Analog Devices Inc. LTC6991IDCB#TRPBF

Overview

LTC6991IDCB#TRPBF from Analog Devices is a silicon-based low-frequency oscillator IC designed for long-duration timing events, featuring programmable clock periods from 1.024 ms to 9.54 hours (29.1 µHz to 977 Hz), ±1.5% frequency accuracy over temperature, and CMOS output capable of sourcing/sinking 20 mA. It operates from a single 2.25 V to 5.5 V supply and consumes as little as 55 µA, making it ideal for battery-powered watchdog and wake-up timer applications.

For engineers reviewing the LTC6991IDCB#TRPBF datasheet, LTC6991IDCB#TRPBF pinout, LTC6991IDCB#TRPBF application, or LTC6991IDCB#TRPBF equivalent, key selection criteria include its 6-lead DFN package, reset-triggered duty-cycle truncation, polarity-selectable RST/OUT logic, 500 µs start-up time, and AEC-Q100 qualification for automotive-grade reliability.

Technical Context

The LTC6991IDCB#TRPBF integrates a master oscillator (1 MHz max) controlled by SET-pin current (I_SET = V_SET/R_SET, where V_SET is regulated to 1.00 V ±30 mV), followed by a fixed ÷1024 divider and an 8-step programmable divider (N_DIV = 1 to 2²¹) selected via a 4-bit A/D converter on the DIV pin. Its internal POR circuit ensures reliable start-up with t_START = 500 × t_MASTER.

Reset behavior is polarity-configurable: when POL = 0 (DIVCODE 0–7), RST high forces OUT low; when POL = 1 (DIVCODE 8–15), RST low forces OUT high. The RST pin exhibits hysteresis with thresholds proportional to V+, and propagation delay is 16 ns (V+ = 5.5 V).

Key Specifications

Pinout & Package

Package: 6-lead plastic DFN (2 mm × 3 mm, 1 mm height), exposed pad connected to GND. Pin 7 (exposed pad) is electrically tied to GND and may be soldered to PCB ground plane for thermal and EMI performance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LTC6991IS6#TRPBF, the LTC6991IDCB#TRPBF offers superior thermal performance and board-level stability in high-vibration environments; compared with MAX6372CSA+, it delivers full programmability, precision timing, and dual-mode reset control essential for adaptive power management.

Availability

LTC6991IDCB#TRPBF is available at Aetrix Electronics and suitable for industrial control systems, automotive body electronics, and battery-powered IoT sensor nodes requiring stable component supply and long-term lifecycle support.

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

The TimerBlox® family-including the LTC6991IDCB#TRPBF-is engineered for precision, low-power, and ease-of-use in timing-critical embedded systems where traditional RC oscillators lack accuracy and stability.

FAQ

What is the maximum clock period achievable with the LTC6991IDCB#TRPBF?

The LTC6991IDCB#TRPBF supports a maximum output clock period of 34,360 seconds (9.54 hours), achieved when NDIV = 2²¹ and R_SET = 800 kΩ. This value is guaranteed per the Electrical Characteristics table (t_OUT MAX = 34,360 s) and validated across the –40°C to +85°C operating range for the I-grade device. Longer periods require external counters or cascaded timing stages.

How does the RST pin behave when the POL bit is set to 1?

When POL = 1 (i.e., DIVCODE = 8–15), the RST pin is active-low: pulling RST low forces the OUT pin high (reset state), and releasing RST (to V+) allows normal oscillation to resume. This behavior is confirmed in Table 2 and Figures 3–4 of the datasheet. The LTC6991IDCB#TRPBF continues internal oscillation regardless of RST state, ensuring glitch-free transitions and deterministic timing recovery.

Can the LTC6991IDCB#TRPBF operate from a 2.25 V supply while driving a 20 mA load?

Yes-the LTC6991IDCB#TRPBF guarantees ±20 mA output drive capability across its full 2.25 V to 5.5 V supply range, including at V+ = 2.25 V (see VOH/VOL specifications in Electrical Characteristics). At 2.25 V, VOL ≤ 0.54 V at I_OUT = 8 mA sink, and VOH ≥ 1.58 V at I_OUT = 8 mA source, satisfying standard CMOS logic thresholds for interfacing with 2.5 V–compatible peripherals.

What is the recommended maximum capacitance on the DIV pin for stable operation?

The datasheet specifies a maximum capacitance of 100 pF on the DIV pin to ensure rapid settling of VDIV and accurate A/D conversion of DIVCODE. Exceeding this limit risks misreading the programmed NDIV or POL setting, especially during power-up or dynamic DIVCODE changes. For optimal performance, keep DIV pin trace length short, avoid nearby noisy signals, and use 1% resistors in the voltage divider-exactly as specified for the LTC6991IDCB#TRPBF.

Is the LTC6991IDCB#TRPBF pin-compatible with other TimerBlox devices like the LTC6992 or LTC6993?

No-the LTC6991IDCB#TRPBF has a unique 6-pin DFN pinout (V+, DIV, SET, RST, GND, OUT) and is not pin-compatible with LTC6992 (8-pin) or LTC6993 (6-pin but different function mapping). Each TimerBlox device serves a distinct function: LTC6991 is a programmable oscillator, LTC6992 is a pulse-width modulator, and LTC6993 is a voltage-controlled oscillator. Substituting them requires PCB redesign and firmware adaptation; the LTC6991IDCB#TRPBF must be used where long-period, resettable oscillation is required.