Ricoh launches a Voltage Tracker IC for off-board sensors and modules in Automotive applications

Jul 1, 2019

Campbell, CA, July 1, 2019 - Ricoh Electronic Devices Co., Ltd. in Japan has expanded its portfolio with a Voltage Tracker IC that is widely used in automotive applications. It is primarily intended as a power supply for off-board sensors and modules and 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. It must be ensured that the main power supply remains operational in the event of a failure in the off-board devices and that the ECU processor or other essential circuits continue to perform its task. 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 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 our 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 serves two purposes, it 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.

  • Over-current protection, limiting the output current in the event of overload.

  • Short protection, an 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 to normal operation.

  • Thermal protection is 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 were shorted. All four terminals are isolated with unconnected adjacent pins.

The R1540 is available in two packages; a regular SOT-23-5 and larger HSOP-8E package, samples and evaluation boards are available through our worldwide local distributor network as well as online distributors Mouser and Digi-Key.

Features R1540

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

Tracking Voltage Accuracy: (−40°C ≤ Ta ≤ 105°C, VCE/ADJ = 5 V) ± 15 mV

Output Current: 70 mA

Ripple Rejection: Typ. 80 dB (f = 100Hz to 10kHz)

Protections: Thermal Shutdown, Output Current Limiting and Short-circuit Current Limiting

Package R1540N: (L2.9 x W2.8 x H1.1 mm ) SOT-23-5

Package R1540S: (L5.2 x W6.2 x H1.5 mm ) HSOP-8E


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Ricoh is empowering digital workplaces using innovative technologies and services enabling individuals to work smarter. For more than 80 years, Ricoh has been driving innovation and is a leading provider of document management solutions, IT services, commercial and industrial printing, digital cameras, and industrial systems.

Headquartered in Tokyo, Ricoh Group operates in approximately 200 countries and regions. In the financial year ended March 2019, Ricoh Group had worldwide sales of 2,013 billion yen (approx. 18.1 billion USD).

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