Texas Instruments TL7733BCD

Overview

TL7733BCD from Texas Instruments is a precision supply-voltage supervisor IC designed as a reset controller for microcomputer and microprocessor systems. It monitors the SENSE input for undervoltage conditions, provides true/complement RESET outputs, features an externally adjustable reset pulse duration via CT pin, and delivers a 2.53 V reference voltage at REF. It operates over 3.6 V to 18 V supply range and supports 0°C to 70°C ambient operation.

For engineers reviewing the TL7733BCD datasheet, TL7733BCD pinout, TL7733BCD application, or TL7733BCD equivalent, key selection considerations include its 3.08 V negative-going threshold (V_IT–), ±10 mV hysteresis, open-collector RESET/RESET outputs requiring external pull resistors, and SOIC-8 package compatibility with standard PCB layouts for embedded power management.

Technical Context

The TL7733BCD implements a precision bandgap-based voltage reference and comparator architecture to detect supply drops at the SENSE input. Its internal timing capacitor charging circuit (CT pin) generates a user-defined reset pulse duration governed by t_d ≈ 2.6 × 10⁴ × C_T, where C_T is in farads.

It supports dual-mode reset control: automatic response to SENSE undervoltage and forced reset assertion via RESIN input. The REF output provides a stable 2.53 V ±0.05 V reference for external circuitry, while RESET and RESET outputs are open-drain/open-collector with 16 mA sink/source capability and defined behavior down to V_CC ≥ 1 V.

Key Specifications

Pinout & Package

TL7733BCD is housed in an SOIC-8 (D) package measuring 4.90 mm × 3.91 mm, with gull-wing leads and RoHS-compliant NiPdAu plating. It is rated 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 supply-voltage supervision applications.

Compared with TPS3808G33DBVR and MAX6326UT33+T, TL7733BCD uniquely combines adjustable reset timing, a buffered 2.53 V reference, and wide 3.6–18 V operation-making it optimal for industrial 3.3 V rail supervision where design flexibility and signal integrity are critical.

Availability

TL7733BCD is available at Aetrix Electronics and suitable for industrial PLC control, network router power management, medical diagnostic instrumentation, and smart energy meter applications requiring stable component supply and long-term manufacturability.

Supply support for TL7733BCD 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 specializing in analog, embedded processing, and digital signal technologies, with leadership in power management and precision analog ICs.

The TL77xxB family was engineered specifically for robust, cost-effective reset control in microprocessor-based systems-emphasizing precision threshold detection, configurable timing, and dual-output flexibility across industrial temperature ranges.

FAQ

What is the exact undervoltage detection threshold of the TL7733BCD?

The TL7733BCD has a nominal negative-going input threshold voltage (V_IT–) of 3.08 V at 25°C, with a guaranteed range of 3.03 V to 3.13 V across the full 0°C to 70°C operating temperature range. This threshold is factory-trimmed and temperature-compensated, making TL7733BCD suitable for accurate supervision of 3.3 V power rails where margin above 3.0 V is critical.

How does the CT pin on the TL7733BCD determine reset pulse duration?

The CT pin on the TL7733BCD connects to an external capacitor that sets the reset pulse width using the formula t_d ≈ 2.6 × 10⁴ × C_T, where C_T is in farads. For example, a 0.1 µF capacitor yields approximately 2.6 ms. The internal current source charges CT until it reaches a reference voltage (~1.8 V), then discharges to ~0.6 V-ensuring consistent timing independent of V_CC within its operating range.

Why does the TL7733BCD require external pullup/pulldown resistors on RESET and RESET outputs?

The TL7733BCD uses open-collector outputs for both RESET and RESET pins, meaning they can only actively sink current-not source it. External pullup (for RESET) and pulldown (for RESET) resistors are required to establish valid logic HIGH and LOW voltage levels compatible with downstream microcontrollers or FPGAs. TI recommends 10 kΩ resistors for both to ensure fast edge rates and prevent waveform plateauing.

Can the TL7733BCD monitor a 3.3 V supply directly without external resistive dividers?

Yes-the TL7733BCD's 3.08 V threshold is specifically designed for direct monitoring of 3.3 V supplies at the SENSE pin. No voltage divider is needed, preserving accuracy and eliminating resistor tolerance errors. The device's 10 mV hysteresis further ensures noise immunity during normal operation, and its ability to assert RESET from V_CC ≥ 1 V guarantees reliable behavior during power-up sequencing of the 3.3 V rail.

What is the function of the REF pin on the TL7733BCD, and how should it be used?

REF is a buffered 2.53 V ±0.05 V reference voltage output on the TL7733BCD, derived from an internal temperature-compensated bandgap. It must be decoupled with a 0.1 µF capacitor to GND to suppress transients and prevent false resets. REF can serve as a precision bias for external comparators, ADC references, or sensor conditioning circuits-adding system-level functionality beyond basic reset control.