Ricoh launches automotive supervisory IC with 42V/250mA LDO, voltage detector and window watchdog timer
Ricoh Europe (Netherlands) B.V. Semiconductor Support Centre has launched a compact solution combining a 42V/250mA voltage regulator, voltage detector and (window) watchdog timer for general car equipment and car accessories requiring low current consumption.
The R5114 / R5115S series consumes just 13.5µA and consist of two supervisory circuits which provide highly accurate power supply, monitor the power supply voltage with high accuracy and regulate the processor’s malfunctioning, enhancing system reliability and safety.
LDO voltage regulator
The R5114/R5115’s voltage regulator offers a highly accurate output voltage reference with +/- 0.6% accuracy at room temperature and +/- 1.6% accuracy at an operating temperature range from -40°C to 125°C.
The device’s highly accurate voltage detector is internally connected to the output voltage pin of the voltage regulator and monitors the supply voltage of the application processor and provides a reset signal after dropping below an internally fixed threshold voltage. The active reset timeout period should be long enough to reset the processor properly with the use of an external capacitor.
Watchdog timer (regular / window)
An application processor provides output pulses during normal operation and regularly resets the watchdog timer to prevent it from elapsing. In the event of a processor malfunction these pulses are too late or fail and the R5114 watchdog timer generates a reset signal to the processor after a time-out period. The advanced R5115 window watchdog timer even detects when the processor enters a random operation mode and when output pulses are too early. Various options are available to disable the watchdog timer when the processor is set to a sleep mode. For this purpose a specific inhibit input is used which is controlled by an output from the processor.
Another option is an automatic circuit monitoring the output current from the LDO regulator. As soon as the current drops below a certain threshold it will automatically disable the watchdog timer and reduces current consumption to 8.5µA.
The R5114 and R5115 are available with three options:
- Externally adjustable minimum output current setting by using a resistor
- Internally fixed minimum output current setting
- No minimum output current setting
R5114 / R5115 Features:
Input Voltage Range (Abs. Max. Rating) 3.5 V to 42 V (50 V)
Operating Temperature Range -40°C to +125°C
Supply Current Typ. 8.5 μA (WDT disabled), Typ. 13.5 μA (at no load, WDT enabled)
Standby Current Typ. 0.2 μA
Output Voltage Range 3.3 V to 5 V (in steps of 0.1 V)
Output Voltage Accuracy ±1.6% (-40°C ≤Ta≤+125°C)
Output Current 250 mA
Detection Voltage Threshold Range 2.5 V to 4.8 V (in steps of 0.1 V)
Detection Voltage Accuracy ±0.6% (25°C), ±1.6% (-40°C ≤Ta≤+125°C)
Watchdog Timer Accuracy ±25% (-40°C ≤Ta≤+125°C)
Protections: Thermal Shutdown, Output Current Limiting, Short-circuit Current Limiting
Packages HSOP-8E and HSOP-18 (6.20 x 5.20 x 1.50 mm)