ROHM BU1852GUW Data Sheet
Summary
The Keyencoder IC BU1852GUW is a high-functionality semiconductor designed to monitor complex keyboard matrices, supporting up to 96 keys in a Qwerty format. It significantly reduces CPU load by encoding only the change status of pressed or released keys, rather than storing all key states. This device offers advanced features like N-key Rollover, ghost key rejection, and built-in Power on Reset. Ideal for electronic device manufacturers (such as audio/visual, office automation, or amusement equipment) who require robust, low-power input monitoring and flexible GPIO selectability while needing ultra-low standby current consumption.
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GPIO ICs
Keyencoder IC
BU1852GUW No.11098EAT04
●Description Keyencoder IC BU1852GUW can monitor up to 8x12 matrix (96 keys), which means to be adaptable to Qwerty keyboard. We adopt the architecture that the information of the only key which status is changed, like push or release, is encoded into the 8 bits data. This can greatly reduce the CPU load which tends to become heavier as the number of keys increase. (Previously, all key's status is stored in the registers.) When the number of keys is small, the extra ports can be used as GPIO. Furthermore, auto sleep function contributes to low power consumption, when no keys are pressed. It is also equipped with the various functions such as ghost key rejection, N-key Rollover, Built-in power on reset and oscillator.
●Features 1) Monitor up to 96 matrix keys. 2) Under 3µA Stand-by Current 3) Built-in Power on Reset. 4) Ghost key rejection. 5) Keyscan / GPIO selectable 6) 3 volt tolerant Input
●Absolute maximum ratings (Ta=25℃)
Parameter Symbol Ratings Unit Conditions
VDD -0.3 ~ +2.5 V VDD≦VDDIO
Supply Voltage
VDDIO -0.3 ~ +4.5 V
VI1 -0.3 ~ VDD +0.3※1 V XRST, XI, TW, PORENB
Input voltage VI2 -0.3 ~ VDDIO +0.3※1 V ADR
VIT -0.3 ~ +4.5 V XINT, SCL, SDA,
COL[11:0], ROW[7:0]
Storage temperature range Tstg -55 ~ +125 ℃
Package power PD 272※2 m W ※ This IC is not designed to be X-ray proof. ※1 It is prohibited to exceed the absolute maximum ratings even including +0.3 V. ※2 Package dissipation will be reduced each 2.72m W/℃ when the ambient temperature increases beyond 25℃.
●Operating conditions
Ratings
Parameter Symbol Unit Conditions
Min. Typ. Max.
Supply voltage range (VDD) VDD 1.65 1.80 1.95 V Supply voltage range
VDDIO 1.65 1.80 3.60 V
(VDDIO)
VI1 -0.2 - VDD+0.2 V XRST, XI, TW, PORENB
Input voltage range VI2 -0.2 - VDDIO+0.2 V ADR
XINT, SCL, SDA,
VIT -0.2 - 3.60 V
COL[11:0], ROW[7:0]
Operating temperature range Topr -30 25 +85 ℃
www.rohm.com 2011.01 - Rev.A 1/24 © 2011 ROHM Co., Ltd. All rights reserved.
Page Summary Contents For ROHM BU1852GUW Data Sheet
Manual Details
| Brand | ROHM |
|---|---|
| Pages | 25 |
| File Size | 483.39 KB |
| Published | July 07, 2026 |
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Frequently Asked Questions
What is the maximum number of keys this IC can monitor?
It monitors up to an 8x12 matrix, allowing for a maximum of 96 keys.
Instead of logging all key statuses, how does it save CPU overhead?
The architecture only encodes the status changes (push or release) of active keys into 8 bits of data.
What is the standby current when no keys are pressed?
Under the Keyencoder IC BU1852GUW, the stand-by current is specified as under 3µA.
Can I use secondary ports for general GPIO functions?
Yes, if the total number of connected keys is small, unused extra ports can be utilized as selectable GPIOs.