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Texas Instruments TL7705BQD
- Part No.:
- TL7705BQD
- Manufacturer:
- Texas Instruments
- Category:
- Supervisors
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
TL7705BQD.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:282
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Product details
Overview
TL7705BQD from Texas Instruments is a precision supply-voltage supervisor IC designed as a reset controller for microprocessor and microcontroller systems. It monitors the SENSE input for undervoltage conditions, provides true/complement RESET outputs, features a 4.55 V (typ) negative-going threshold, supports –40°C to 125°C operation, and uses an external CT capacitor to set reset pulse duration-enabling reliable power-on and brownout reset in industrial motor drives.
For engineers reviewing the TL7705BQD datasheet, TL7705BQD pinout, TL7705BQD application, or TL7705BQD equivalent, key selection considerations include its wide 3.6–18 V supply range, temperature-compensated 2.53 V reference output, open-collector RESET/RESET outputs requiring external pull resistors, and Q-grade automotive-qualified thermal rating up to 125°C.
Technical Context
The TL7705BQD implements a precision voltage-sensing comparator with hysteresis (30 mV typ), referenced to an internal temperature-compensated bandgap. Its RESIN pin enables manual reset override, while the CT pin connects to an external capacitor that sets the reset timeout via a 26 µA internal current source (td ≈ 2.6×10⁴ × CT).
It operates across a 3.6–18 V VCC range and guarantees defined RESET behavior down to VCC ≥ 1 V. The dual active-high/active-low reset outputs support direct interfacing with diverse microcontroller reset inputs without level-shifting.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VIT− Threshold | 4.55 V (typ), ±0.05 V over full temp range - ensures stable 5 V rail supervision with margin against ripple-induced false triggers |
| Hysteresis | 30 mV (typ) - prevents oscillation during slow supply recovery near threshold |
| VREF Output | 2.53 V (typ), ±5 mV at 25°C - usable as precision reference for ADCs or comparators in same system |
| Operating Temp | –40°C to +125°C - qualified for under-hood automotive and high-temp industrial control environments |
| Supply Range | 3.6 V to 18 V - supports 5 V, 12 V, and 15 V logic/motor control rails without external regulation |
| Reset Pulse Delay | Adjustable via CT capacitor (e.g., 0.1 µF → ~2.6 ms) - ensures sufficient hold time for full microcontroller initialization |
| ICC | 3 mA max at 18 V - low quiescent current suitable for always-on monitoring in battery-backed systems |
Pinout & Package
TL7705BQD is housed in an SOIC-8 (D) package measuring 4.90 mm × 3.91 mm, with standard 1.27 mm pitch and gull-wing leads compatible with automated PCB assembly.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (REF) | Reference voltage output | Provides stable 2.53 V reference; requires 0.1 µF bypass capacitor to GND for noise immunity |
| 2 (RESIN) | Reset input | Active-low manual reset override: pulls RESET high / RESET low when asserted |
| 3 (CT) | Timing capacitor connection | Controls reset pulse duration via external capacitor; charges at ~26 µA to ~1.8 V reference |
| 4 (GND) | Ground reference | System ground return for all internal circuitry and output drivers |
| 5 (RESET) | Active-low reset output | Open-collector output; requires external pullup resistor to host VCC (e.g., 10 kΩ) |
| 6 (RESET) | Active-high reset output | Open-collector output; requires external pulldown resistor (e.g., 10 kΩ) if used |
| 7 (SENSE) | Supply voltage monitor input | High-impedance input sensing regulated rail; threshold accuracy maintained over full temperature range |
| 8 (VCC) | Power supply input | Accepts 3.6–18 V; powers internal circuitry and enables RESET output definition down to 1 V |
Key Features
| Feature | Design Value |
|---|---|
| True and complement reset outputs | Simultaneous active-high and active-low signals eliminate need for external inverters in mixed-logic systems |
| Externally adjustable pulse duration | CT pin enables precise, board-level tuning of reset hold time without firmware changes or component replacement |
| Precision voltage sensor with hysteresis | 30 mV hysteresis prevents chatter during marginal supply conditions, improving system reliability in noisy environments |
| RESET output defined from VCC ≥ 1 V | Enables early reset assertion during power-up, even before main regulator stabilizes - critical for fail-safe boot sequences |
| Temperature-compensated reference | 2.53 V REF output maintains ±5 mV stability from –40°C to +125°C, supporting accurate analog subsystem calibration |
Applications
| Industrial Motor Drives | Automotive Body Control Modules |
|---|---|
Use Scenario: Monitoring 12 V battery-supplied MCU in pump/inverter control units exposed to load dump and cold-crank transients. IC Role / Device Role / Timing Role: Voltage supervisor providing brownout reset and power-on reset with 125°C operation and 4.55 V threshold aligned to 12 V rail regulation tolerance. Use Value: Prevents MCU lockup during engine cranking by asserting reset until supply recovers above 4.55 V with 30 mV hysteresis. | Use Scenario: Reset management for infotainment SoC powered from switched 5 V rail with variable load and thermal cycling. IC Role / Device Role / Timing Role: Dual-output reset controller delivering both active-high and active-low signals to match SoC reset architecture requirements. Use Value: Eliminates need for discrete inverter or level shifter, reducing BOM count and layout area while ensuring deterministic reset timing. |
| Factory Automation PLCs | Energy Metering Gateways |
Use Scenario: Supervising isolated 5 V DC-DC output powering ARM-based controller in dusty, high-EMI factory floor enclosures. IC Role / Device Role / Timing Role: Precision voltage monitor with REF output used as ADC reference for current/voltage sensing circuits. Use Value: Single-component solution delivers both reset control and stable 2.53 V reference, improving measurement accuracy and reducing component count. | Use Scenario: Ensuring reliable boot sequence in smart meter gateways operating continuously at elevated ambient temperatures. IC Role / Device Role / Timing Role: High-temp qualified supervisor maintaining reset integrity up to 125°C junction temperature in sealed, convection-limited housings. Use Value: Guarantees functional safety compliance by preventing undefined MCU state during thermal stress events. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar voltage supervisor applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS3839G33DBVR | Fixed 3.3 V threshold, 1.8 µA IQ, SOT-23-6 package | Lacks dual reset outputs and adjustable delay; optimized for ultra-low-power portable devices | Select when lowest quiescent current and smallest footprint are prioritized over flexibility and high-temp operation |
| MAX6326UT46D3+ | 4.63 V threshold, 1.25 µA IQ, SC70-5, no REF output | No reference voltage output; tighter threshold tolerance (±0.5%) but limited to 85°C max ambient | Choose for cost-sensitive consumer applications where 85°C rating suffices and REF is unnecessary |
Compared with TPS3839G33DBVR and MAX6326UT46D3+, TL7705BQD offers unique value in high-temperature industrial designs requiring dual reset polarity, user-adjustable timing, and a precision reference output - capabilities not jointly available in either alternative.
Availability
TL7705BQD is available at Aetrix Electronics and suitable for industrial motor drives, automotive body control modules, factory automation PLCs, and energy metering gateways requiring stable component supply across extended temperature ranges.
Supply support for TL7705BQD 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 and embedded processing technologies, with leadership in power management, signal chain, and high-reliability ICs.
The TL77xxB family was developed specifically for robust reset control in microprocessor-based systems operating under harsh electrical and thermal conditions - emphasizing precision threshold accuracy, wide supply range, and extended temperature qualification.
FAQ
What is the exact reset threshold voltage of TL7705BQD and how does it vary with temperature?
The TL7705BQD has a nominal negative-going threshold voltage (VIT−) of 4.55 V at 25°C, with a guaranteed range of 4.45 V to 4.65 V across its full operating temperature range of –40°C to +125°C. This specification is confirmed in Section 6.5 of the official TI datasheet SLVS037O, and the variation is linear and monotonic, as shown in Figure 9-2. The TL7705BQD maintains this tight threshold tolerance without external calibration, making it suitable for 5 V rail supervision in thermally demanding applications.
Does TL7705BQD require external pullup/pulldown resistors on its RESET and RESET outputs?
Yes, TL7705BQD requires external resistors: a pullup resistor (typically 10 kΩ) on the active-high RESET pin and a pulldown resistor (also typically 10 kΩ) on the active-low RESET pin. Both outputs are open-collector and cannot drive high-side logic levels without external termination. TI explicitly states in Section 9.2.1 and Figure 11-1 that matching resistor values must be used on both outputs-even if only one is utilized-to prevent waveform plateauing and ensure clean, deterministic reset transitions. This requirement applies directly to every TL7705BQD implementation.
Can TL7705BQD monitor a 3.3 V supply rail?
No, TL7705BQD is not suitable for direct 3.3 V rail supervision because its fixed threshold is 4.55 V (nominal). Attempting to use it on a 3.3 V rail would result in permanent reset assertion, as the SENSE input voltage never reaches the required threshold. For 3.3 V systems, TI recommends the TL7702B (2.53 V threshold) or TL7733B (3.08 V threshold). The TL7705BQD is specifically designed for 5 V and higher supply rails, and this functional limitation is clearly defined in the Electrical Characteristics table of the TL7705BQD datasheet.
What is the purpose of the CT pin on TL7705BQD and how is the reset timeout calculated?
The CT pin on TL7705BQD connects to an external capacitor that sets the duration of the reset pulse after supply recovery. An internal 26 µA current source charges the capacitor until it reaches ~1.8 V, triggering reset deassertion. The timeout is approximated by td ≈ 2.6 × 10⁴ × CT, where CT is in farads and td in seconds - so a 0.1 µF capacitor yields ~2.6 ms. This relationship is specified in Section 8.3.2 and validated in Figure 6-3 of the TL7705BQD datasheet, and the calculation holds across the full temperature range.
Is TL7705BQD pin-compatible with other members of the TL77xxB family such as TL7702B or TL7733B?
Yes, TL7705BQD is pin-compatible with TL7702B and TL7733B in the same SOIC-8 (D) package - all share identical pin configuration, function mapping, and electrical interface per Figure 5-1 and Table 5-1 of the datasheet. However, threshold voltages differ (2.53 V, 4.55 V, 3.08 V respectively), so substituting TL7705BQD for another variant requires verification that the 4.55 V threshold matches the target supply rail. The pin compatibility is explicit in TI's mechanical documentation and confirmed across all TL77xxB ordering variants including TL7705BQD.
TL7705BQD Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Bulk
- Product Status:
- Active
- Programmable:
- Not Verified
- Type:
- Simple Reset/Power-On Reset
- Number of Voltages Monitored:
- 1
- Voltage - Threshold:
- 4.55V
- Output:
- Open Drain or Open Collector
- Reset:
- Active High/Active Low
- Reset Timeout:
- 270ns Typical Propagation Delay
- Operating Temperature:
- -40°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
TL7705BQD FAQ
1.How can I place an order for TL7705BQD through Aetrix?
Please submit a Request for Quotation (RFQ) for TL7705BQD on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for TL7705BQD reliable?
The price and inventory of TL7705BQD are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TL7705BQD is usually 5 days.
3.What payment methods are accepted for TL7705BQD?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TL7705BQD transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TL7705BQD?
TL7705BQD orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TL7705BQD order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for TL7705BQD?
For technical support, including TL7705BQD datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TL7705BQD requirements.
6.How does Aetrix verify that TL7705BQD is sourced from the original manufacturer or authorized distributors?
All TL7705BQD products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that TL7705BQD meets industry standards.
7.What is the process for return or replacement of TL7705BQD?
All TL7705BQD units undergo pre-shipment inspection (PSI). If there is an issue with TL7705BQD, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The TL7705BQD part is unused and in its original packaging.
Return procedure for TL7705BQD:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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