BU97981KV-E2 Datasheet, PDF (36/50 Pages) Rohm – Multi-function LCD Segment Drivers

BU97981xxx Series MAX 196 segments (SEG49xCOM4)
Datasheet
Cautions of Power-On/ Power-Off condition
POR circuit
This LSI has “P.O.R” (Power-On Reset) circuit and Software Reset function.
Please keep the following recommended Power-On conditions in order to power up properly.
1. Please set power up conditions to meet the recommended tR, tF, tOFF, and Vbot spec below in order to ensure P.O.R
operation.
(The detection voltage of POR varies because of environment etc. To operate POR surely, Please satisfy Vbot lower
than 0.5V condition.)
VDD
VDET
tR
tOFF
Vbot
Recommendation condition of tR, tF, tOFF, Vbot
tR
tOFF
Vbot
less than 10ms Over 1ms less than 0.5V
VDET
TYP 1.2V
* VDET : POR detect level
Fig 18: Power ON/OFF wave
form
Figure 25. Power ON/OFF Wave
2. If it is difficult to meet above conditions, execute the following sequence after Power-On.
(1) CSB=”L”→”H” condition
(2) After CSB”H”→“L”, execute SWRST command.
In addition, in order to the SWRST command certainly, please wait 1ms after a VDD level reaches to 90% and
CSB=”L”→”H”.
Before SWRST command input device will be in unstable state, since SWRST command does not operate perfect
substitution of a POR function.
VDD
CSB
Min 1ms
Min 50ns
SWRST
Command
Figure 26. SWRST Command Sequence
www.rohm.com
© 2012 ROHM Co., Ltd. All rights reserved.
TSZ22111ï½¥15ï½¥001
36/46
TSZ02201-0A2A0D300110-1-2
10.Apr.2015 Rev.006