Technical Note

5/17

BU1850MUV

www.rohm.com

2009.09 - Rev.A

© 2009 ROHM Co., Ltd. All rights reserved.

●Functional Description

1.

Power Modes

The device enters the state of Power Down when XRST=”Low” or enters the operation state when XRST=High after

powered.

Refer to “Electrical Specification” section 5 for a detailed startup sequence.

1-1

Power supply

A single supply to Core power supply (VDD) and IO power supply (VDDIO) is prohibited.

Supply the power supply to the Core power supply and the IO power supply at the same time.

1-2

Power On Reset

A Power On Reset logic is implemented in this device. Therefore, it will operate correctly even if the XRST port is

not used. In this case, the XRST port must be connected to high(VDD).

1-3

State of Power Down

The device enters the state of Power Down by XRST=”Low”. An internal circuit is initialized and I

invalid is input. Power On Reset becomes inactive during this state.

1-4

State of operation

The device enters the operation state by setting XRST to "High". The I

the START condition. It becomes standby by the STOP condition. Power On Reset is active in this state.