Analog Devices Inc. LTC6991HS6#TRPBF

Overview

LTC6991HS6#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% max frequency accuracy over temperature, and reset-triggered duty-cycle control. It operates from 2.25 V to 5.5 V, draws as low as 55 µA, and targets automotive-grade systems requiring robustness in –40°C to 125°C environments.

For engineers reviewing the LTC6991HS6#TRPBF datasheet, LTC6991HS6#TRPBF pinout, LTC6991HS6#TRPBF application, or LTC6991HS6#TRPBF equivalent, this page delivers verified technical context, exact pin functions, real-world timing use cases, and validated alternative options - all grounded in Analog Devices' Rev. D specification and AEC-Q100-qualified characterization data.

Technical Context

The LTC6991HS6#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-setting programmable divider (NDIV = 1, 8, 64, ..., 2²¹). Its output period is calculated as t_OUT = NDIV × R_SET/50 kΩ × 1.024 ms.

Timing configuration is achieved via resistor networks on the DIV pin, which feeds a V⁺-referenced 4-bit ADC to determine both NDIV and polarity (POL bit); RST pin behavior (active-high or active-low) and OUT polarity are jointly governed by POL, with reset propagation delay under 40 ns at 2.25 V.

Key Specifications

Pinout & Package

Package: 6-lead 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 MAX6375KA+T and DS1086L+T&R, the LTC6991HS6#TRPBF uniquely combines wide-range analog programmability, reset-triggered pulse control, AEC-Q100 qualification, and sub-80 µA supply current - making it the only option for precision, field-configurable, automotive-grade timing in space- and power-constrained systems.

Availability

LTC6991HS6#TRPBF is available at Aetrix Electronics and suitable for automotive watchdog timers, industrial intervalometers, portable medical device wake-up circuits, and high-vibration equipment timing applications requiring stable component supply across extended temperature ranges.

Supply support for LTC6991HS6#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, automotive, communications, and healthcare markets.

The LTC6991HS6#TRPBF belongs to the TimerBlox® family - silicon timing devices engineered for replacing crystals, RC networks, and microcontroller-based timers in applications demanding long-duration, low-power, and highly stable timing without software overhead.

FAQ

What is the maximum clock period achievable with the LTC6991HS6#TRPBF?

The LTC6991HS6#TRPBF achieves a maximum output clock period of 34,360 seconds (9.54 hours) when configured with NDIV = 2²¹ and R_SET = 800 kΩ. This value is confirmed in the Electrical Characteristics table (Rev. D, p.3) under t_OUT parameter, and applies across the full –40°C to 125°C operating range for the H-grade variant.

Does the LTC6991HS6#TRPBF require an external crystal or resonator?

No, the LTC6991HS6#TRPBF is a fully integrated silicon oscillator and requires no external crystal, resonator, or capacitor for basic operation. Timing is set solely by the R_SET resistor on the SET pin and the resistor divider on the DIV pin - eliminating component count, board area, and crystal-related failure modes such as microphonics or aging drift.

How does the reset function affect the internal oscillator of the LTC6991HS6#TRPBF?

The reset function of the LTC6991HS6#TRPBF only affects the output latch and does not halt the internal master oscillator. As stated in the Operation section (Rev. D, p.11), "The master oscillator frequency and phase are not affected by the RST pin; The LTC6991 continues to oscillate, internally, even when RST is active." This ensures deterministic timing recovery upon reset release.

Can the LTC6991HS6#TRPBF operate from a 2.25 V supply while maintaining full specification?

Yes, the LTC6991HS6#TRPBF is fully specified from 2.25 V to 5.5 V. Electrical Characteristics (Rev. D, p.3) explicitly list V+ = 2.25 V test conditions for parameters including supply current (e.g., 105 µA typ. at R_SET = 50 kΩ), output voltage levels, and frequency accuracy - all guaranteed over the full –40°C to 125°C temperature range.

What is the purpose of the POL bit in the LTC6991HS6#TRPBF, and how is it set?

The POL bit in the LTC6991HS6#TRPBF determines both RST pin polarity (active-high or active-low) and OUT pin inversion. It is the MSB of the 4-bit DIVCODE value, set by the voltage on the DIV pin (VDIV/V+ = (DIVCODE + 0.5)/16 ±1.5%). For example, VDIV/V+ ≈ 0.09375 selects DIVCODE = 1 and POL = 0 (RST active-high); VDIV/V+ ≈ 0.59375 selects DIVCODE = 9 and POL = 1 (RST active-low).