Texas Instruments TL7757IDR

Overview

TL7757IDR from Texas Instruments is a precision supply-voltage supervisor IC designed for microcomputer and microprocessor system reset management. It monitors VCC for undervoltage conditions, asserts active-low RESET when VCC drops below 4.55 V ±120 mV, provides 20 mA sink capability, operates down to 1 V VCC, and features 50 mV typical hysteresis to prevent erratic resets - used in industrial control power-up sequencing.

For engineers reviewing the TL7757IDR datasheet, TL7757IDR pinout, TL7757IDR application, or TL7757IDR equivalent, key selection criteria include its −40°C to +85°C operating range, SOIC-8 package, 20 µA standby current, defined RESET behavior below 1 V, and compatibility with 5 V logic rail supervision.

Technical Context

The TL7757IDR implements a precision bandgap-based voltage detector with comparator hysteresis to reject noise-induced false triggers. Its internal circuitry generates a clean, glitch-free active-low RESET signal during power-up and brownout events without external components.

It functions as a standalone power-on reset (POR) generator with automatic recovery: RESET remains asserted until VCC rises above VIT+ (≈4.65 V), then holds for a minimum pulse width (>5 µs) before deasserting. No external capacitor or resistor is required for basic operation.

Key Specifications

Pinout & Package

TL7757IDR is housed in an 8-pin SOIC (D) package per JEDEC MS-012 variation AA, with 1.27 mm pitch, 3.91 mm body width, and 1.75 mm max height. Pin 1 is located at the top-left corner with notch or beveled edge marking.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TL7757IDR, TPS3808G18DR offers dramatically lower standby current but requires external components for 4.55 V operation, while MAX6326UT46D3+ delivers superior accuracy and smaller size but lacks the TL7757IDR's 1 V operational floor and SOIC-8 mechanical compatibility.

Availability

TL7757IDR is available at Aetrix Electronics and suitable for industrial automation, automotive electronics, and medical device applications requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for TL7757IDR 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 leader specializing in analog, embedded processing, and power management technologies, with decades of experience in high-reliability industrial and automotive ICs.

The TL77xx family was engineered specifically for robust, zero-component power-supply supervision in microcontroller-based systems - emphasizing precision threshold stability, wide temperature operation, and fail-safe reset generation.

FAQ

What is the minimum VCC voltage at which TL7757IDR guarantees defined RESET output behavior?

The TL7757IDR guarantees defined RESET output behavior when VCC exceeds 1 V. Below this level, the internal circuitry is not powered sufficiently to ensure predictable logic states. This 1 V specification allows TL7757IDR to maintain deterministic reset assertion during very slow power ramps or deep brownouts - a critical capability for systems with battery backup or wide-input DC-DC converters. The TL7757IDR remains fully functional across its entire −40°C to +85°C operating range at this 1 V threshold.

Does TL7757IDR require external components to function as a basic power-on reset generator?

No, TL7757IDR requires no external components to function as a basic power-on reset generator. Its internal precision voltage reference, comparator, and hysteresis network are fully integrated. Only VCC, GND, and a pull-up resistor on the RESET pin (typically 10 kΩ to VCC) are needed for standard operation. The absence of required timing capacitors or resistor dividers simplifies design, reduces BOM cost, and improves reliability - making TL7757IDR ideal for cost-sensitive and space-constrained applications where 4.55 V threshold supervision is sufficient.

What is the RESET output configuration of TL7757IDR, and how should it be interfaced?

TL7757IDR features an active-low, open-drain RESET output. It must be pulled up to the monitored VCC rail (or another compatible logic rail) via an external resistor - typically 4.7 kΩ to 10 kΩ. The output can sink up to 20 mA, enabling direct interface with standard TTL/CMOS reset inputs without additional buffering. This configuration allows wired-OR connectivity for multiple supervisors and ensures safe reset assertion even if the host system's VCC is absent, provided the pull-up source remains valid.

How does hysteresis in TL7757IDR improve system reliability during supply fluctuations?

TL7757IDR incorporates 50 mV typical hysteresis between its rising-edge threshold (VIT+ ≈ 4.65 V) and falling-edge threshold (VIT− = 4.55 V). This prevents rapid, repeated RESET toggling when VCC lingers near the detection point due to ripple, load transients, or noise - a condition that could cause MCU lockup or boot-loop failures. By enforcing a 100 mV window, TL7757IDR ensures clean, single-pulse reset assertion and release, significantly enhancing robustness in electrically noisy industrial or automotive environments.

Is TL7757IDR pin-compatible with other members of the TL77xx family, such as TL7705 or TL7701?

No, TL7757IDR is not pin-compatible with TL7705IDR or TL7701IDR. Although all are SOIC-8 voltage supervisors from Texas Instruments, their pinouts differ fundamentally: TL7757IDR uses Pins 1 (RESET), 2 (VCC), 4 (GND), and six NC pins; TL7705IDR places RESET on Pin 8 and includes V_REF on Pin 3; TL7701IDR uses Pin 1 for RESET but assigns different functions to Pins 3, 5, and 7. Substituting without PCB revision will result in incorrect or nonfunctional operation. Always verify pin mapping against the specific device's datasheet before replacement.