GPIO ICs Keyencoder IC No.11098EBT04 BU1852GUW, BU1852GXW Description Keyencoder IC BU1852 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 3A 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 VDDVDDIO Supply Voltage VDDIO -0.3 ~ +4.5 V 1 VI1 -0.3 ~ VDD +0.3 V XRST, XI, TW, PORENB 1 Input voltage VI2 -0.3 ~ VDDIO +0.3 V ADR XINT, SCL, SDA, VIT -0.3 ~ +4.5 V COL 11:0 , ROW 7:0 Storage temperature range Tstg -55 ~ +125 2 Package power PD 272 mW 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 2.72mW/ when the ambient temperature increases beyond 25. Operating conditions Ratings Parameter Symbol Unit Conditions Min. Typ. Max. Supply voltage range VDD 1.65 1.80 1.95 V (VDD) 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 2012.08 - Rev.B 1/25 2012 ROHM Co., Ltd. All rights reserved. Technical Note BU1852GUW, BU1852GXW Electrical characteristics 1. DC characteristics (VDD=1.8V, VDDIO=1.8V, Ta=25) Limits Parameter Symbol Unit Conditions Min. Typ. Max. 1 Input H Voltage1 V 0.8xVDD - 3.6 V IH1 2 Input H Voltage2 V 0.8xVDD - VDD+0.2 V IH2 Input H Voltage3 V 0.8xVDDIO - 3.6 V COL 11:0 IH3 Input H Voltage4 V 0.8xVDDIO - VDDIO+0.2 V ADR IH4 3 Input L Voltage1 V -0.2 - 0.2xVDD V IL1 Input L Voltage2 V -0.2 - 0.2xVDDIO V ADR, COL 11:0 IL2 4 V =3.60V IN Input H Current1 I -1.0 - 1.0 A IH1 Pull-down/up OFF 5 Input H Current2 I -1.0 - 1.0 A V =1.80V IH2 IN V =0V IN Input L Current I -1.0 - 1.0 A IL Pull-down/up OFF Output H Voltage1 V 0.75xVDD - - V I =-2mA, ROW 7:0 OH1 OH Output H Voltage2 V 0.75xVDDIO - - V I =-2mA, COL 11:0 OH2 OH 6 Output L Voltage1 V - - 0.25xVDD V I =2mA, OL1 OL Output L Voltage2 V - - 0.25xVDDIO V I =2mA, COL 11:0 OL2 OL 1 XINT,SCL,SDA,ROW 7:0 2 XRST,XI,TW,PORENB 3 XINT,SCL,SDA,ROW 7:0 ,XRST,XI,TW,PORENB 4 XINT,SCL,SDA,ROW 7:0 ,COL 11:0 5 XRST,XI,TW,PORENB,ADR 6 XINT,SDA,ROW 7:0 2. Circuit Current (VDD=1.8V, VDDIO=1.8V, Ta=25) Limits Parameter Symbol Unit Conditions Min. Typ. Max. Power Down Current I - - 1.0 A PD (VDD) XRST=VSS Power Down Current I - - 1.0 A PDIO (VDDIO) Standby Current1 I - - 3.0 A STBY1 (VDD) XRST=VDD, PORENB=VSS, Standby Current1 SCL=VDD, SDA=VDD I - - 1.0 A STBYIO1 (VDDIO) Standby Current2 I - - 1.0 A STBY2 XRST=VDD, (VDD) PORENB=VDD, Standby Current2 SCL=VDD, SDA=VDD I - - 1.0 A STBYIO2 (VDDIO) Operating Current Internal oscillator is used. I - 50 110 A OP (VDD) one key is pressed. www.rohm.com 2012.08 - Rev.B 2/25 2012 ROHM Co., Ltd. All rights reserved.