<MFT>

Preliminary

RT8H042C*This is tentative specification.

OUTLINE DRAWING

RT8H042C is composed by NPN transistors,
PNP transistors and resistors. This product has the resetfunction, and controls the backup function of the memoryof SRAM and the microcomputer (internal organs RAM)2.8±0.1
0.65±0.2 1.50±0.1 0.65±0.2

1.9±0.1

0.95±0.05

1.1±0.1

0.81

when the down of power and the power supply areabnormal. At the same time, RAM is switched from themain power supply to the backup power supply, the signal

2.80±0.2―――The reset signal（RES） is output to the microcomputer

Unit：mm①⑥②⑤③④0.33±0.05

DESCRIPTION―――

is switched to the backup circuit.

0～0.1

FEATURES

1.2±0.01（C S ）that becomes a stand-by state is output, and RAM●Miniaturization of a set.
●Detecting voltage（Power supply watch voltage）
Standard：1.23V―――●Chip selection signal output（C S ）

6―――

54

●Reset output（RES）

Pin layout―――

APPLICATION042

・ 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

１23①C S
②CT
③R
④VIN
⑤GND―――⑥RES

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

110428

<MFT>

Preliminary

RT8H042C*This is tentative specification.

ABSOLUTE MAXIMUM RATINGS (Ta＝25℃)
SymbolParameter

VIN
PdKθTjTstg

Operating supply voltage range

Internal power dissipation
Thermal derating
Junction temperature
Storage temperatureTopr

Operating temperature

Test conditions

Ratings

Unit(keep dry)

12200
1.6
150
－40～150V
mW
mW/℃℃℃(keep dry)

－20～75℃

Ta≧25℃

ELECTRICAL CHARACTERISTIC (Ta=25℃,VCC=3V unless otherwise noted.)
SymbolParameter

VIN

Operating supply
voltage range

Test conditions

Min

Designed value
Typ
Max

Unit

２-

10V

-

700

1050

uA

1.18

1.23

1.28

V

50

104

200

mV

0.65

1.32

2

V

--

0.3

V--

VIN

V--

0.5

V--

VIN

V--

0.5

V

9.0

18.0

27.0

ms-

-

0.5

uA

―――IINCircuit current

R E S -VIN：10kΩｐｕｌｌｕｐ――
CS ：10ｋΩ,3Vpullup，R：0V
―――

VRTH

R threshold voltage

R：H⇒L R E S -VIN：10kΩｐｕｌｌｕｐ――
CS ：10ｋΩ,3Vpullup,CT：OPEN⊿VRTHHysteresis

R：H⇒L ,R E S -VIN：10kΩｐｕｌｌｕｐ――
CS ：10ｋΩ,3Vpullup

―――

―――

CTH

Output voltage（Terminal CT in level HI）

R:2V,R E S -VIN：10kΩｐｕｌｌｕｐ――
CS ：10ｋΩ,3Vpullup

CTL

Output voltage（Terminal CT in level Low）

R：1V, R E S -VIN：10kΩｐｕｌｌｕｐ――
CS ：10ｋΩ,3Vpullup

Output voltage

R：2V, R E S -VIN：10kΩｐｕｌｌｕｐ――
CS ：10ｋΩ,3Vpullup

RRESL
RRESH
CSH

CSL

―――

（RES in level Low）
Output voltage―――（RES in level HI）
Output voltage――（CS in level HI）
Output voltage―――――――――――R E S ：1mA（SINK)

R：1V,CＳ：10ｋΩ,3Vpullup―――

R：1V,R E S -VIN：10kΩｐｕｌｌｕｐ――
CS ：10ｋΩ,3Vpullup――
CS ：1mA（SINK)―――（CS in level Low）

R：2V,R E S -VIN：10kΩｐｕｌｌｕｐ

TPD

Delay time

R：L⇒H ,R E S -VIN：10kΩｐｕｌｌｕｐ――
CS ：10ｋΩ,3Vpullup,CT：0.047uF

CSLEAKCS leak current（VIN in level Low）

―――――

―――

R E S -VIN：10kΩｐｕｌｌｕｐ――
R：LOW（１V)， CS ：10ｋΩ,3Vpullup

Delay time＝3.83 x 105 x Ct

110428Preliminary<MFT>

RT8H042C*This is tentative specification.

APPLICATION CIRCUIT EXAMPLES

Protective Resistor
Recommended parts
ISA１２３５AC1

Battery：3V110428

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Aug.2016