TPS3806 Dual Voltage Detector with Adjustable Hysteresis

The TPS3806 integrates two independent voltage monitors for battery-voltage supervision. During power-up, when the supply voltage V_DD and the LSENSE input voltage exceed 0.8 V, the RESET and RSTSENSE outputs are initialized. The monitor circuitry then compares V_DD and LSENSE to their respective thresholds; if either input falls below its threshold, the corresponding reset output is asserted. When V_DD or LSENSE rises above its threshold, the corresponding reset output is released. The device provides a fixed V_DD threshold set by an internal divider and an adjustable LSENSE input. An HSENSE input sets the upper threshold for LSENSE to allow a wider adjustable hysteresis window.

Key Features

• Dual voltage detectors with adjustable hysteresis: 3.3 V/adjustable and 2 V/adjustable options
• Ensures reset during power-up at V_DD = 0.8 V
• Supply current: typical 3 μA at V_DD = 3.3 V
• Independent open-drain reset outputs
• Operating temperature range: -40°C to 85°C
• 6-pin SOT-23 package

Parameters

See figure above for functional block diagram and pin connections.

1. Product Overview

• Product names: TPS3806J20, TPS3806I33
• Function: Dual voltage detectors with adjustable hysteresis for battery-voltage monitoring
• Highlights:
  • Two integrated independent voltage detectors
  • Adjustable hysteresis
  • Independent open-drain reset outputs
  • Low supply current (typical 3 μA)
  • Operating temperature range: -40°C to +85°C
  • 6-pin SOT-23 package

2. Electrical Characteristics

• Supply voltage: 1.3 V to 6 V
• Low-level output voltage: V_OL = 0.3 V (typical)
• Threshold voltages:
  • TPS3806J20: fixed V_DD threshold 1.8 V
  • TPS3806I33: fixed V_DD threshold 3.0 V
  • LSENSE input threshold adjustable, typical 1.207 V
• Hysteresis voltage: set by HSENSE input, range approximately 60 mV to 90 mV
• Supply current: typical 3 μA (V_DD = 3.3 V)

3. Functional Description

• Power-up reset: When the supply voltage V_DD or the LSENSE input exceeds 0.8 V during power-up, the RESET and RSTSENSE outputs are initialized.
• Voltage monitoring: V_DD and LSENSE inputs are continuously monitored. If either input drops below its threshold, the corresponding reset output remains asserted.
• Hysteresis: HSENSE sets the hysteresis window between the upper and lower thresholds to prevent reset chatter due to voltage fluctuations.
• Reset release: When V_DD or LSENSE rises above its threshold, the corresponding reset output is released.

4. Package and Marking

• Package: 6-pin SOT-23
• Marking examples:
  • TPS3806J20DB VR: indicates J20 version in 3000-unit tape-and-reel packaging
  • TPS3806I33DBVT: indicates I33 version in 250-unit small reel packaging

5. Applications

• Battery-powered devices
• Systems requiring dual-voltage monitoring
• Embedded systems that require reset supervision

6. Typical Characteristics

• Typical curves are provided for supply current versus supply voltage, low-level output voltage versus low-level output current, and other typical characteristics.
• Normalized input threshold versus ambient temperature is shown in the characteristic plots.

7. Usage Notes

• To ensure optimal threshold stability, place a 0.1 μF ceramic bypass capacitor near the supply pin.
• Use appropriate electrostatic discharge (ESD) precautions when handling the integrated circuit.