Analog Devices Inc. LTC2909IDDB-3.3#TRM

Overview

LTC2909IDDB-3.3#TRM from Analog Devices (formerly Linear Technology) is a precision triple-input voltage supervisor IC for system power monitoring, featuring two adjustable 0.5V-threshold inputs with pin-selectable polarity (±UV/OV), a fixed 2.921V VCC UVLO monitor (±1.5% accuracy), 200ms internal reset timeout, and open-drain RST output. It operates down to 0.5V VCC and supports negative supply monitoring via buffered 1.000V REF, used in 3.3V logic systems requiring robust brownout detection.

For engineers reviewing the LTC2909IDDB-3.3#TRM datasheet, LTC2909IDDB-3.3#TRM pinout, LTC2909IDDB-3.3#TRM application, or LTC2909IDDB-3.3#TRM equivalent, key selection criteria include input polarity configuration via SEL pin, guaranteed 0.5V ADJ threshold accuracy over –40°C to +85°C, ultralow 50μA quiescent current, 6.5V internal shunt regulator capability, and compatibility with 3mm × 2mm DFN-8 packaging for space-constrained embedded designs.

Technical Context

The LTC2909IDDB-3.3#TRM implements dual comparator-based monitoring with independent polarity control per ADJ input via three-state SEL pin (VCC/GND/open), enabling simultaneous positive-UV/negative-OV or dual-negative-UV detection without external components. Its internal 200ms timeout is activated when TMR is tied to GND, while comparator mode (TMR = VCC) bypasses timing for direct fault response.

It integrates a buffered 1.000V reference (±15mV over temperature, ±1mA drive) for offsetting negative-supply dividers, and uses glitch-filtered comparators with 50–500μs propagation delay to suppress transients. The VCC UVLO threshold is fixed at 2.921V (10% below 3.3V nominal) with 0.7% hysteresis only in comparator mode, preserving ±1.5% threshold accuracy across full operating range.

Key Specifications

Pinout & Package

Package: 8-lead 3mm × 2mm plastic DFN (DDB), exposed pad (Pin 9) optional ground connection for thermal management.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar voltage supervisor applications.

Compared with LTC2909CDDB-3.3#TRM, the LTC2909IDDB-3.3#TRM adds guaranteed operation down to –40°C for harsh environments; compared with TPS3808G33DBVR, it provides dual configurable inputs, negative supply support, and integrated reference-enabling complex multi-rail supervision in one device.

Availability

LTC2909IDDB-3.3#TRM is available at Aetrix Electronics and suitable for industrial automation, automotive electronics, and medical device applications requiring stable component supply, long-term lifecycle support, and guaranteed industrial-temperature performance.

Supply support for LTC2909IDDB-3.3#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. (ADI) is a global semiconductor leader specializing in high-performance analog, mixed-signal, and digital signal processing technologies for precision measurement and control systems.

The LTC2909 product line delivers highly accurate, low-power voltage supervision solutions targeting space-constrained, thermally demanding applications in computing, networking, and industrial systems where reliability under voltage fault conditions is critical.

FAQ

What is the guaranteed operating temperature range for the LTC2909IDDB-3.3#TRM?

The LTC2909IDDB-3.3#TRM is rated for industrial temperature operation from –40°C to +85°C. This specification is guaranteed across all key parameters including ADJ input threshold accuracy (±1.5%), VCC UVLO threshold (2.921V ±1.5%), and quiescent current (50μA typical). The DFN-8 package supports this range with θJA = 76°C/W when the exposed pad is properly connected to PCB ground.

How does the SEL pin configure input polarity on the LTC2909IDDB-3.3#TRM?

The SEL pin on the LTC2909IDDB-3.3#TRM selects polarity for both ADJ1 and ADJ2 inputs: tied to VCC enables positive-UV/positive-UV monitoring; tied to GND enables negative-UV/negative-UV; left open enables positive-UV/negative-UV. Each configuration determines whether the input must be above (positive) or below (negative) the 0.5V threshold to maintain RST high. Leakage current on SEL is limited to ±10μA in open state.

Can the LTC2909IDDB-3.3#TRM monitor negative voltages, and if so, how?

Yes, the LTC2909IDDB-3.3#TRM monitors negative voltages using its buffered 1.000V REF output. For a –5V rail, a resistor divider connects between –5V and REF, with ADJ2 tied to the divider midpoint. When SEL = GND, ADJ2 operates in negative-polarity mode: RST asserts low if the ADJ2 voltage rises above 0.5V, indicating the –5V rail has become less negative than its UV threshold (e.g., –4.425V).

What is the function of the TMR pin on the LTC2909IDDB-3.3#TRM, and what are its valid states?

The TMR pin on the LTC2909IDDB-3.3#TRM controls reset timeout behavior: grounded → 200ms internal timeout; tied to VCC → comparator mode (no timeout, direct RST assertion); connected to capacitor → programmable timeout (9ms/nF). In comparator mode, hysteresis (0.7%) is added to prevent oscillation near threshold. TMR leakage is ±2.7μA, and transition currents up to 100μA may occur during state changes.

Does the LTC2909IDDB-3.3#TRM require external components for basic 3.3V system supervision?

For basic 3.3V system supervision, the LTC2909IDDB-3.3#TRM requires only an external pull-up resistor on RST (e.g., 10kΩ to 3.3V) and a 0.1μF bypass capacitor on VCC. No external resistors are needed for VCC UVLO monitoring since it is factory-trimmed to 2.921V. Adjustable inputs (ADJ1/ADJ2) remain unused or tied to REF/GND if only VCC supervision is required.