Analog Devices Inc. LTC6991IDCB#TRMPBF

Overview

LTC6991IDCB#TRMPBF from Analog Devices is a programmable silicon oscillator IC designed for long-duration timing events, delivering clock periods from 1.024 ms to 34,360 seconds (29.1 µHz to 977 Hz) with ±1.5% frequency accuracy over –40°C to +85°C. It uses a single RSET resistor and DIV pin voltage to configure NDIV divider settings (1–2²¹) and polarity mode, and features a reset-controlled CMOS output capable of sourcing/sinking 20 mA. It serves as a low-power "heartbeat" or wake-up timer in battery-powered industrial sensors.

For engineers reviewing the LTC6991IDCB#TRMPBF datasheet, LTC6991IDCB#TRMPBF pinout, LTC6991IDCB#TRMPBF application, or LTC6991IDCB#TRMPBF equivalent, key selection criteria include guaranteed –40°C to +85°C operation, DFN-6 (2 mm × 3 mm) package, 55–80 µA supply current at 2.25–5.5 V, 500 µs start-up time, and reset propagation delay under 40 ns - all critical for automotive-grade intervalometers and watchdog systems.

Technical Context

The LTC6991IDCB#TRMPBF implements a master oscillator (1 MHz • 50 kΩ / RSET) followed by a fixed ÷1024 stage and an 8-value programmable divider (NDIV = 1, 8, 64, 512, 4096, 2¹⁵, 2¹⁸, 2²¹), enabling precise low-frequency synthesis. Its SET pin regulates VSET to 1.00 V ±30 mV, making output period tOUT = NDIV × RSET / 50 kΩ × 1.024 ms independent of supply drift when using a single RSET resistor.

Operation relies on a V+-referenced 4-bit A/D converter monitoring the DIV pin to determine both NDIV and the POL bit, which jointly define active-high/low RST behavior and output inversion. The RST pin propagates within 16–40 ns depending on supply voltage and does not halt internal oscillation - only truncates or holds the output latch state.

Key Specifications

Pinout & Package

Package: 6-lead (2 mm × 3 mm) plastic DFN (DCB), exposed pad connected to GND. RoHS-compliant, moisture sensitivity level 1.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar low-frequency oscillator applications.

Compared with MAX6373KA+T and DS3231M+, the LTC6991IDCB#TRMPBF uniquely combines wide-range programmability (ms to hours), hardware reset control, polarity flexibility, and ultra-low quiescent current - making it optimal for autonomous, microcontroller-less timing in harsh environments.

Availability

LTC6991IDCB#TRMPBF is available at Aetrix Electronics and suitable for industrial intervalometers, automotive watchdog timers, portable medical alerts, and high-vibration sensor nodes requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for LTC6991IDCB#TRMPBF 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. is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving industrial, automotive, communications, and healthcare markets.

The LTC6991IDCB#TRMPBF belongs to the TimerBlox® family - silicon timing devices engineered for precision, low power, and ease of use in applications where crystal oscillators or microcontroller-based timers are impractical due to size, cost, or power constraints.

FAQ

What is the guaranteed operating temperature range for LTC6991IDCB#TRMPBF?

The LTC6991IDCB#TRMPBF is specified for –40°C to +85°C operation, with full electrical performance guaranteed across this range per the datasheet's "LTC6991I" grade. This includes parameters such as frequency accuracy (±1.5%), supply current (55–80 µA), and reset propagation delay (16–40 ns). The part is also AEC-Q100 qualified for automotive applications, confirming robustness in thermally demanding environments.

How do I configure LTC6991IDCB#TRMPBF for a 1 Hz output with active-high reset?

To configure LTC6991IDCB#TRMPBF for 1 Hz (1000 ms period) with active-high reset, set POL = 0 by selecting DIVCODE = 2 (NDIV = 64), using R1 = 976 kΩ and R2 = 182 kΩ on the DIV pin. Then calculate RSET = (50 kΩ / 1.024 ms) × (1000 ms / 64) ≈ 763 kΩ; a standard 768 kΩ 1% resistor yields –0.7% error. The LTC6991IDCB#TRMPBF will then generate precise 1 Hz pulses with RST high forcing OUT low.

Does LTC6991IDCB#TRMPBF require external crystals or capacitors?

No, the LTC6991IDCB#TRMPBF is a fully integrated silicon oscillator and requires no external crystal, resonator, or timing capacitor. Only two external components are needed for basic operation: an RSET resistor (50–800 kΩ) from SET to GND to set frequency, and a resistor divider on the DIV pin to select NDIV and polarity. A 0.1 µF bypass capacitor on V+ to GND is recommended for noise immunity, but is not part of the timing network.

Can LTC6991IDCB#TRMPBF drive an LED directly?

Yes, the LTC6991IDCB#TRMPBF CMOS output can source or sink up to 20 mA, sufficient to drive standard indicator LEDs directly. For a typical red LED (2.0 V forward voltage, 10 mA target), connect the LED anode to V+ and cathode to OUT through a current-limiting resistor (e.g., 220 Ω at 3.3 V). Ensure RSET and DIV networks remain isolated from the output trace to prevent jitter; the LTC6991IDCB#TRMPBF's 30 Ω output resistance supports clean switching without external drivers.

What is the start-up behavior of LTC6991IDCB#TRMPBF after power application?

Upon power application, the LTC6991IDCB#TRMPBF asserts a power-on reset (POR) that holds OUT low for tSTART = 500 × tMASTER (typically ≤500 ns at max frequency). During this time, the DIV pin A/D converter samples VDIV to determine DIVCODE. If RST is low at end-of-start-up and POL = 0, OUT begins oscillating immediately; if RST is high, OUT remains low until RST goes low. The LTC6991IDCB#TRMPBF achieves stable output within 500 µs, verified across voltage and temperature.