Analog Devices Inc. LTC2911IDDB-5

Overview

LTC2911IDDB-5 from Analog Devices (formerly Linear Technology) is a precision triple supply monitor IC with integrated power-fail comparator and latched reset control. It monitors a fixed 3.3V supply on V1, an adjustable supply on V2 (0.5V threshold), and a second adjustable input on ADJ (0.5V threshold), all with ±1.5% threshold accuracy over –40°C to 85°C. Its RST output asserts low on undervoltage, PFO signals early power-fail warning, and TMR enables latch mode for margin testing - used in industrial embedded systems requiring reliable multi-rail supervision.

For engineers reviewing the LTC2911IDDB-5 datasheet, LTC2911IDDB-5 pinout, LTC2911IDDB-5 application, or LTC2911IDDB-5 equivalent, key selection criteria include its 3.3V/ADJ/ADJ monitoring configuration, 200ms internal reset timeout, 30µA quiescent current, 0.5V comparator thresholds, and DFN-8 (3mm × 2mm) package with exposed pad - critical for space-constrained, low-power, high-accuracy power sequencing and fault detection.

Technical Context

The LTC2911IDDB-5 implements three independent voltage comparators: one fixed 3.3V monitor (V1), one high-impedance adjustable input (V2) with 0.5V nominal threshold, and a second adjustable input (ADJ) also at 0.5V. All comparators feature ±1.5% threshold accuracy across temperature and built-in glitch filtering for noise immunity.

Its power-fail function uses the PFI input (500mV falling / 515mV rising threshold) to drive PFO low for early warning; the TMR pin supports three modes - external capacitor timeout, internal 200ms timeout (TMR = V1), or latch mode (TMR = GND) - enabling flexible reset timing and margin testing without system reset interference.

Key Specifications

Pinout & Package

Package: 8-lead (3mm × 2mm) plastic DFN with exposed pad (pin 9, optional GND connection). Thermal resistance θ_JA = 76°C/W enables reliable operation at full rated load in compact layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6369KA+T and TPS3808G33DBVR, the LTC2911IDDB-5 uniquely integrates triple adjustable monitoring, dedicated PFI-based early warning, and TMR latch mode - making it the only option among the three capable of full-system power integrity assurance in space-constrained industrial designs.

Availability

LTC2911IDDB-5 is available at Aetrix Electronics and suitable for industrial automation, automotive body electronics, medical device power management, and network infrastructure requiring stable component supply, long-term lifecycle support, and guaranteed parametric performance.

Supply support for LTC2911IDDB-5 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. (ADI) is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving industrial, automotive, communications, and healthcare markets.

The LTC2911 family was designed by Linear Technology (acquired by ADI in 2017) specifically for high-accuracy, low-power multi-rail power supervision in mission-critical embedded systems - emphasizing threshold stability, glitch immunity, and flexible reset timing.

FAQ

What is the exact monitoring configuration of the LTC2911IDDB-5?

The LTC2911IDDB-5 is the -5 variant of the LTC2911 family, configured to monitor a fixed 3.3V supply on V1, an adjustable supply on V2 (0.5V threshold), and a second adjustable supply on ADJ (0.5V threshold). This differs from -1 through -4 variants that fix V2 to 5V, 2.5V, 1.8V, or 1.2V. The LTC2911IDDB-5 enables full flexibility for dual adjustable rail supervision alongside the mandatory 3.3V rail.

How does the LTC2911IDDB-5 achieve its 200ms reset timeout without an external capacitor?

The LTC2911IDDB-5 achieves its 200ms reset timeout by tying the TMR pin to V1, which activates the internal timer circuit. This eliminates the need for an external timing capacitor, reducing component count and PCB area. The internal timeout is specified as 140ms to 280ms over temperature, with 200ms typical - matching the performance of externally timed variants while improving reliability and layout simplicity.

Can the LTC2911IDDB-5 monitor supplies lower than 0.5V?

No, the LTC2911IDDB-5 cannot directly monitor supplies lower than 0.5V because both the ADJ and V2 inputs have a nominal 0.5V threshold with ±1.5% accuracy (492.5mV to 507.5mV). To supervise sub-0.5V rails, an external level-shifting circuit or a dedicated low-voltage supervisor such as the LTC2912 (with 0.4V threshold option) would be required. The LTC2911IDDB-5 is optimized for 0.5V and above.

What is the role of the exposed pad on the DFN package of the LTC2911IDDB-5?

The exposed pad (pin 9) on the LTC2911IDDB-5's DFN package is internally connected to GND and serves as a thermal and electrical enhancement. While optional for electrical functionality, connecting it to a PCB ground plane significantly improves thermal dissipation (reducing θ_JA from 76°C/W to ~40°C/W in typical layouts) and lowers noise susceptibility. It must not be left floating in thermally demanding applications.

Does the LTC2911IDDB-5 support latching RST high or low independently?

Yes - the LTC2911IDDB-5 supports latching RST in either state via the TMR pin. Pulling TMR to GND latches the *current* RST state: if RST is high when TMR is pulled low, it remains high after release (provided inputs are valid); if RST is low, it stays low. This enables deterministic margin testing under both asserted and deasserted reset conditions without modifying system voltage rails.