Analog Devices Inc. LTC2909CDDB-3.3#TRPBF

Overview

LTC2909CDDB-3.3#TRPBF from Analog Devices (acquired Linear Technology) is a precision dual-input UV/OV monitor with fixed 3.3V VCC UVLO, ±1.5% threshold accuracy, 50μA quiescent current, and 200ms internal reset timeout - used for reliable power sequencing and fault detection in core voltage rails of embedded computing systems.

For engineers reviewing the LTC2909CDDB-3.3#TRPBF datasheet, LTC2909CDDB-3.3#TRPBF pinout, LTC2909CDDB-3.3#TRPBF application, or LTC2909CDDB-3.3#TRPBF equivalent, key selection criteria include input polarity configurability via SEL pin, buffered 1V reference for negative-supply offset, glitch-filtered comparators, open-drain RST output, and DFN-8 package compatibility with space-constrained PCB layouts.

Technical Context

The LTC2909CDDB-3.3#TRPBF integrates two adjustable 0.5V-threshold comparators with pin-selectable polarity (positive UV/–OV or negative –UV/+OV), a third fixed 2.921V VCC UVLO monitor (±1.5%), and a programmable reset timeout that defaults to 200ms when TMR is grounded. Its buffered 1.000V reference (±15mV over temperature) enables accurate negative-rail monitoring without external components.

It operates from VCC = 0.5V to 6V, features ultralow-voltage reset assertion down to VCC = 0.5V, and includes internal shunt regulation at 6.5V for high-voltage supply operation. Input glitch rejection and propagation delay ≤500μs ensure robust response to brownout and transient events.

Key Specifications

Pinout & Package

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

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual-input voltage monitoring applications.

Compared with TPS3808G33DBVR and MAX6816EUT+T, the LTC2909CDDB-3.3#TRPBF uniquely combines triple monitoring (VCC + dual ADJ), pin-configurable polarity, and a buffered 1V reference - enabling single-IC solutions for complex multi-rail and mixed-polarity systems where accuracy, flexibility, and board area are critical.

Availability

LTC2909CDDB-3.3#TRPBF is available at Aetrix Electronics and suitable for desktop computing, automotive infotainment, and network server applications requiring stable component supply, long-term lifecycle support, and guaranteed parametric compliance.

Supply support for LTC2909CDDB-3.3#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. (ADI) is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving industrial, automotive, communications, and healthcare markets.

The LTC2909 product line delivers precision, low-power, multi-rail voltage supervision ICs designed for mission-critical power integrity in space-constrained embedded systems where reliability and accuracy are non-negotiable.

FAQ

What is the guaranteed VCC UVLO threshold for LTC2909CDDB-3.3#TRPBF?

The LTC2909CDDB-3.3#TRPBF has a guaranteed VCC undervoltage lockout threshold of 2.921V (±1.5%) over its full operating temperature range (0°C to 70°C). This value is fixed and calibrated for 3.3V nominal supply monitoring, ensuring reset assertion before the 3.3V rail falls below functional logic levels. The part's datasheet specifies this as V_CC(UVLO) = 2.921V typ, with min/max bounds of 2.871V and 2.970V.

How does the SEL pin configure input polarity on LTC2909CDDB-3.3#TRPBF?

The SEL pin on LTC2909CDDB-3.3#TRPBF selects polarity for both ADJ1 and ADJ2 inputs: connecting SEL to VCC configures both for positive polarity (UV detection on positive rails), grounding SEL sets both to negative polarity (UV detection on negative rails), and leaving SEL open enables mixed polarity (e.g., ADJ1 positive, ADJ2 negative). This eliminates external logic or resistors, and leakage is limited to ±10μA in the open state per the datasheet.

Can LTC2909CDDB-3.3#TRPBF monitor a negative supply without external op-amps?

Yes. The LTC2909CDDB-3.3#TRPBF includes a buffered 1.000V reference (REF pin) that allows direct negative-supply monitoring: connect the negative rail to a resistor divider whose low side ties to REF instead of GND. With SEL configured appropriately (e.g., SEL = GND for negative polarity), ADJ1 or ADJ2 detects UV when the negative rail rises toward zero. No op-amp or level-shifter is needed - REF sources/sinks ±1mA and drives capacitive loads up to 1000pF.

What is the minimum VCC voltage required for LTC2909CDDB-3.3#TRPBF to assert a valid reset?

The LTC2909CDDB-3.3#TRPBF guarantees valid RST output behavior down to VCC = 0.5V. At this voltage, it asserts RST low with VOL ≤0.15V while sinking 100μA - sufficient to drive standard CMOS inputs. This ultralow-voltage capability ensures deterministic reset during deep brownout or battery-depleted conditions where other supervisors fail to operate.

Does LTC2909CDDB-3.3#TRPBF require an external timing capacitor for basic operation?

No. The LTC2909CDDB-3.3#TRPBF defaults to a 200ms internal reset timeout when the TMR pin is tied to GND - requiring no external capacitor. This simplifies BOM and layout for standard applications. External capacitors are optional only when custom timeout durations (e.g., 16ms to 10s) are needed; TMR = open yields ~400μs, and TMR = VCC disables timeout entirely (comparator mode).