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onsemi CAT825RTDI-GT3
- Part No.:
- CAT825RTDI-GT3
- Manufacturer:
- onsemi
- Category:
- Supervisors
- Package:
- SOT-23-5 Thin, TSOT-23-5
- Datasheet:
-
CAT825RTDI-GT3.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL TSOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:4,160
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Product details
Overview
CAT825RTDI-GT3 from onsemi is a system supervisory voltage reset IC with watchdog timer and manual reset input, designed for brownout detection and power-on reset in microcontroller-based systems. It features a 2.63 V reset threshold (±15 mV), 140–400 ms reset timeout, 1.12–3.20 s watchdog timeout, TSOT-23-5 package, and operates from −40°C to +85°C.
For engineers reviewing the CAT825RTDI-GT3 datasheet, pinout, applications, or equivalent options, this page delivers verified electrical specs, functional role in power sequencing, watchdog timing behavior, MR debouncing characteristics, and validated alternatives for 2.6 V–3.0 V supply monitoring designs.
Technical Context
The CAT825RTDI-GT3 implements a precision bandgap reference with 40 ppm/°C tempco and internal hysteresis (5 mV) to ensure stable brownout detection across temperature. Its digital delay block enforces a minimum 140 ms reset assertion after VCC exceeds VRST, independent of MR or WDI activity.
Watchdog functionality resets the system if the WDI input fails to toggle within 1.12–3.20 s; the input accepts CMOS-level signals (VIH = 0.7×VCC, VIL = 0.3×VCC) and supports tri-state disable. The MR input includes internal 52 kΩ pull-up and 100 ns noise immunity, with 5 µs delay from MR low to RESET assertion.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 2.63 V (min 2.55 V, max 2.70 V) - sets brownout detection point for 2.6 V–3.0 V logic domains |
| Reset Timeout | 140–400 ms - ensures sufficient stabilization time for MCU core and peripherals post-power-up |
| Watchdog Timeout | 1.12–3.20 s - provides configurable supervision window for firmware heartbeat monitoring |
| Supply Current | 4–12 µA - enables ultra-low-power operation in battery-backed or energy-constrained systems |
| Operating Temp | −40°C to +85°C - supports industrial and automotive under-hood ambient conditions |
| Reset Output Type | CMOS push-pull active-low - drives standard MCU reset inputs without external pull-up |
| MR Pull-up | 52 kΩ internal - allows direct connection to momentary switch without external resistor |
Pinout & Package
Package: TSOT-23-5 (Case 419AE), 2.90 mm × 1.60 mm × 0.95 mm, RoHS-compliant NiPdAu finish.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VCC | Power supply input | Accepts 1.2–5.5 V; powers internal reference, timer, and output stage |
| WDI | Watchdog timer input | Edge-sensitive; timeout triggered if no transition occurs within watchdog period |
| RESET | Active-low reset output | CMOS push-pull; sinks 1.2 mA at 0.3 V, sources 0.8×VCC when high |
| GND | Ground reference | Return path for all internal circuits and output current |
| MR | Manual reset input | Active-low; internally pulled up to VCC via 52 kΩ; debounced with 100 ns noise immunity |
Key Features
| Feature | Design Value |
|---|---|
| Programmable reset threshold | 2.63 V variant optimized for 2.6 V–3.0 V I/O domains and low-voltage MCUs |
| Integrated watchdog timer | Self-contained 1.12–3.20 s timeout with no external components required |
| Manual reset with debounce | Internal 52 kΩ pull-up and 100 ns noise filtering eliminate need for RC network |
| Push-pull RESET output | Eliminates external pull-up resistor and ensures valid logic levels down to VCC = 1.0 V |
| Wide supply range | Operates from 1.2 V to 5.5 V, enabling use across multiple rail voltages in same design |
Applications
| Industrial PLC Controller | Medical Diagnostic Handheld |
|---|---|
Use Scenario: Power cycling during field firmware updates in programmable logic controllers with isolated 24 V DC input and 3.3 V/2.6 V logic rails. IC Role / Device Role / Timing Role: Supervises 2.6 V microcontroller supply and asserts RESET until VCC stabilizes above 2.63 V; triggers watchdog if communication stack hangs. Use Value: Prevents corrupted register states during brownout by enforcing ≥140 ms reset hold time and validating firmware liveness via WDI strobing. |
Use Scenario: Battery-powered ultrasound probe requiring reliable cold-start and fault recovery without user intervention. IC Role / Device Role / Timing Role: Monitors 2.6 V analog front-end and ARM Cortex-M0+ core supply; initiates hard reset on undervoltage or missed watchdog pulse. Use Value: Ensures deterministic boot sequence and eliminates silent lockup by combining precise 2.63 V threshold with 1.6 s watchdog window. |
| Automotive Body Control Module | Smart Energy Meter |
Use Scenario: 12 V vehicle battery with wide transients powering a LIN-connected BCM using 2.6 V CAN transceiver and MCU. IC Role / Device Role / Timing Role: Detects battery sag below 2.63 V and holds RESET active for ≥140 ms to prevent partial initialization; MR pin tied to service mode button. Use Value: Guarantees full hardware reset before MCU executes bootloader, avoiding inconsistent peripheral configuration after load dump events. |
Use Scenario: Revenue-grade meter with tamper detection, real-time clock, and isolated RS-485 interface operating from 3.3 V rail derived from AC/DC converter. IC Role / Device Role / Timing Role: Supervises 2.6 V RTC backup domain and main 3.3 V processor supply; uses WDI to verify metering firmware execution loop. Use Value: Maintains data integrity during grid fluctuations by asserting RESET before VCC drops below 2.55 V and restarting firmware via watchdog timeout. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar voltage supervisor with watchdog applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX823TRD3-T | 2.63 V reset threshold, 140 ms timeout, no watchdog timer | Lacks WDI functionality; requires external circuitry for firmware supervision | Select when watchdog capability is unnecessary and cost minimization is critical |
| TPS3808G125DBVR | 2.625 V threshold, 200 ms timeout, adjustable watchdog (1.25 s default), higher ICC (12 µA typical) | Offers adjustable watchdog via external capacitor; tighter threshold tolerance (±0.5%) | Choose when fine-grained watchdog tuning or improved accuracy justifies higher quiescent current |
Compared with CAT825RTDI-GT3, MAX823TRD3-T omits watchdog supervision entirely, while TPS3808G125DBVR adds capacitor-adjustable timeout and ±0.5% threshold accuracy at the cost of 3× higher supply current - making CAT825RTDI-GT3 optimal for fixed-timing, ultra-low-power 2.6 V brownout detection with integrated WDI.
Availability
CAT825RTDI-GT3 is available at Aetrix Electronics and suitable for industrial control systems, portable medical devices, automotive body electronics, and smart metering applications requiring stable component supply and long-term lifecycle support.
Supply support for CAT825RTDI-GT3 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
onsemi is a global semiconductor supplier delivering energy-efficient, intelligent power and sensing solutions for automotive, industrial, cloud, medical, and IoT applications.
The CAT82x family delivers compact, low-power voltage supervisors with integrated watchdog and manual reset - engineered specifically for robust power sequencing and fault recovery in resource-constrained embedded systems.
FAQ
What is the exact reset threshold voltage of CAT825RTDI-GT3 and how does it vary with temperature?
The CAT825RTDI-GT3 has a nominal reset threshold of 2.63 V, with guaranteed min/max values of 2.55 V and 2.70 V over −40°C to +85°C. Its temperature coefficient is 40 ppm/°C, meaning threshold drift is ≤±1.2 mV per 10°C change - ensuring stable brownout detection across industrial temperature ranges without external calibration.
Does CAT825RTDI-GT3 support operation below 2.0 V supply voltage?
No. CAT825RTDI-GT3 requires VCC ≥1.2 V to operate across its full temperature range (−40°C to +85°C), and ≥1.0 V only at 0°C to +70°C. Below 1.2 V, internal reference and timing circuits cannot guarantee specified reset behavior - the device is not rated for sub-1.2 V operation in industrial environments.
How does the manual reset (MR) input behave when connected to a microcontroller GPIO instead of a pushbutton?
When driven by a microcontroller GPIO, the MR input of CAT825RTDI-GT3 must be actively pulled low (≤0.3×VCC) for ≥1 µs to trigger reset; the internal 52 kΩ pull-up ensures release defaults to high. No external resistor is needed, and the 100 ns noise immunity prevents false triggering from GPIO switching transients.
Can CAT825RTDI-GT3's watchdog timer be disabled without modifying the PCB layout?
Yes. The CAT825RTDI-GT3 watchdog can be disabled by leaving the WDI pin floating (tri-stated) - the internal circuitry detects open-circuit condition and disables timeout supervision. No solder jumper or external component is required, enabling field firmware updates without hardware changes.
Is CAT825RTDI-GT3 pin-compatible with other members of the CAT82x family such as CAT823RTDI-GT3?
Yes. CAT825RTDI-GT3 shares identical TSOT-23-5 pinout and function mapping with CAT823RTDI-GT3 and CAT824 variants - VCC, WDI, RESET, GND, and MR pins occupy the same positions and perform identical roles, enabling drop-in replacement within the same voltage threshold grade.
CAT825RTDI-GT3 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- SOT-23-5 Thin, TSOT-23-5
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Programmable:
- Not Verified
- Type:
- Simple Reset/Power-On Reset
- Number of Voltages Monitored:
- 1
- Voltage - Threshold:
- 2.63V
- Output:
- Push-Pull, Totem Pole
- Reset:
- Active High/Active Low
- Reset Timeout:
- 140ms Minimum
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- TSOT-23-5
CAT825RTDI-GT3 FAQ
1.How can I place an order for CAT825RTDI-GT3 through Aetrix?
Please submit a Request for Quotation (RFQ) for CAT825RTDI-GT3 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 CAT825RTDI-GT3 reliable?
The price and inventory of CAT825RTDI-GT3 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for CAT825RTDI-GT3 is usually 5 days.
3.What payment methods are accepted for CAT825RTDI-GT3?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for CAT825RTDI-GT3 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for CAT825RTDI-GT3?
CAT825RTDI-GT3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your CAT825RTDI-GT3 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 CAT825RTDI-GT3?
For technical support, including CAT825RTDI-GT3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your CAT825RTDI-GT3 requirements.
6.How does Aetrix verify that CAT825RTDI-GT3 is sourced from the original manufacturer or authorized distributors?
All CAT825RTDI-GT3 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 CAT825RTDI-GT3 meets industry standards.
7.What is the process for return or replacement of CAT825RTDI-GT3?
All CAT825RTDI-GT3 units undergo pre-shipment inspection (PSI). If there is an issue with CAT825RTDI-GT3, 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 CAT825RTDI-GT3 part is unused and in its original packaging.
Return procedure for CAT825RTDI-GT3:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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