Texas Instruments TL7757CPK

Overview

TL7757CPK from Texas Instruments is a supply-voltage supervisor and precision voltage detector designed for microcomputer and microprocessor systems. It monitors VCC for undervoltage conditions, asserts active-low RESET below 4.55 V ±120 mV threshold, delivers 20 mA sink capability, operates down to 1 V supply, and features 50 mV typical hysteresis to prevent erratic resets - used in embedded power-on reset circuits for industrial controllers.

For engineers reviewing the TL7757CPK datasheet, TL7757CPK pinout, TL7757CPK application, or TL7757CPK equivalent, key selection criteria include its 4.55 V detection threshold, SOT-89-3 package with thermal resistance of 52°C/W, guaranteed operation from 0°C to 70°C, low 20 µA standby current, and compatibility with 1–7 V supply rails.

Technical Context

The TL7757CPK implements a comparator-based voltage detection architecture with internal resistor-divider network and hysteresis feedback to define precise negative-going threshold (VIT−) and positive-going recovery (VIT+). Its RESET output remains active low until VCC exceeds VIT+ by hysteresis margin, ensuring clean release after brownout recovery.

It integrates a power-on reset generator that activates RESET when VCC rises above ~1 V, independent of final threshold level, preventing undefined MCU state during initial power ramp. The device requires no external components for basic operation and drives standard TTL/CMOS loads directly via open-drain-compatible output stage.

Key Specifications

Pinout & Package

SOT-89-3 (PK) package: 3-pin surface-mount outline with tab connected to GND; compact footprint (4.91 mm × 4.52 mm), 1.9 mm height, moisture sensitivity level 2, peak reflow 260°C.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TL7757CPK, TPS3808G33DBVR offers superior power efficiency but mismatches the 5 V system threshold, while MAX809SEUR+T provides comparable form factor at reduced thermal robustness and looser hysteresis control - TL7757CPK remains optimal for cost-sensitive, thermally demanding 5 V industrial reset applications requiring proven 4.55 V precision.

Availability

TL7757CPK is available at Aetrix Electronics and suitable for industrial PLC controllers, embedded data loggers, point-of-sale terminals, and medical diagnostic instruments requiring stable component supply across extended production lifecycles.

Supply support for TL7757CPK 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 headquartered in Dallas, Texas, delivering analog and embedded processing solutions for industrial, automotive, and personal electronics markets.

The TL77xx family was developed specifically for reliable power-on and brownout reset generation in microcontroller-based systems, emphasizing precision threshold stability, low IQ, and robust noise immunity in cost-sensitive applications.

FAQ

What is the exact reset threshold voltage of TL7757CPK and how does it vary with temperature?

The TL7757CPK has a nominal negative-going input threshold voltage (VIT−) of 4.55 V with ±120 mV tolerance over 0°C to 70°C. Typical hysteresis is 50 mV at 25°C, and VIT− varies from 4.4 V to 4.7 V across the full operating range. Figure 10 in the datasheet shows <10 mV drift from −40°C to 85°C, confirming tight thermal stability for the TL7757C grade. This makes TL7757CPK suitable for applications where 5 V rail monitoring must remain accurate despite ambient fluctuations.

Does TL7757CPK require external components to function as a reset supervisor?

No, TL7757CPK operates autonomously with no external components required. Its internal resistor divider sets the 4.55 V threshold, and the comparator with hysteresis is fully integrated. Only VCC, GND, and the RESET load (e.g., MCU reset pin with pull-up) are needed. Unlike adjustable supervisors, TL7757CPK eliminates BOM items, layout area, and calibration uncertainty - simplifying design while maintaining precision for 5 V systems.

What is the thermal performance of TL7757CPK in the SOT-89 package?

The TL7757CPK in SOT-89 (PK) package has a junction-to-ambient thermal resistance (θJA) of 52°C/W, significantly lower than TO-92 (140°C/W) and SOIC (97°C/W) variants. With its exposed GND tab acting as a thermal path, TL7757CPK sustains continuous 20 mA sink current at elevated ambient temperatures without derating. This makes TL7757CPK ideal for compact, thermally constrained industrial modules where reset reliability must be maintained under sustained load.

Can TL7757CPK drive a reset line with >1000 pF capacitance?

Yes, TL7757CPK can reliably drive reset lines with up to 1000 pF capacitance. Its 20 mA sink capability and 5 µs maximum propagation delay ensure fast edge rates even into heavy capacitive loads - Figure 2 test setup uses CL = 100 pF, and typical rise/fall times are 1 µs max. For >1000 pF, add a series resistor (≤100 Ω) to dampen ringing; TL7757CPK's robust output stage maintains functionality without external buffering in most real-world PCB layouts.

How does TL7757CPK behave during power-up when VCC ramps slowly?

TL7757CPK asserts RESET as soon as VCC exceeds ~1 V (Vres), ensuring early-state MCU protection, then holds RESET active until VCC rises above the 4.55 V threshold plus hysteresis (~4.6 V). Its minimum pulse width requirement is only 5 µs, easily satisfied by typical power supply ramps. Figure 11 shows clean, monotonic RESET deassertion with no chatter - critical for deterministic boot sequences in TL7757CPK-based systems.