Texas Instruments TL7705BQDR

Overview

TL7705BQDR from Texas Instruments is a precision supply-voltage supervisor IC designed as a reset controller for 5-V microprocessor systems. It monitors the SENSE input for undervoltage conditions, provides true and complement active-high/active-low RESET outputs, features externally adjustable reset pulse duration via CT pin, and operates across –40°C to 125°C with 4.55 V nominal threshold voltage.

For engineers reviewing the TL7705BQDR datasheet, TL7705BQDR pinout, TL7705BQDR application, or TL7705BQDR equivalent, this page delivers verified specifications, thermal and timing behavior, SOIC-8 package details, real-world implementation guidance for microcontroller reset circuits, and validated alternative options for industrial and automotive-grade voltage monitoring.

Technical Context

The TL7705BQDR implements a precision bandgap-based voltage reference (2.53 V typ) and dual-comparator architecture to detect SENSE voltage drops below 4.55 V (±50 mV over temperature). Its internal current source charges an external CT capacitor to generate a user-defined reset timeout - td ≈ 26 ms per µF - enabling robust fault recovery in noisy power environments.

It supports three functional modes: automatic reset on undervoltage, manual reset override via RESIN, and simultaneous assertion of complementary RESET/RESET outputs. The REF output provides a stable 2.53 V reference for external circuitry, while GND and VCC pins support operation from 3.6 V to 18 V with 3 mA typical supply current.

Key Specifications

Pinout & Package

TL7705BQDR is housed in an 8-pin SOIC (D) package, 4.90 mm × 3.91 mm body size, RoHS-compliant, with NIPDAU lead finish and moisture sensitivity level (MSL) Level-1 (unlimited floor life at ≤30°C/60% RH).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar voltage supervisor applications.

Compared with TPS3808G33DBVR and MAX6326UT46D3+, TL7705BQDR uniquely combines adjustable reset timeout, manual reset override (RESIN), dual complementary outputs, and a buffered reference voltage - making it optimal for complex, thermally demanding 5-V microcontroller supervision where design flexibility and functional completeness are critical.

Availability

TL7705BQDR is available at Aetrix Electronics and suitable for industrial PLC controllers, automotive engine control units, server power management modules, and industrial motor drive HMIs requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for TL7705BQDR 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

Texas Instruments is a global semiconductor company delivering analog and embedded processing solutions, with leadership in power management, signal chain, and high-reliability ICs for industrial, automotive, and communications markets.

The TL77xxB series was developed specifically for robust, temperature-stable reset control in microprocessor-based systems operating under harsh electrical and thermal conditions - emphasizing precision threshold accuracy, flexible timing, and functional redundancy via complementary outputs.

FAQ

What is the exact voltage threshold and tolerance of TL7705BQDR over its full operating temperature range?

The TL7705BQDR has a nominal negative-going input threshold voltage (V_IT–) of 4.55 V at 25°C, with guaranteed limits of 4.45 V (min) to 4.65 V (max) across –40°C to +125°C. This ±50 mV window ensures predictable reset activation for 5-V systems even under extreme thermal stress, and is specified in Section 6.5 of the SLVS037O datasheet.

How does the CT pin on TL7705BQDR determine reset timeout duration, and what capacitor value yields a 2.6-ms pulse?

The CT pin on TL7705BQDR connects to an external capacitor that sets reset pulse duration using td ≈ 2.6 × 10⁴ × C_T, where C_T is in farads and td in seconds. A 0.1-µF capacitor yields approximately 2.6 ms. TI validates this relationship across temperature and supply voltage in Section 8.3.2 and Figure 9-2 of the datasheet.

Does TL7705BQDR require external pull-up resistors on its RESET and RESET outputs, and if so, what value is recommended?

Yes, TL7705BQDR requires external pull-up (for RESET) and pull-down (for RESET) resistors because both outputs are open-collector. Texas Instruments explicitly recommends 10-kΩ resistors in Section 9.2.1 and Figure 11-1 of the datasheet to ensure clean logic transitions and prevent waveform plateauing that could cause undefined reset states.

Can TL7705BQDR monitor its own VCC supply, or must it sense an external rail via the SENSE pin?

TL7705BQDR does not internally monitor V_CC; it exclusively supervises the voltage applied to the SENSE pin. To supervise the 5-V system rail, connect that rail directly to SENSE. V_CC powers the IC but is not sensed - this separation allows independent monitoring of critical downstream rails, as confirmed in Section 3 and Figure 10-1 of the SLVS037O datasheet.

What is the purpose of the REF pin on TL7705BQDR, and how must it be used in a production design?

The REF pin on TL7705BQDR delivers a precision 2.53-V reference voltage for external circuitry. It must be decoupled with a 0.1-µF capacitor to GND, as mandated in Section 8.1 and Figure 11-1 of the datasheet, to suppress high-frequency noise that would otherwise couple into the internal reference and cause false resets during power transients.