Specifications
| Type | Description |
|---|---|
| Part Number | TPS3851 |
| Manufacturer | Texas Instruments |
| Product Type | LDO Regulator |
| Category | Power Management |
| Input voltage range | 1.6 to 6.5 V; VDD supply pin |
| Undervoltage threshold accuracy | ±0.8%; -40°C to +125°C, entering RESET |
| Supply current | 10 µA typ, 19 µA max; TA = 25°C typical; VITN + VHYST <= VDD <= 6.5 V |
| Operating junction temperature range | -40°C to +125°C; recommended operating conditions |
| Package | 8-pin VSON, 3.00 mm x 3.00 mm; DRB package, nominal body size |
| Output type | Open-drain RESET and WDO outputs; external pullup resistor required |
| RESET/WDO pullup resistor | 1 kΩ min, 10 kΩ typ, 100 kΩ max; recommended operating conditions |
| SET1 pin voltage | 0 to 6.5 V; recommended operating conditions |
| Watchdog timing capacitor | 0.1 to 1000 nF; CWD pin, recommended operating conditions |
| CWD pullup resistor to VDD | 9 kΩ min, 10 kΩ typ, 11 kΩ max; recommended operating conditions |
| RESET pin current | 10 mA max; recommended operating conditions |
| Watchdog output current | 10 mA max; recommended operating conditions |
| Power-on reset voltage | 0.8 V typ; IRESET = 15 µA, VOL(max) = 0.25 V |
| Undervoltage lockout voltage | 1.35 V typ; when VDD falls below VUVLO, RESET is driven low |
| Hysteresis voltage | 0.2% min, 0.5% typ, 0.8% max; VDD rising |
| MR internal pullup current | 500 nA min, 620 nA typ, 700 nA max; VMR = 0 V |
| CWD charge current | 347 nA min, 375 nA typ, 403 nA max; CWD = 0.5 V |
| CWD threshold voltage | 1.196 V min, 1.21 V typ, 1.224 V max; watchdog function |
| RESET/WDO output low voltage | 0.4 V max; VDD = 5 V, ISINK = 3 mA |
| RESET/WDO open-drain output leakage current | 1 µA max; VDD = VITN + VHYST, VRESET = VWDO = 6.5 V |
| MR/SET1 low-level input voltage | 0.25 V max; logic input low threshold |
| MR/SET1 high-level input voltage | 0.8 V min; logic input high threshold |
| WDI low-level input voltage | 0.3 x VDD max; watchdog input low threshold |
| WDI high-level input voltage | 0.8 x VDD min; watchdog input high threshold |
| Reset timeout period | 170 ms min, 200 ms nom, 230 ms max; VITN + VHYST <= VDD <= 6.5 V, -40°C <= TA <= 125°C |
| VDD to RESET delay, rising condition | 35 µs typ; VDD = VITN + VHYST + 2.5% |
| VDD to RESET delay, falling condition | 17 µs typ; VDD = VITN - 2.5% |
| MR to RESET delay | 200 ns typ; manual reset asserted |
| Watchdog timeout, CWD NC | 1360 ms min, 1600 ms nom, 1840 ms max; CWD = NC, SET1 = 1 |
| Watchdog timeout, CWD pullup | 170 ms min, 200 ms nom, 230 ms max; CWD = 10 kΩ to VDD, SET1 = 1 |
| Watchdog disabled mode | Watchdog disabled; CWD = NC, SET1 = 0 or CWD = 10 kΩ to VDD, SET1 = 0 |
| WDI setup time after watchdog enabled | 150 µs typ; time required for device to respond to WDI changes after being enabled |
| Minimum WDI pulse duration | 50 ns typ; watchdog input pulse |
| WDI to WDO delay | 50 ns typ; watchdog input transition to watchdog output |
| CWD pin evaluation period | 381 µs typ; timing requirement |
| Minimum MR/SET1 pulse duration | 1 µs typ; timing requirement |
| Startup delay | 300 µs typ; during power-on, VDD must be at least 1.6 V before RESET correlates with VDD |
| Absolute maximum VDD | -0.3 to 7 V; supply voltage range stress rating |
| Absolute maximum RESET/WDO voltage | -0.3 to 7 V; output voltage range stress rating |
| Absolute maximum SET1/WDI/MR voltage | -0.3 to 7 V; input voltage stress rating |
| Absolute maximum CWD voltage | -0.3 to VDD + 0.3 V; limited to VDD + 0.3 V or 7.0 V, whichever is smaller |
| ESD HBM rating | ±4000 V; human-body model, ANSI/ESDA/JEDEC JS-001 |
| ESD CDM rating | ±1000 V; charged-device model, JEDEC JESD22-C101 |
| Junction-to-ambient thermal resistance | 50.7 °C/W; DRB VSON-8 package |
| Junction-to-case bottom thermal resistance | 7.1 °C/W; DRB VSON-8 package |
| Datasheet Status | request_only |
Product Overview
The TPS3851 is a Texas Instruments precision voltage supervisor with watchdog for Power_Management designs. It monitors the VDD supply pin across a 1.6 to 6.5 V input range and provides ±0.8% undervoltage threshold accuracy over -40°C to +125°C when entering RESET. Typical supply current is 10 µA, with a 19 µA maximum under the specified VDD condition.
The device uses open-drain RESET and WDO outputs, requiring an external pullup resistor. Recommended RESET/WDO pullup values are 1 kΩ minimum, 10 kΩ typical, and 100 kΩ maximum. RESET and watchdog output current are each specified up to 10 mA maximum, and RESET/WDO output low voltage is 0.4 V maximum at VDD = 5 V and ISINK = 3 mA.
Watchdog timing can use the CWD pin, with a recommended watchdog timing capacitor range of 0.1 to 1000 nF. Watchdog timeout options include 1600 ms nominal with CWD not connected and SET1 high, or 200 ms nominal with CWD pulled to VDD through 10 kΩ and SET1 high. The package is an 8-pin VSON DRB with a 3.00 mm x 3.00 mm nominal body size.
Key Features
- 1.6 to 6.5 V VDD supply input range
- ±0.8% undervoltage threshold accuracy over temperature
- 10 µA typical supply current at 25°C
- Open-drain RESET and WDO outputs
- External RESET/WDO pullup resistor required
- 200 ms nominal reset timeout period
- Selectable 1600 ms or 200 ms watchdog timeout
- Watchdog disabled mode through SET1 and CWD states
- 0.1 to 1000 nF CWD timing capacitor range
- -40°C to +125°C operating junction temperature
- 8-pin 3.00 mm x 3.00 mm VSON package
Typical Applications
- Processor reset supervision
- Power rail undervoltage monitoring
- Watchdog timer supervision
- Manual reset input circuits
- Low-current power-management systems
- Compact VSON-based assemblies
- Open-drain reset output designs
- Wide-temperature electronic systems
Procurement Notes
When requesting a quote for TPS3851, buyers should confirm the manufacturer, package or case, required quantity, target date code, compliance documents, packing method, destination country and expected delivery schedule.
If alternatives are acceptable, buyers should share the approved vendor list, required electrical or optical limits, package constraints and qualification requirements. Any alternative part should be reviewed by the buyer's engineering team before production use.
For power IC and power device sourcing, voltage rating, current rating, power dissipation, package thermal performance, protection features, qualification grade and application conditions should be reviewed before approval.
FAQ
What supply voltage range does the TPS3851 support?
The TPS3851 supports a VDD supply input range from 1.6 to 6.5 V. During power-on, VDD must be at least 1.6 V before RESET correlates with VDD, and undervoltage lockout drives RESET low when VDD falls below the specified UVLO voltage.
What output type is used for RESET and WDO?
RESET and WDO are open-drain outputs, so an external pullup resistor is required. The recommended pullup range is 1 kΩ minimum, 10 kΩ typical, and 100 kΩ maximum, with RESET and watchdog output current specified up to 10 mA maximum.
How is the watchdog timeout configured on TPS3851?
The watchdog timeout depends on the CWD and SET1 conditions. With CWD not connected and SET1 high, the timeout is 1600 ms nominal. With CWD connected through 10 kΩ to VDD and SET1 high, the timeout is 200 ms nominal.
What package is specified for the TPS3851?
The TPS3851 is specified in an 8-pin VSON DRB package with a nominal 3.00 mm x 3.00 mm body size. Thermal data includes 50.7 °C/W junction-to-ambient resistance and 7.1 °C/W junction-to-case bottom resistance for the DRB package.
Technical Review & Sourcing Note
Prepared by LDeepAI Component Sourcing Team. Reviewed for RFQ, documentation and alternative sourcing use. Last updated: July 7, 2026.
This page is based on manufacturer datasheet information and LDeepAI sourcing review. Specifications should be verified against the official manufacturer datasheet before final procurement or design approval. Final electrical, optical and reliability approval should be confirmed by the buyer's engineering team.