STMicroelectronics TL7702ACD1/A

Overview

TL7702ACD1/A from STMicroelectronics is a precision supply voltage supervisor IC designed for power-on and brown-out reset generation in microcontroller systems. It features a 2.5 V threshold voltage (±2%), true/complement reset outputs (RESET/RESET), externally adjustable reset pulse width via capacitor on CT pin, and operates across 3.6 V to 18 V supply range. Used in embedded controllers requiring reliable cold-start and undervoltage protection.

For engineers reviewing the TL7702ACD1/A datasheet, TL7702ACD1/A pinout, TL7702ACD1/A application, or TL7702ACD1/A equivalent, key selection criteria include its fixed 2.5 V sensing threshold, dual active-high/active-low reset outputs, CT-pin-based timing adjustability, temperature-compensated reference, and SO-8 package compatibility with legacy board layouts.

Technical Context

The TL7702ACD1/A integrates a precision bandgap voltage reference and comparator with hysteresis (10–15 mV) to detect supply drops below 2.5 V. Its internal logic generates synchronized high-true and low-true reset signals with programmable delay determined by external CT capacitor (tpo = 1.3×10⁴ × CT).

It supports manual reset assertion via RESIN pin (active-low), maintains output states during supply transients via 0.1 µF REF decoupling, and guarantees operation from 0°C to 70°C. The SENSE input is internally referenced and requires no external resistor divider - unlike TL7705A/TL7709A variants.

Key Specifications

Pinout & Package

TL7702ACD1/A is housed in an SO-8 (Small Outline, 8-pin) surface-mount package with standard 1.27 mm pitch, JEDEC MS-012AC compliant footprint, and plastic body measuring 4.9 mm × 6.0 mm × 1.75 mm.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TL7702ACP and TPS3808G01DBVR, TL7702ACD1/A uniquely delivers fixed 2.5 V sensing with true/complement outputs and user-defined timing in a compact SO-8 - making it optimal for cost-sensitive, volume-produced industrial controllers needing proven reliability and minimal external components.

Availability

TL7702ACD1/A is available at Aetrix Electronics and suitable for industrial PLC controllers, smart energy meters, automotive body control modules, and point-of-sale terminals requiring stable component supply and long-term obsolescence management.

Supply support for TL7702ACD1/A 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

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing analog, MCU, power, and sensor solutions for industrial, automotive, and consumer markets.

TL7700A series belongs to ST's legacy power management supervisor product line, engineered specifically for robust, low-cost reset control in microprocessor-based systems where predictable power-up sequencing and brown-out immunity are essential.

FAQ

What is the function of the REF pin on TL7702ACD1/A?

The REF pin outputs a stabilized 2.5 V reference voltage derived from the internal bandgap. It must be bypassed with a 0.1 µF capacitor to ground to suppress high-frequency noise that could cause false triggering on the SENSE input. This reference is not intended for external use as a precision voltage source but solely serves internal comparator stability and noise rejection.

Can TL7702ACD1/A monitor a 3.3 V supply directly?

Yes - the TL7702ACD1/A is specified to operate with supply voltages as low as 3.6 V and senses down to 2.5 V, making it suitable for monitoring 3.3 V rails. However, per datasheet Note 3, the SENSE input voltage must not exceed Vs − 1 V or 6 V (whichever is less), so at 3.3 V supply, SENSE must remain ≤ 2.3 V - meaning it cannot directly monitor the full 3.3 V rail without attenuation. Use only for rails ≥ 3.6 V or add resistive divider for lower voltages.

How does the CT pin determine reset timeout duration?

The CT pin connects to an external capacitor that sets the reset pulse width tpo using the formula tpo = 1.3 × 10⁴ × CT (seconds). For example, a 0.1 µF capacitor yields tpo ≈ 1.3 ms. This RC-based timing provides design flexibility to match processor-specific reset hold-time requirements without trimming or calibration, and remains stable across temperature and supply variations.

Is TL7702ACD1/A pin-compatible with other TL7700A-series variants?

No - TL7702ACD1/A shares the same SO-8 pinout with TL7705A, TL7709A, etc., but differs electrically: TL7702A has fixed 2.5 V threshold and no external resistor network, while others require R1/R2 dividers to set thresholds (e.g., 4.5 V for TL7705A). Swapping without adjusting external components will result in incorrect trip points or failure to assert reset.