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Texas Instruments UCC2946PWG4
- Part No.:
- UCC2946PWG4
- Manufacturer:
- Texas Instruments
- Category:
- Supervisors
- Package:
- 8-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
UCC2946PWG4.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 8TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,570
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Product details
Overview
UCC2946PWG4 from Texas Instruments is a microprocessor supervisor IC with integrated watchdog timer, programmable reset threshold (1.235 V ±2%), programmable reset period (140–320 ms), and programmable watchdog period (0.96–2.56 s). It operates from 2.1 V to 5.5 V, draws ≤18 µA supply current, and asserts valid reset down to VDD = 1 V - used in industrial embedded systems requiring reliable power-on and fault recovery.
For engineers reviewing the UCC2946PWG4 datasheet, UCC2946PWG4 pinout, UCC2946PWG4 application, or UCC2946PWG4 equivalent, key selection criteria include its wide temperature range (–40°C to +95°C), glitch-immune reset detection, independent RES/WDO outputs, and external capacitor-based timing programming for both reset and watchdog functions.
Technical Context
The UCC2946PWG4 implements dual independent timing blocks: a precision 400 nA current source charges CRP to set reset period (TRP = 3.125 × CRP), and a separate 25 nA source charges CWP to set watchdog period (TWP = 25 × CWP). Both thresholds reference an internal 1.235 V bandgap.
Reset assertion is voltage- and time-conditioned: VDD must exceed the programmed RTH threshold *and* remain stable for TRP; transient dips below threshold are ignored unless exceeding amplitude/duration limits per Figure 1. Watchdog monitoring occurs only after reset deassertion and disables during active reset.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Operating Voltage | 2.1 V to 5.5 V - supports 3.3 V and 5 V logic rails without level-shifting |
| Reset Threshold Accuracy | ±2% at 1.235 V - enables precise undervoltage detection for 3.3 V or 2.5 V core supplies |
| Supply Current | ≤18 µA max - suitable for battery-backed or low-power always-on supervision |
| Reset Valid Down to | VDD = 1 V - guarantees functional reset assertion even during brownout collapse |
| Reset Period Range | 140 ms to 320 ms (with 64 nF RP capacitor) - configurable for diverse processor boot timing |
| Watchdog Period Range | 0.96 s to 2.56 s (with 64 nF WP capacitor) - accommodates slow or fast firmware polling intervals |
| Temperature Range | –40°C to +95°C - qualified for industrial ambient operation, not automotive or military |
Pinout & Package
UCC2946PWG4 is housed in an 8-pin TSSOP (PW) package with 0.65 mm pitch, optimized for compact PCB layouts and thermal performance in industrial enclosures.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| GND (Pin 1) | Ground reference | Return path for all internal analog and digital circuitry; requires low-impedance connection to system ground plane |
| RTH (Pin 2) | Reset threshold sense input | High-impedance input comparing external resistor divider voltage to 1.235 V reference; sets reset trip point |
| RES (Pin 3) | Active-low reset output | Open-drain output asserting low during power-up, brownout, or voltage glitch; pulls high via external pull-up |
| RP (Pin 4) | Reset period timing capacitor | Connects to precision 400 nA current source; sets reset timeout duration (TRP = 3.125 × CRP) |
| WDI (Pin 5) | Watchdog input | Edge-sensitive input requiring toggle within watchdog period to prevent WDO assertion |
| WP (Pin 6) | Watchdog period timing capacitor | Connects to precision 25 nA current source; sets watchdog timeout (TWP = 25 × CWP) |
| VDD (Pin 8) | Power supply input | Accepts 2.1–5.5 V; powers internal circuitry and provides reference for WDI logic thresholds |
| WDO (Pin 7) | Active-low watchdog output | Open-drain output asserted low if WDI is not toggled within TWP; independent of RES state |
Key Features
| Feature | Design Value |
|---|---|
| Fully programmable reset threshold | Set via external R1/R2 divider on RTH pin - supports monitoring of any rail (1.8 V, 2.5 V, 3.3 V, 5 V) |
| Glitch-immune reset detection | Ignores transients <100 mV/120 µs - prevents spurious resets from switching noise or ESD |
| Independent RES and WDO outputs | Enables flexible reset architecture: either output can drive MCU reset, or combined via OR gate |
| Low quiescent current | 18 µA max across full VDD and temperature range - extends battery life in backup-supervised systems |
| Valid reset at 1 V VDD | Ensures deterministic behavior during deep brownout - critical for safe shutdown sequencing |
Applications
| Industrial PLC Controller | Smart Energy Meter |
|---|---|
Use Scenario: Programmable logic controller operating in factory environments with variable line voltage and EMI. IC Role / Device Role / Timing Role: Supervises 3.3 V microcontroller power rail and monitors firmware liveness via WDI strobing. Use Value: Prevents runaway code execution during AC line sags using glitch-immune reset; watchdog enforces firmware health checks every 2 seconds. | Use Scenario: Revenue-grade electricity meter with tamper detection and long-term battery backup. IC Role / Device Role / Timing Role: Provides brownout reset for metrology SoC and initiates secure shutdown sequence when main supply fails. Use Value: Valid RES assertion down to 1 V ensures controlled shutdown before EEPROM corruption; 18 µA IDD minimizes battery drain during decades-long backup operation. |
| Factory Automation HMI | Industrial Gateway Router |
Use Scenario: Human-machine interface panel with ARM Cortex-M7 running real-time UI and communication stacks. IC Role / Device Role / Timing Role: Monitors 5 V system rail and feeds WDI from heartbeat timer interrupt. Use Value: Programmable 200 ms reset period matches bootloader initialization window; independent WDO allows NMI-triggered recovery without affecting peripheral reset timing. | Use Scenario: Edge gateway aggregating Modbus, CAN, and Ethernet traffic in harsh electrical environments. IC Role / Device Role / Timing Role: Supervises dual-rail power (3.3 V I/O, 1.2 V core) and detects firmware lockup in network stack threads. Use Value: Separate RP and WP capacitors enable asymmetric timing: 160 ms reset for fast boot, 2.56 s watchdog for complex protocol handshakes. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervision applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX6816EPA+ | Fixed 3.08 V reset threshold; no watchdog; 10 µA IDD; –40°C to +85°C | Lacks programmability and watchdog - suitable only for simple reset-only use cases | Select when only basic power-on reset is needed and board space permits DIP-8 package |
| TPS3808G12DBVR | Fixed 1.22 V threshold; adjustable delay (1.25 ms–10 s); no watchdog; 12 µA IDD; –40°C to +125°C | Offers wider temp range but no WDI/WDO functionality - requires external watchdog circuit | Choose for high-temp environments where watchdog is implemented separately in FPGA or software |
Compared with MAX6816EPA+ and TPS3808G12DBVR, the UCC2946PWG4 uniquely integrates fully programmable reset *and* watchdog timing in one 8-pin TSSOP, eliminating external components and enabling adaptive supervision for evolving firmware requirements.
Availability
UCC2946PWG4 is available at Aetrix Electronics and suitable for industrial PLC controllers, smart energy meters, factory HMI panels, and edge gateway routers requiring stable component supply across extended product lifecycles.
Supply support for UCC2946PWG4 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 personal electronics markets.
The UCC2946PWG4 belongs to TI's legacy microprocessor supervisor family designed specifically for robust, capacitor-programmable power monitoring and fault recovery in industrial control and instrumentation systems.
FAQ
What is the operating temperature range for the UCC2946PWG4?
The UCC2946PWG4 is rated for operation from –40°C to +95°C. This industrial-grade temperature specification ensures reliable reset and watchdog functionality in factory automation, energy infrastructure, and outdoor equipment environments where ambient temperatures exceed commercial limits. The UCC2946PWG4 datasheet confirms this range applies specifically to the UCC2946 variant, distinct from the wider –55°C to +125°C range of UCC1946 or narrower 0°C to +70°C range of UCC3946.
Can the UCC2946PWG4 monitor a 1.8 V supply rail?
Yes, the UCC2946PWG4 can monitor a 1.8 V supply rail using the RTH pin with an external resistor divider. Since the internal reference is 1.235 V, setting R1 = 453 kΩ and R2 = 1 MΩ yields a trip point of ~1.8 V (VRESET = 1.235 × (R1 + R2)/R2). The UCC2946PWG4's high-impedance RTH input and 2% threshold accuracy make it suitable for precise low-voltage rail supervision without additional level-shifting circuitry.
How does the UCC2946PWG4 handle voltage glitches on the VDD line?
The UCC2946PWG4 rejects short-duration VDD glitches using built-in hysteresis and time-based filtering. Glitches under 100 mV amplitude and 120 µs duration are ignored at the RTH pin, preventing false resets. This behavior is guaranteed by design and documented in Figure 1 of the UCC2946PWG4 datasheet. The IC only asserts RES when VDD dips below the programmed threshold for a sustained period exceeding the glitch immunity window.
Is the UCC2946PWG4 pin-compatible with UCC3946 or UCC1946?
Yes, the UCC2946PWG4 shares identical pinout and package (8-pin TSSOP) with UCC1946 and UCC3946, as confirmed by the shared connection diagram and block diagram in the SLUS247B datasheet. However, temperature ratings differ: UCC2946PWG4 is rated –40°C to +95°C, while UCC3946 is 0°C to +70°C and UCC1946 is –55°C to +125°C. Electrical parameters like minimum VDD (2.1 V vs. 2.0 V) and supply current also vary slightly between variants.
What capacitor types are recommended for RP and WP pins on the UCC2946PWG4?
NP0/C0G ceramic capacitors are recommended for both RP and WP pins on the UCC2946PWG4 due to their low leakage, tight tolerance, and minimal voltage/temperature drift. The UCC2946PWG4 datasheet specifies that CRP and CWP are charged by precision 400 nA and 25 nA current sources respectively; high-leakage dielectrics (e.g., X7R, Y5V) introduce timing errors. For a 200 ms reset period, a 64 nF NP0 capacitor on RP yields nominal timing per TRP = 3.125 × CRP.
UCC2946PWG4 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 8-TSSOP (0.173", 4.40mm Width)
- Packaging:
- Tray
- Product Status:
- Discontinued at Digi-Key
- Programmable:
- Not Verified
- Type:
- Simple Reset/Power-On Reset
- Number of Voltages Monitored:
- 1
- Voltage - Threshold:
- Adjustable/Selectable
- 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-TSSOP
UCC2946PWG4 FAQ
1.How can I place an order for UCC2946PWG4 through Aetrix?
Please submit a Request for Quotation (RFQ) for UCC2946PWG4 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 UCC2946PWG4 reliable?
The price and inventory of UCC2946PWG4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for UCC2946PWG4 is usually 5 days.
3.What payment methods are accepted for UCC2946PWG4?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for UCC2946PWG4 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for UCC2946PWG4?
UCC2946PWG4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your UCC2946PWG4 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 UCC2946PWG4?
For technical support, including UCC2946PWG4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your UCC2946PWG4 requirements.
6.How does Aetrix verify that UCC2946PWG4 is sourced from the original manufacturer or authorized distributors?
All UCC2946PWG4 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 UCC2946PWG4 meets industry standards.
7.What is the process for return or replacement of UCC2946PWG4?
All UCC2946PWG4 units undergo pre-shipment inspection (PSI). If there is an issue with UCC2946PWG4, 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 UCC2946PWG4 part is unused and in its original packaging.
Return procedure for UCC2946PWG4:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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