Texas Instruments TL7705BCDRG4

Overview

TL7705BCDRG4 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 an externally adjustable reset pulse duration via CT capacitor, and maintains defined RESET behavior down to VCC ≥ 1 V. It is used in server power sequencing and industrial embedded controllers requiring reliable brownout detection.

For engineers reviewing the TL7705BCDRG4 datasheet, TL7705BCDRG4 pinout, TL7705BCDRG4 application, or TL7705BCDRG4 equivalent, key selection considerations include its 4.55-V nominal undervoltage threshold (VIT–), ±30-mA output drive capability, SOIC-8 package with 4.90 mm × 3.91 mm footprint, temperature-compensated reference voltage (2.53 V typ), and compatibility with 3.6–18-V supply operation.

Technical Context

The TL7705BCDRG4 implements a dual-comparator architecture with precision hysteresis (30 mV typ) and a temperature-compensated bandgap reference. Its SENSE input compares against a trimmed 4.55-V threshold, while the REF output delivers a stable 2.53-V reference for external circuitry. The CT pin interfaces with an internal current source (≈2.6×10⁴ × CT s delay) to set reset timeout duration.

It supports three functional modes: automatic reset assertion on VSENSE drop below VIT–, manual reset override via RESIN (low = forced RESET high / RESET low), and power-on reset initiation at VCC ≥ 1 V. Outputs are open-collector (RESET) and open-drain (RESET), requiring external pull-up/pull-down resistors per TI layout guidance.

Key Specifications

Pinout & Package

TL7705BCDRG4 is housed in an 8-pin SOIC (D) package with 4.90 mm × 3.91 mm body size and standard 1.27-mm lead pitch. Pin 1 is marked by a beveled corner or dot; leads are gull-wing, RoHS-compliant NIPDAU finish, MSL Level-2 (260°C peak reflow).

Key Features

Applications

Equivalent & Alternatives

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

Compared with TL7705BCDRG4, TPS3808G33DBVR offers superior power efficiency but sacrifices design flexibility in timing and reference provision, while MAX6816EUT+T prioritizes ruggedness and compactness at the expense of dual-output control and external timing adjustment.

Availability

TL7705BCDRG4 is available at Aetrix Electronics and suitable for server power sequencing, industrial PLC controllers, network switch ASIC boot, and medical diagnostic equipment requiring stable component supply across commercial temperature range.

Supply support for TL7705BCDRG4 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 microcontrollers.

The TL77xxB family was developed specifically for robust, precision reset control in microprocessor and microcomputer systems, emphasizing threshold accuracy, hysteresis stability, and flexible timing configuration under varying supply conditions.

FAQ

What is the exact undervoltage threshold voltage for TL7705BCDRG4?

The TL7705BCDRG4 has a nominal negative-going input threshold voltage (VIT–) of 4.55 V at 25°C, with a guaranteed range of 4.45 V to 4.65 V across the full 0°C to 70°C operating temperature range. This threshold is factory-trimmed and temperature-compensated to ensure consistent brownout detection for 5-V systems.

Does TL7705BCDRG4 require external pull-up resistors on its reset outputs?

Yes, TL7705BCDRG4 requires external pull-up resistors on the RESET pin (Pin 6) and external pull-down resistors on the RESET pin (Pin 5), as both outputs are open-collector/open-drain. Texas Instruments recommends 10-kΩ resistors to ensure proper logic levels for interfacing with standard microcontroller reset inputs.

How is the reset pulse duration set on TL7705BCDRG4?

The reset pulse duration on TL7705BCDRG4 is set by an external capacitor connected to the CT pin (Pin 3). The time delay follows td ≈ 2.6 × 10⁴ × CT, where CT is in farads and td is in seconds - for example, a 0.1-µF capacitor yields approximately 2.6 ms. TI recommends using a 0.1-µF ceramic capacitor for typical applications.

Can TL7705BCDRG4 monitor its own VCC supply directly?

Yes, TL7705BCDRG4 can monitor its own VCC supply by connecting VCC to the SENSE pin (Pin 7), but TI recommends adding a current-limiting resistor (≥560 Ω) in series with the CT capacitor to prevent false triggering during rapid VCC slewing. This configuration is validated in the datasheet's Figure 10-1.

What is the function of the REF pin on TL7705BCDRG4?

The REF pin (Pin 1) on TL7705BCDRG4 provides a precision 2.53-V (typ) temperature-compensated reference voltage output. It is intended for external use - such as biasing comparators or feeding ADC references - and requires a 0.1-µF bypass capacitor to GND to suppress noise and ensure stability, as specified in Section 6.5 and Figure 11-1 of the datasheet.