFN package, open-drain RST output with guaranteed low-state behavior at 0.5V, and compatibility with systems requiring simultaneous monitoring of five adjustable rails plus one fixed rail.

Technical Context

The LTC2908IDDB-C1#TRPBF implements six independent comparators referenced to a bandgap-derived 0.5V internal reference, each driving a glitch-immune timing circuit. Its architecture uses internal auto-select of V1 as the sole internal supply (VCC), eliminating dependency on V2–V4 - unlike A1/B1 variants - simplifying biasing in 2.5V-centric systems.

All six inputs are configured as adjustable (VADJ1–VADJ5 + V1), with identical 0.492V to 0.508V threshold range (±1.5%) across –40°C to +85°C. The 200ms reset timeout is generated by an internal capacitor, requiring no external timing components, and the RST output remains asserted low until all six inputs exceed their thresholds for the full delay period.

Key Specifications

Pinout & Package

Package: 8-lead (3mm × 2mm) plastic DFN (DDB8), 1mm profile, exposed pad (Pin 9, optional GND connection).

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS3808G33DBVR and MAX6816EUT+T, the LTC2908IDDB-C1#TRPBF uniquely delivers six fully adjustable inputs with ±1.5% accuracy and guaranteed 0.5V RST operation - making it the only option for high-density, precision multirail systems demanding minimal voltage margin and deterministic low-voltage reset behavior.

Availability

LTC2908IDDB-C1#TRPBF is available at Aetrix Electronics and suitable for optical networking systems, desktop computers, and network servers requiring stable component supply, long-term lifecycle support, and guaranteed industrial temperature range (–40°C to +85°C) performance.

Supply support for LTC2908IDDB-C1#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 was designed specifically for precision multivoltage system supervision - targeting telecom infrastructure, computing, and industrial equipment where reliability, accuracy, and space efficiency are critical.

FAQ

What is the internal supply configuration of the LTC2908IDDB-C1#TRPBF?

The LTC2908IDDB-C1#TRPBF uses V1 exclusively as its internal supply (VCC); unlike A1/B1 variants, it does not use V2 as an alternate VCC source. This simplifies biasing in 2.5V-centric designs and eliminates ambiguity in power-source selection. V1 must be ≥0.5V to guarantee correct RST logic state, and it powers all internal comparators, reference, and timing circuitry in the LTC2908IDDB-C1#TRPBF.

How do I configure the adjustable inputs (VADJ1–VADJ5) on the LTC2908IDDB-C1#TRPBF?

Each VADJ pin connects to the inverting input of a comparator referenced to an internal 0.5V bandgap. To set a trip voltage (VTRIP), use a resistor divider between the supply rail and GND, with the tap connected to the VADJ pin. With R2 = 100kΩ (recommended), R1 = (VTRIP / 0.5V − 1) × R2. For example, to monitor 3.3V, R1 = (3.3 / 0.5 − 1) × 100kΩ = 560kΩ. All five VADJ inputs on the LTC2908IDDB-C1#TRPBF share identical ±1.5% threshold accuracy and ±15nA input bias current.

Does the LTC2908IDDB-C1#TRPBF require external timing components for its 200ms reset delay?

No, the LTC2908IDDB-C1#TRPBF integrates the 200ms reset timeout capacitor internally. This eliminates the need for external timing resistors or capacitors, reducing BOM count, PCB area, and layout sensitivity. The timeout is factory-trimmed to 200ms (160–260ms over temperature), and no user adjustment is possible - a key differentiator from programmable supervisors. This internal timing is active in all operating modes of the LTC2908IDDB-C1#TRPBF.

What is the minimum supply voltage required for the RST output to function correctly in the LTC2908IDDB-C1#TRPBF?

The LTC2908IDDB-C1#TRPBF guarantees correct RST logic state (low output ≤ 0.15V) with V1 ≥ 0.5V. Below 0.5V, RST behavior is undefined. This ultralow-voltage capability ensures deterministic reset assertion during deep brownout - a critical feature absent in most competing supervisors. The RST pull-down strength degrades gradually above 0.5V but remains functional up to 6V, and the weak internal pull-up tracks V1 directly in the LTC2908IDDB-C1#TRPBF.

Can multiple LTC2908IDDB-C1#TRPBF devices be connected in parallel for more than six supply rails?

Yes, the open-drain RST outputs of multiple LTC2908IDDB-C1#TRPBF devices can be wired-OR together on a common reset bus. When any device asserts RST low, the entire bus is pulled low - providing system-level reset if any rail fails across any subset of monitored domains. No additional logic or diodes are needed. This scalability is explicitly supported in the LTC2908IDDB-C1#TRPBF datasheet and leverages its guaranteed low-state behavior even at 0.5V V1.