Preliminary
*This is tentative specification.
<MFT>
RT8H042C
DESCRIPTION
RT8H042C is composed by NPN transistors,
PNP transistors and resistors. This product has the reset
function, and controls the backup function of the memory
of SRAM and the microcomputer (internal organs RAM)
OUTLINE DRAWING
2.8±0.1
0.65±0.2 1.50±0.1 0.65±0.2
①
⑥
⑤
④
Unit：mm
0.95±0.05
②
③
when the down of power and the power supply are
abnormal. At the same time, RAM is switched from the
main power supply to the backup power supply, the signal
（C S ）that becomes a stand-by state is output, and RAM
―――
1.1±0.1
is switched to the backup circuit.
0.81
FEATURES
●Miniaturization of a set.
●Detecting voltage（Power supply watch voltage）
Standard：1.23V
●Chip selection signal output（C S ）
●Reset output（RES）
―――
―――
6
5
4
0½0.1
Pin layout
①C S
②CT
③R
④VIN
⑤GND
⑥RES
―――
―――
APPLICATION
・ Backup of memories of 3V faction microcomputer
systems such as electronic office equipment,
industrial equipment, and home electrical appliances
・ Control system of power supply where switch of
external source and battery like SRAM board with built-in
backup function is needed
042
１
2
3
BLOCK DIAGRAM
VIN
コンパレーター
Comparator
R
-
+
Reset circuit
リセット回路
CS
遅延回路
Delay circuit
RES
CT
GND
1.2±0.01
0.33±0.05
2.80±0.2
1.9±0.1
The reset signal（RES） is output to the microcomputer
―――
110428
ISAHAYA [ ISAHAYA ELECTRONICS CORPORATION ]
