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Texas Instruments UCC2946PW
- Part No.:
- UCC2946PW
- Manufacturer:
- Texas Instruments
- Category:
- Supervisors
- Package:
- 8-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
UCC2946PW.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 8TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:660
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Product details
Overview
UCC2946PW 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 = 1.1 V - used in industrial embedded systems requiring reliable power-on and fault recovery.
For engineers reviewing the UCC2946PW datasheet, UCC2946PW pinout, UCC2946PW application, or UCC2946PW equivalent, key selection criteria include its −40°C to +95°C operating temperature range, TSSOP-8 package, independent RES/WDO outputs, and external capacitor-based timing programming for both reset and watchdog functions.
Technical Context
The UCC2946PW implements dual independent timing blocks: a precision 400 nA current source charges external capacitors at RP (reset period) and WP (watchdog period), enabling user-defined delays via CRP and CWP. Its internal 1.235 V reference compares against voltage divider input at RTH to generate reset assertion.
Reset remains active during VDD < 1.1 V and ignores transients below 100 mV overdrive for <120 µs (glitch immunity). Watchdog monitoring occurs only after reset deassertion, and WDO is disabled during active reset - ensuring clean state transitions between power-up and runtime supervision.
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 | 1.235 V ±2% - accurate trip point set by external R1/R2 divider at RTH pin |
| Supply Current | ≤18 µA - enables long-term battery-backed operation in low-power systems |
| Reset Period | 140–320 ms (CRP = 64 nF) - programmable delay ensures stable CPU clock and memory initialization |
| Watchdog Period | 0.96–2.56 s (CWP = 64 nF) - configurable timeout for firmware health checks |
| Min Valid VDD | 1.1 V - guarantees functional reset output even during brownout conditions |
| Temperature Range | −40°C to +95°C - qualified for industrial-grade environmental operation |
Pinout & Package
UCC2946PW is housed in an 8-pin TSSOP (PW) package - 3.0 mm × 4.4 mm, 0.65 mm pitch, surface-mount, lead-free compatible.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| GND (Pin 1) | Ground reference | Return path for all internal analog and digital circuitry; must be low-impedance |
| RTH (Pin 2) | Reset threshold sense input | High-impedance node comparing external voltage divider to 1.235 V internal reference |
| RES (Pin 3) | Active-low reset output | Open-drain output asserting low during power-up, brownout, or manual reset |
| RP (Pin 4) | Reset period timing capacitor connection | Connects to precision 400 nA current source charging CRP for programmable reset delay |
| WDI (Pin 5) | Watchdog input | Edge-sensitive input toggled by host MCU to prevent WDO assertion |
| WP (Pin 6) | Watchdog period timing capacitor connection | Connects to same 400 nA current source charging CWP for programmable watchdog timeout |
| VDD (Pin 8) | Power supply input | Supplies internal bandgap, comparators, and timing circuits; requires 0.1 µF decoupling |
| WDO (Pin 7) | Active-low watchdog output | Open-drain output asserted low if WDI not toggled within programmed watchdog period |
Key Features
| Feature | Design Value |
|---|---|
| Fully programmable reset threshold | Set via external resistor divider at RTH - supports monitoring of any rail ≥1.235 V |
| Fully programmable reset period | TRP = 3.125 × CRP (ms) - eliminates need for fixed-delay supervisors in custom designs |
| Fully programmable watchdog period | TWP = 25 × CWP (ms) - enables precise alignment with firmware execution cycles |
| Glitch-immune reset detection | Ignores transients <100 mV amplitude and <120 µs duration - prevents spurious resets on noisy rails |
| Valid reset at VDD = 1.1 V | Ensures deterministic behavior during deep brownout - critical for fail-safe shutdown sequences |
Applications
| Industrial PLC Controller | Medical Infusion Pump |
|---|---|
Use Scenario: Power-up sequencing and runtime fault detection in programmable logic controllers exposed to variable AC line conditions. IC Role / Device Role / Timing Role: Supervisor IC providing POR reset and watchdog-triggered safe-state entry upon firmware hang. Use Value: Prevents erratic I/O operation during undervoltage; 0.96–2.56 s watchdog window matches typical control loop cycle times. | Use Scenario: Safety-critical drug delivery system requiring guaranteed startup integrity and continuous software health monitoring. IC Role / Device Role / Timing Role: Dual-function supervisor asserting RES on power ramp and WDO on missed heartbeat signal from safety MCU. Use Value: 1.235 V ±2% reset threshold ensures repeatable trip point across temperature; 1.1 V minimum VDD support enables graceful shutdown before battery depletion. |
| Automotive Body Control Module | Smart Energy Meter |
Use Scenario: Microcontroller supervision in 12 V automotive subsystems subject to load dump and cold-crank transients. IC Role / Device Role / Timing Role: Reset generator and watchdog timer interfacing with 3.3 V domain MCU via level-shifted WDI/RES signals. Use Value: Glitch immunity per Figure 1 rejects >95% of typical vehicle electrical noise; −40°C to +95°C rating meets AEC-Q100 Grade 2 requirements. | Use Scenario: Tamper-resistant metering platform with long-life lithium backup and firmware integrity verification. IC Role / Device Role / Timing Role: Supervisor monitoring main 3.3 V rail and asserting WDO if metrology firmware fails to toggle WDI every 2 seconds. Use Value: 18 µA max IDD extends battery life beyond 10 years; open-drain RES/WDO outputs interface directly with MCU reset and NMI pins. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervision applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS3808G33 | Fixed 3.3 V reset threshold; no programmable watchdog; 1.8 µA IQ | Lacks independent watchdog timer and adjustable timing - suitable only for basic reset-only use cases | Select when only POR reset is needed and ultra-low quiescent current is prioritized over watchdog functionality |
| MAX6326UT29D3+ | Fixed 2.93 V reset threshold; 1.6 s watchdog; SOT-23-5 package | Smaller footprint but no RTH/RP/WP programmability - limited flexibility for multi-rail or custom timing needs | Select for space-constrained designs where fixed thresholds and compact packaging outweigh configurability |
Compared with TPS3808G33 and MAX6326UT29D3+, the UCC2946PW uniquely supports full analog programmability of both reset and watchdog timing via external capacitors and resistors - essential for systems requiring precise alignment with custom power sequencing or firmware execution windows.
Availability
UCC2946PW is available at Aetrix Electronics and suitable for industrial automation, medical device design, and automotive electronics requiring stable component supply, long-lifecycle support, and verified performance across extended temperature ranges.
Supply support for UCC2946PW 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 UCC2946PW belongs to TI's microprocessor supervisor product line - engineered specifically for robust power-on reset generation and runtime watchdog supervision in harsh environments with wide supply and temperature variation.
FAQ
What is the operating temperature range for UCC2946PW?
The UCC2946PW is rated for operation from −40°C to +95°C - qualifying it for industrial-grade applications where ambient temperatures exceed commercial limits. This range is explicitly specified in the SLUS247B datasheet for the UCC2946 variant, distinguishing it from the wider −55°C to +125°C UCC1946 and narrower 0°C to +70°C UCC3946. The TSSOP-8 (PW) package maintains thermal performance across this full range.
How is the reset threshold programmed on UCC2946PW?
The reset threshold of UCC2946PW is programmed using two external resistors (R1 and R2) forming a voltage divider connected to the RTH pin. The trip voltage follows VRESET = 1.235 V × (R1 + R2)/R2, allowing user-defined thresholds above 1.235 V. This configuration is confirmed in the "Programming the Reset Voltage" section of SLUS247B, and applies identically to UCC2946PW as part of the UCCx946 family.
Can UCC2946PW operate with a supply voltage below 2.1 V?
UCC2946PW guarantees functional reset output down to VDD = 1.1 V, though its specified operating range begins at 2.1 V. Below 2.1 V, RES remains valid and asserted low until VDD rises above the programmed threshold, but other parameters (e.g., watchdog timing accuracy) are not guaranteed. This behavior is documented in the "Minimum VDD" note and Electrical Characteristics table of SLUS247B.
What is the function of the WP pin on UCC2946PW?
The WP pin on UCC2946PW connects to an internal 400 nA precision current source that charges an external capacitor (CWP) to set the watchdog period: TWP = 25 × CWP (in ms). This pin enables full user control over watchdog timeout duration - a defining feature of the UCC2946PW versus fixed-timer alternatives. Its operation is detailed in the "Programming the Watchdog Period" section of SLUS247B.
Is UCC2946PW pin-compatible with UCC3946 or UCC1946?
Yes - UCC2946PW shares identical pinout, package dimensions, and terminal functions with UCC1946 and UCC3946 in the PW (TSSOP-8) variant, as confirmed by the shared Connection Diagram and Pin Descriptions in SLUS247B. Differences lie solely in temperature rating and absolute maximum ratings, not pin assignment or electrical interface.
UCC2946PW Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 8-TSSOP (0.173", 4.40mm Width)
- Packaging:
- Tube
- Product Status:
- Active
- 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
UCC2946PW FAQ
1.How can I place an order for UCC2946PW through Aetrix?
Please submit a Request for Quotation (RFQ) for UCC2946PW 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 UCC2946PW reliable?
The price and inventory of UCC2946PW are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for UCC2946PW is usually 5 days.
3.What payment methods are accepted for UCC2946PW?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for UCC2946PW transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for UCC2946PW?
UCC2946PW orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your UCC2946PW 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 UCC2946PW?
For technical support, including UCC2946PW datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your UCC2946PW requirements.
6.How does Aetrix verify that UCC2946PW is sourced from the original manufacturer or authorized distributors?
All UCC2946PW 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 UCC2946PW meets industry standards.
7.What is the process for return or replacement of UCC2946PW?
All UCC2946PW units undergo pre-shipment inspection (PSI). If there is an issue with UCC2946PW, 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 UCC2946PW part is unused and in its original packaging.
Return procedure for UCC2946PW:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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