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Texas Instruments TPS3705-50D
- Part No.:
- TPS3705-50D
- Manufacturer:
- Texas Instruments
- Category:
- Supervisors
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
TPS3705-50D.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:163
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Product details
Overview
TPS3705-50D from Texas Instruments is a precision 5-V supply voltage supervisor IC with integrated watchdog timer, power-fail comparator, and 200-ms power-on reset delay. It monitors VDD at 4.55 V (±2%), asserts active-low RESET during undervoltage or power failure, and provides WDI/WDO for system-level fault recovery in microprocessor-based systems.
For engineers reviewing the TPS3705-50D datasheet, TPS3705-50D pinout, TPS3705-50D application, or TPS3705-50D equivalent, key selection criteria include its fixed 4.55-V threshold, 1.6-s watchdog timeout, 50 µA max supply current, −40°C to 85°C operation, and compatibility with MSP430 and other low-power MCUs requiring reliable brownout and fail-safe supervision.
Technical Context
The TPS3705-50D implements dual-supervision architecture: a precision bandgap-referenced comparator monitors VDD against 4.55 V with 70 mV hysteresis, while a separate PFI input enables external rail monitoring (e.g., 12 V via resistor divider). Its internal oscillator drives a 1.6-s watchdog timeout, retriggerable by edge transitions on WDI.
RESET assertion occurs when VDD drops below 4.55 V or MR is pulled low; RESET remains active for ≥200 ms after VDD exceeds 4.55 V. PFO asserts low when PFI falls below 1.25 V, enabling low-battery or auxiliary supply failure detection without external components.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VIT– Threshold | 4.55 V ±2% - precise 5-V rail supervision with guaranteed margin against nominal 5-V supply tolerance |
| Reset Delay | 200 ms fixed - ensures stable MCU initialization without external capacitor or timing component |
| Watchdog Timeout | 1.6 s typical - provides deterministic system recovery window for firmware hang detection |
| Supply Current | 50 µA max - enables use in battery-backed or ultra-low-power systems without significant drain |
| Operating Temp | −40°C to 85°C - supports industrial and automotive under-hood applications with full specification compliance |
| Hysteresis | 70 mV on VDD - prevents oscillation during slow-rising/falling supply transitions |
| PFI Threshold | 1.25 V ±0.05 V - allows accurate monitoring of auxiliary rails (e.g., 12 V via 910k/120k divider) for power-fail warning |
Pinout & Package
TPS3705-50D is available in 8-pin SOIC (D package), 3.90 mm × 4.90 mm body size, with exposed pad not present. Pin functions are validated per TI SLVS184F Rev F.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| MR (Pin 1) | Manual Reset Input | Active-low signal to force RESET assertion independent of VDD level; requires pull-up for normal operation |
| VDD (Pin 2) | Supply Voltage Input | Primary 2–6 V power rail connection; powers internal reference, comparators, and watchdog logic |
| GND (Pin 3) | Ground Reference | Common return path for all internal circuits and output drivers; must be low-impedance |
| PFI (Pin 4) | Power-Fail Input | Analog input for monitoring secondary supply; triggers PFO when voltage falls below 1.25 V |
| PFO (Pin 5) | Power-Fail Output | Active-low open-drain output signaling auxiliary supply failure; requires external pull-up |
| WDI (Pin 6) | Watchdog Input | Edge-sensitive trigger for watchdog timer; transition resets 1.6-s timeout period |
| RESET (Pin 7) | Reset Output | Active-low open-drain reset signal for microcontroller; asserted during VDD undervoltage or MR activation |
| WDO (Pin 8) | Watchdog Output | Active-low open-drain output asserting on watchdog timeout; used to reset or interrupt host processor |
Key Features
| Feature | Design Value |
|---|---|
| Fixed 200-ms reset delay | Eliminates need for external RC timing network, reducing BOM count and layout area |
| Integrated 4.55-V threshold | Matches standard 5-V logic supply with ±2% accuracy over temperature, ensuring robust brownout detection |
| Dual supervision capability | Simultaneous monitoring of main VDD and auxiliary PFI rail enables comprehensive system power integrity coverage |
| 1.6-s watchdog timeout | Provides sufficient time for complex MCU boot sequences while guaranteeing recovery from lockup |
| 50 µA max quiescent current | Supports always-on supervision in energy-constrained applications such as portable instrumentation and remote sensors |
Applications
| Industrial Programmable Logic Controllers | Automotive Body Control Modules |
|---|---|
Use Scenario: Supervising 5-V MCU and 12-V actuator supply in PLC backplane modules operating in harsh factory environments. IC Role / Device Role / Timing Role: TPS3705-50D provides primary VDD reset, secondary 12-V power-fail warning via PFI divider, and watchdog-triggered safe state entry on firmware crash. Use Value: Prevents erratic I/O behavior during brownout by holding MCU in reset until both supplies stabilize, and enables graceful shutdown on auxiliary rail collapse. | Use Scenario: Monitoring 5-V infotainment SoC supply and 12-V vehicle battery in BCMs where low-power standby and fail-safe restart are critical. IC Role / Device Role / Timing Role: TPS3705-50D asserts RESET during cold-crank voltage dip, uses PFO to flag battery sag below 11.5 V, and resets SoC via WDO if firmware hangs during CAN message processing. Use Value: Ensures deterministic power sequencing and fault recovery without adding discrete comparators or timers, meeting ISO 16750-2 transient immunity requirements. |
| Portable Medical Instrumentation | Wireless Sensor Node Gateways |
Use Scenario: Supervising 5-V USB-powered microcontroller and backup coin-cell supply in handheld diagnostic devices with battery-fail alerting. IC Role / Device Role / Timing Role: TPS3705-50D monitors main 5-V rail for USB disconnect events and uses PFI to detect coin-cell voltage decay below 2.5 V via resistor divider. Use Value: Enables early low-battery warning before data loss occurs, while 50 µA supply current extends operational life in sleep mode. | Use Scenario: Providing reset and watchdog supervision for 5-V LoRaWAN gateway MCU alongside 3.3-V RF transceiver supply monitoring. IC Role / Device Role / Timing Role: TPS3705-50D supervises 5-V core supply and uses PFI to monitor 3.3-V rail (via scaled divider) for RF subsystem faults. Use Value: Guarantees clean boot after power cycle and detects RF transceiver supply collapse before corrupted packet transmission occurs. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar voltage supervision applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX706RCSA+ | 5-V threshold (4.65 V), no watchdog timer, 200-ms reset delay, 12 µA supply current | Lacks WDI/WDO functionality; suitable only for basic reset supervision without system-level fault recovery | Select when watchdog capability is unnecessary and ultra-low quiescent current is prioritized over dual-rail monitoring |
| TPS3823-50DBVR | 5-V threshold (4.65 V), no PFI/PFO, 200-ms delay, 15 µA supply current, SOT-23-5 package | Single-supply supervision only; missing power-fail comparator and watchdog, but smaller footprint | Choose for space-constrained designs where only main rail monitoring is required and auxiliary supply detection is handled externally |
Compared with MAX706RCSA+ and TPS3823-50DBVR, TPS3705-50D uniquely integrates VDD supervision, PFI-based auxiliary rail monitoring, and watchdog timer in one SOIC-8 device-enabling consolidated fault detection and recovery without increasing board area or component count.
Availability
TPS3705-50D is available at Aetrix Electronics and suitable for industrial programmable controllers, automotive body electronics, portable medical instrumentation, and wireless sensor gateways requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for TPS3705-50D 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 delivering analog and embedded processing solutions for industrial, automotive, and personal electronics markets.
The TPS370x family was designed specifically for microprocessor-based systems needing simultaneous power-on reset, supply voltage supervision, power-fail warning, and watchdog functionality-all in a single compact IC.
FAQ
What is the exact VIT– threshold voltage for TPS3705-50D and how is it specified?
The TPS3705-50D has a guaranteed negative-going input threshold voltage (VIT–) of 4.55 V with ±2% tolerance over −40°C to 85°C. This value is factory-trimmed and tested per TI SLVS184F Rev F, ensuring precise 5-V rail supervision without external calibration. The 70 mV hysteresis prevents chatter during marginal supply conditions.
Does TPS3705-50D require an external capacitor for reset timing?
No, TPS3705-50D does not require an external capacitor for its 200-ms power-on reset delay. The timing is fully internal and factory-calibrated, eliminating component count, layout sensitivity, and temperature drift associated with RC networks. This simplifies design and improves reliability in high-vibration or wide-temperature environments.
How does the watchdog function operate in TPS3705-50D?
The TPS3705-50D watchdog timer times out after 1.6 s (typical) if no edge transition occurs on WDI. A rising or falling edge resets the timer. If timeout occurs, WDO asserts low to signal host MCU failure. Leaving WDI unconnected disables the watchdog. This provides deterministic recovery from software lockups without firmware intervention.
Can TPS3705-50D monitor a 12-V supply, and how is this implemented?
Yes, TPS3705-50D can monitor a 12-V supply using the PFI input with an external resistor divider. For example, a 910-kΩ/120-kΩ divider scales 12 V to ~1.25 V at PFI-matching the device's 1.25-V PFI threshold. PFO then asserts low when the 12-V rail drops below ~11.5 V, enabling power-fail warning without additional comparators.
What package options are available for TPS3705-50D and what are their key mechanical differences?
TPS3705-50D is offered in 8-pin SOIC (D package), measuring 3.90 mm × 4.90 mm. It is not available in MSOP-PowerPAD for this variant (TPS3705-50DGN is the MSOP version). The SOIC package uses gull-wing leads, supports standard reflow profiles, and provides adequate thermal dissipation (725 mW at 25°C) for supervisory IC power levels.
TPS3705-50D 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:
- Push-Pull, Totem Pole
- Reset:
- Active Low
- Reset Timeout:
- 140ms Minimum
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
TPS3705-50D FAQ
1.How can I place an order for TPS3705-50D through Aetrix?
Please submit a Request for Quotation (RFQ) for TPS3705-50D 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 TPS3705-50D reliable?
The price and inventory of TPS3705-50D are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TPS3705-50D is usually 5 days.
3.What payment methods are accepted for TPS3705-50D?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TPS3705-50D transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TPS3705-50D?
TPS3705-50D orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TPS3705-50D 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 TPS3705-50D?
For technical support, including TPS3705-50D datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TPS3705-50D requirements.
6.How does Aetrix verify that TPS3705-50D is sourced from the original manufacturer or authorized distributors?
All TPS3705-50D 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 TPS3705-50D meets industry standards.
7.What is the process for return or replacement of TPS3705-50D?
All TPS3705-50D units undergo pre-shipment inspection (PSI). If there is an issue with TPS3705-50D, 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 TPS3705-50D part is unused and in its original packaging.
Return procedure for TPS3705-50D:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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