Overview
The TPS3808G18DRVT, produced by Texas Instruments, is a microprocessor supervisory circuit designed to monitor system voltages and assert a RESET signal when the voltage drops below a preset threshold or when the manual reset (MR) pin is driven low. This device is part of the TPS3808 family, which offers adjustable delay times and high threshold accuracy, making it suitable for a wide range of applications, including battery-powered devices and systems requiring precise voltage monitoring.
Key Specifications
| Parameter | Test Conditions | Min | Typ | Max | Unit |
|---|---|---|---|---|---|
| VDD (Input supply range) | –40°C < TJ < 125°C | 1.7 | 6.5 | V | |
| IDD (Supply current) | VDD = 3.3 V, RESET not asserted, MR, RESET, CT open | 2.4 | 2.4 | 5 | μA |
| VOL (Low-level output voltage) | 1.3 V ≤ VDD < 1.8 V, IOL = 0.4 mA | 0.3 | V | ||
| VIT (Negative-going input threshold accuracy) | VIT ≤ 3.3 V, –40°C < TJ < 85°C | –1.5% | ±0.5% | 1.5% | % |
| VHYS (Hysteresis on VIT pin) | Fixed versions | 1% | 2.5% | % | |
| R_MR (MR Internal pullup resistance) | 70 | 90 | 90 | kΩ | |
| ISENSE (Input current at SENSE pin) | VSENSE = VIT | –25 | 25 | nA | |
| td (RESET delay time) | CT = Open | 12 | 20 | 28 | ms |
| td (RESET delay time) | CT = VDD | 180 | 300 | 420 | ms |
Key Features
- Power-on reset generator with adjustable delay time: 1.25 ms to 10 s
- Very low quiescent current: 2.4 μA typical
- High threshold accuracy: 0.5% typical for VIT ≤ 3.3 V
- Fixed threshold voltages for standard voltage rails from 0.9 V to 5 V and adjustable voltage down to 0.4 V
- Manual reset (MR) input
- Open-drain RESET output
- Temperature range: –40°C to 125°C
- Small SOT-23 and 2-mm × 2-mm WSON packages
Applications
- DSP or microcontroller applications
- Notebook and desktop computers
- PDAs and hand-held products
- Portable and battery-powered products
- FPGA and ASIC applications
Q & A
- What is the primary function of the TPS3808G18DRVT?
The primary function is to monitor system voltages and assert a RESET signal when the voltage drops below a preset threshold or when the manual reset (MR) pin is driven low.
- What is the range of the adjustable delay time for the RESET signal?
The adjustable delay time ranges from 1.25 ms to 10 s.
- What is the typical quiescent current of the TPS3808G18DRVT?
The typical quiescent current is 2.4 μA.
- What are the available package types for the TPS3808G18DRVT?
The device is available in SOT-23 and 2-mm × 2-mm WSON packages.
- What is the temperature range for the TPS3808G18DRVT?
The device is fully specified over a temperature range of –40°C to 125°C.
- How can the RESET delay time be adjusted?
The RESET delay time can be adjusted by connecting the CT pin to VDD, leaving it open, or connecting an external capacitor to set a user-defined delay.
- What is the purpose of the manual reset (MR) input?
The manual reset (MR) input allows for manual assertion of the RESET signal by driving the MR pin low.
- What is the significance of the high threshold accuracy in the TPS3808G18DRVT?
The high threshold accuracy ensures reliable and precise voltage monitoring, with a typical accuracy of 0.5% for VIT ≤ 3.3 V.
- Can the TPS3808G18DRVT monitor any voltage rail down to 0.4 V?
Yes, the TPS3808G01 can be used to monitor any voltage rail down to 0.405 V using an external resistor divider.
- How does the device handle short negative transients on the SENSE pin?
The device is relatively immune to short negative transients on the SENSE pin, with sensitivity dependent on threshold overdrive.
