R1540 Voltage Tracker ICs

Ricoh Electronic Devices' R15140 voltage tracker IC is for use in off-board sensors and modules in automotive applications

Image of Ricoh Electronic Devices' R1540 Voltage Tracker ICRicoh Electronic Devices' expands its portfolio with a voltage tracker IC for use in automotive applications. The R1540 is primarily intended as a power supply for off-board sensors and modules. It provides an additional safety level to keep the main power supply and associated critical circuits operational at all times.

New automotive vehicles are equipped with an increasing number of electronic systems for various purposes. All these circuits need to be supplied from a primary voltage source to a lower secondary source. Power management is usually performed by an on-board power supply, but external sensors and modules must be wired throughout the vehicle and are exposed to harsh conditions. The main power supply and the ECU processor and other essential circuits must remain operational and able to perform their tasks in the event of a failure in the off-board devices. Therefore, it is a popular measure to use so-called voltage trackers, where a reference voltage is replicated with high tracking accuracy and the safety level of the electronic system is generally increased.

The R1540 has a wide input voltage range up from 3.5 V to 42 V, which makes it possible to use the voltage tracker in numerous cases. A regulator output voltage may vary due to electromagnetic noise interference (EMI), advanced technology is built-in to prevent such voltage variation. According to severe tests conducted in Ricoh's laboratories, it has been confirmed that the R1540 has superior immunity to EMI noise over a broad frequency band (150 kHz to1 GHz). Furthermore, it has a high ripple rejection ratio of 80 dB and a fast response to transients on input and load. Some sensors require a highly accurate supply voltage to perform sensitive measurements; therefore, the voltage tracker provides a tracking precision of ±15 mV. The combined CE/ADJ pin lead is used to provide the input voltage as a reference for the output, and it can be pulled low to control the device in standby mode.

The R1540 has a series of safety features that protect the voltage tracker and other parts of the application from possible damage and defects.

Protection Circuits
  • Overcurrent protection: limiting the output current in the event of overload
  • Short protection: embedded fold-back short current limit circuit detects a short circuit and decreases the output current to a safe level of 40 mA, after removing the short circuit the regulator automatically resumes normal operation
  • Thermal protection: incorporated and will turn off the output voltage when an excess temperature of 165°C is detected and will resume to normal operation again as soon a temperature of 135°C is reached
  • Protected pin lay-out: a special lay-out was arranged for the R1540S in HSOP-8E package preventing a malfunction when adjacent pins are shorted; all four terminals are isolated with unconnected adjacent pins
  • Input voltage range (maximum rating): 3.5 V to 42.0 V (50.0 V)
  • Supply current: typ. 60 µA
  • Standby current: typ. 0.1 µA
  • Tracking voltage range: 2.2 V to 14 V
  • Package R1540S: 5.2 mm x 6.2 mm x 1.5 mm (L x W X H) HSOP-8E
  • Tracking voltage accuracy: (-40°C = TA = 105°C, VCE/ADJ = 5 V) ±15 mV
  • Output current: 70 mA
  • Ripple rejection: typ. 80 dB (f = 100 Hz to 10 kHz)
  • Protections: thermal shutdown, output current limiting and short-circuit current limiting
  • Package R1540N: (2.9 mm x 2.8 mm x 1.1 mm (L x W x H) SOT-23-5
Published: 2019-09-11