Texas Instruments TL7705BID

Overview

TL7705BID 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 a temperature-compensated 2.53-V reference (REF), supports adjustable reset pulse duration via external CT capacitor, and operates across –40°C to 85°C in SOIC-8 package.

For engineers reviewing the TL7705BID datasheet, TL7705BID pinout, TL7705BID application, or TL7705BID equivalent, this page delivers verified electrical characteristics (V_IT– = 4.55 V typ, V_REF = 2.53 V, I_CC = 3 mA max), thermal metrics (R_θJA = 109.2°C/W), timing behavior (t_PLH/t_PHL = 500 ns max), and functional mode details for reliable system-level reset design.

Technical Context

The TL7705BID implements a dual-threshold voltage supervision architecture with hysteresis (V_HYS = 30 mV) to prevent chatter during supply transients. Its internal precision bandgap reference feeds both the SENSE comparator and REF output, enabling accurate 4.55-V undervoltage detection independent of V_CC variations between 3.6 V and 18 V.

Reset assertion is triggered when SENSE falls below V_IT–; deassertion occurs after a user-defined delay (t_d ≈ 2.6×10⁴ × C_T) once SENSE exceeds V_IT+. The RESIN pin allows external override of reset state, while open-collector RESET/RESET outputs require external pullup/pulldown resistors per TI layout guidance.

Key Specifications

Pinout & Package

TL7705BID is housed in an 8-pin SOIC (D) package measuring 4.90 mm × 3.91 mm, with standard JEDEC MS-012AC footprint and RoHS-compliant NiPdAu lead finish (Level-2-260°C-1 year MSL rating).

Key Features

Applications

Equivalent & Alternatives

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

Compared with TL7705BID, TPS3808G33DBVR offers superior power efficiency but sacrifices configurability and dual-output capability, while MAX6326UT46D3+T delivers tighter threshold accuracy yet omits the critical RESIN control and REF output needed for complex reset sequencing.

Availability

TL7705BID is available at Aetrix Electronics and suitable for industrial PLC controllers, 5-V microcontroller-based gateways, network-attached storage enclosures, and building management system controllers requiring stable component supply across extended temperature ranges.

Supply support for TL7705BID 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 delivering analog, embedded processing, and connectivity solutions for industrial, automotive, and communications markets.

TL7705BID belongs to TI's legacy supply-voltage supervisor product line, engineered specifically for robust reset control in microprocessor systems operating from 3.6 V to 18 V with extended temperature support up to +85°C.

FAQ

What is the exact undervoltage detection threshold for TL7705BID?

The TL7705BID has a nominal negative-going input threshold voltage (V_IT–) of 4.55 V at 25°C, with guaranteed minimum/maximum values of 4.45 V and 4.65 V across its full operating temperature range (–40°C to +85°C). This precise 4.55-V threshold is optimized for reliable reset initiation in standard 5-V microprocessor systems before logic levels become invalid.

How does the CT pin function in TL7705BID, and what capacitor value sets a 2.6-ms reset pulse?

The CT pin on TL7705BID connects to an external timing capacitor that controls reset pulse duration via t_d ≈ 2.6×10⁴ × C_T (with C_T in farads and t_d in seconds). A 0.1-µF capacitor yields approximately 2.6 ms delay, matching TI's recommended value for robust system reset hold time. The internal current source charges CT to ~1.8 V, and discharge terminates near 0.6 V-not ground-ensuring predictable timing.

Why does TL7705BID require separate pullup and pulldown resistors on RESET and RESET outputs?

TL7705BID's RESET (active-high) and RESET (active-low) outputs are both open-collector, requiring external termination to define logic states. TI mandates matched 10-kΩ resistors on both outputs-even if only one is used-to prevent waveform plateauing during switching transitions, which could cause undefined states or delayed system reset. Mismatched termination risks metastability in downstream logic interfaces.

Can TL7705BID monitor VCC directly, or must it use a resistor divider on the SENSE pin?

TL7705BID can monitor VCC directly at the SENSE pin when the supply is ≤5 V, but TI strongly recommends adding a series current-limiting resistor (RT > 560 Ω for 5-V systems) between VCC and SENSE to prevent false triggering during rapid VCC slewing. Without RT, internal CT discharge paths may activate erroneously when VCC collapses faster than the timing capacitor discharges, causing spurious reset assertions.

What is the purpose of the REF pin on TL7705BID, and how must it be decoupled?

The REF pin on TL7705BID delivers a precision 2.53-V temperature-compensated reference voltage for external circuit use. TI requires a 0.1-µF ceramic capacitor connected directly from REF to GND to suppress fast transients and high-frequency noise that could couple into the internal reference node and cause false reset activation. This decoupling is mandatory per TI's layout guidelines and functional description.