Analog Devices Inc. LTC6991CS6#TRPBF

Overview

LTC6991CS6#TRPBF from Analog Devices is a silicon-based low-frequency oscillator IC in the TimerBlox® family, designed for long-duration timing events. It delivers programmable clock periods from 1.024 ms to 9.54 hours (29.1 µHz to 977 Hz), features a reset function to truncate output pulses, supports 2.25 V to 5.5 V single-supply operation, and draws only 55–80 µA supply current. It is used in battery-powered watchdog and wake-up timer applications requiring precise, ultra-low-power timing.

For engineers reviewing the LTC6991CS6#TRPBF datasheet, LTC6991CS6#TRPBF pinout, LTC6991CS6#TRPBF application, or LTC6991CS6#TRPBF equivalent, key selection criteria include its 6-pin TSOT-23 package, ±1.5% max frequency error over temperature, 500 µs start-up time, CMOS output capable of ±20 mA drive, and polarity-selectable active-high/active-low RST/OUT configuration via DIV pin voltage programming.

Technical Context

The LTC6991CS6#TRPBF integrates a master oscillator (up to 1 MHz) 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-setting programmable divider (N_DIV = 1, 8, 64, ..., 2²¹). Its output period is calculated as t_OUT = N_DIV × R_SET / 50 kΩ × 1.024 ms.

Timing control is implemented via resistor-programmed analog inputs: R_SET sets master frequency, while a V₊-referenced 4-bit A/D on the DIV pin selects both N_DIV and polarity (POL bit). The RST pin-whose active state (high/low) and output response (force-low/force-high) are determined by POL-provides glitch-free pulse truncation without halting internal oscillation.

Key Specifications

Pinout & Package

Package: 6-lead Plastic TSOT-23 (S6), 1 mm profile, RoHS-compliant, lead-free finish. Exposed pad not present in S6 package.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LTC6991CS6#TRPBF, the I- and H-grade variants offer identical timing performance and interface but extend guaranteed operation to lower and higher temperatures-making them drop-in replacements when thermal requirements increase, without altering circuit design or layout.

Availability

LTC6991CS6#TRPBF is available at Aetrix Electronics and suitable for battery-powered instrumentation, industrial watchdog systems, and commercial-grade timing modules requiring stable component supply and long-lifecycle support.

Supply support for LTC6991CS6#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 precision instrumentation, industrial automation, communications, and automotive markets.

The TimerBlox® product line-including LTC6991CS6#TRPBF-is engineered for robust, resistor-programmable timing in space-constrained, low-power applications where crystal oscillators or microcontroller-based timers are impractical.

FAQ

What is the maximum clock period achievable with the LTC6991CS6#TRPBF?

The LTC6991CS6#TRPBF supports a maximum output clock period of 34,360 seconds (9.54 hours), achieved when N_DIV = 2²¹ and R_SET = 800 kΩ. This value is confirmed in the Electrical Characteristics table (t_OUT MAX = 34,360 s) and aligns with the 1.024 ms base period scaled by the largest divider setting. The part maintains ±1.5% accuracy across this full range under specified conditions.

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

When POL = 1 (configured via DIV pin voltage), the RST pin becomes active-low: pulling RST low forces the OUT pin high, and releasing RST (to high) allows normal oscillation. This behavior is defined in Table 2 and Figures 3–4 of the datasheet. The LTC6991CS6#TRPBF's internal oscillator continues running regardless of RST state, ensuring deterministic timing resume after reset release.

Can the LTC6991CS6#TRPBF operate from a 2.25 V supply?

Yes, the LTC6991CS6#TRPBF is fully specified for operation from 2.25 V to 5.5 V. At 2.25 V, supply current ranges from 55 µA (R_SET = 800 kΩ) to 135 µA (R_SET = 50 kΩ), and output high/low voltages meet logic thresholds (e.g., V_OH ≥ 2.17 V at I_OUT = –1 mA). All timing parameters-including start-up time and frequency accuracy-remain valid across this supply range.

What is the recommended capacitor value for bypassing the V+ pin of the LTC6991CS6#TRPBF?

The datasheet specifies a 0.1 µF ceramic capacitor placed directly between the V+ pin and GND for optimal noise immunity and stability. This value is stated in the "PIN FUNCTIONS" section (page 7) and reinforced in typical application schematics (e.g., Figure TA01a). Larger values (e.g., 1 µF) may be added in parallel for bulk decoupling, but the 0.1 µF capacitor must remain local to the LTC6991CS6#TRPBF package.

Does the LTC6991CS6#TRPBF require external components to function as a basic oscillator?

Yes-the LTC6991CS6#TRPBF requires at minimum one external resistor (R_SET from SET to GND) to set frequency and a 0.1 µF ceramic capacitor from V+ to GND for supply bypassing. For programmable divider selection, a resistor divider on the DIV pin is also needed. No crystal, inductor, or trimming component is required, making it a true "single-chip oscillator" solution with minimal BOM count.