Analog Devices Inc. LTC699CS8#TRPBF

Overview

LTC699CS8#TRPBF from Analog Devices (acquired Linear Technology) is a microprocessor supervisory circuit with integrated reset and watchdog timer functions. It provides guaranteed reset assertion down to VCC = 1V, 4.65V precision voltage monitoring, 200ms reset time delay, 1.6s watchdog timeout, and operates from 3.0V to 5.5V supply - used in embedded controllers requiring reliable power-on reset and firmware fault detection.

For engineers reviewing the LTC699CS8#TRPBF datasheet, LTC699CS8#TRPBF pinout, LTC699CS8#TRPBF application, or LTC699CS8#TRPBF equivalent, key selection criteria include guaranteed low-VCC reset hold, open-drain RESET output with 25mA sink capability, SO-8 package compatibility, and precise 4.65V threshold with 40mV hysteresis for noise-immune supply monitoring.

Technical Context

The LTC699CS8#TRPBF integrates a bandgap-referenced precision voltage comparator and a monostable watchdog timer on a single die. Its reset logic asserts an open-drain output when VCC drops below 4.65V (typ), with hysteresis preventing chatter during brownout recovery. The watchdog monitors WDI transitions and forces RESET low if no edge occurs within 1.6s (typ).

RESET remains active low even at VCC = 1V (4mV max output voltage at 10µA sink), ensuring processor hold-down during deep undervoltage. The device disables watchdog functionality when WDI is left floating and enters low-power state when VCC falls below reset threshold.

Key Specifications

Pinout & Package

Package: 8-lead plastic SOIC (S8), 3.9mm × 4.9mm body, 1.27mm pitch, RoHS-compliant.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar microprocessor supervisory applications.

Compared with MAX699CSA+ and TPS3808G33DBVR, the LTC699CS8#TRPBF uniquely combines precision reset supervision with integrated watchdog timing in SO-8, eliminating need for discrete timing components while maintaining guaranteed low-VCC reset hold - critical for fail-safe embedded systems.

Availability

LTC699CS8#TRPBF is available at Aetrix Electronics and suitable for industrial PLC controllers, automotive body control modules, and medical diagnostic instruments requiring stable component supply, long-term lifecycle support, and guaranteed reset behavior across temperature.

Supply support for LTC699CS8#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 technologies, serving industrial, automotive, communications, and healthcare markets.

The LTC699CS8#TRPBF belongs to ADI's legacy Linear Technology supervisory IC family, engineered specifically for robust microprocessor power monitoring and fault recovery in mission-critical embedded systems.

FAQ

What is the guaranteed minimum VCC level at which LTC699CS8#TRPBF maintains active RESET?

The LTC699CS8#TRPBF guarantees RESET remains active low down to VCC = 1V, with output voltage ≤200mV at 10µA sink current. This ensures the microprocessor stays held in reset during deep brownout conditions - a key differentiator versus standard supervisors that release reset above 2.5V. The LTC699CS8#TRPBF achieves this via specialized low-voltage biasing of its internal comparator and output stage.

Does LTC699CS8#TRPBF require external components to operate as a reset supervisor?

No, the LTC699CS8#TRPBF requires only a 0.1µF ceramic bypass capacitor on VCC for stable operation; no external resistors or capacitors are needed for reset threshold or timing. Its 4.65V threshold and 200ms reset pulse are factory-trimmed and temperature-compensated. The LTC699CS8#TRPBF's minimal external component count reduces BOM cost and board area versus adjustable alternatives.

How does the watchdog function behave when the WDI pin is left unconnected?

When the WDI pin of the LTC699CS8#TRPBF is left floating (high-impedance), the internal watchdog timer is disabled and no timeout events occur. This allows safe deployment in systems where watchdog functionality is not required, without risk of unintended resets. The LTC699CS8#TRPBF treats floating WDI as a deliberate disable signal - distinct from driving WDI high or low, which would trigger immediate timeout.

What is the maximum sink current capability of the RESET output on LTC699CS8#TRPBF?

The RESET output of the LTC699CS8#TRPBF is rated for 25mA maximum sink current, with 0.4V max voltage drop at 1.6mA load and VCC = 4.25V. This drives standard µP reset inputs directly and supports wired-OR configurations with multiple supervisors. The LTC699CS8#TRPBF's robust output stage eliminates need for external buffer transistors in most applications.

Is LTC699CS8#TRPBF compatible with 3.3V microprocessor systems?

Yes - the LTC699CS8#TRPBF operates from 3.0V to 5.5V and delivers valid reset signaling across this range. While its 4.65V threshold targets 5V systems, it can supervise 3.3V rails using external resistor-divider feedback (though factory threshold is fixed). For pure 3.3V applications, the LTC699CS8#TRPBF's guaranteed 1V reset hold and low I_Q remain beneficial during power sequencing. Always verify RESET logic levels against target µP requirements.