Technical Note

3/20

BD9757MWV

www.rohm.com

2010.11 - Rev.A

© 2010 ROHM Co., Ltd. All rights reserved.

●Electrical characteristics (Unless specified, Ta=25℃, VCCOUT=5.0V, VBAT=3V, STB13 ~ 7=3V,UPIC8=2.5V)

Parameter

Symbol

Limits

Unit

Conditions

Min.

Typ.

Max.

【Internal regulator VREGA】

Output voltage

VREGA

2.4

2.5

2.6

V

Io=5mA

【Low-voltage input malfunction prevention circuit】

Detecting voltage 1

Vstd1

-

2.0

2.3

V

VREGA monitor

Hysteresis width 1

⊿Vstd1

50

100

200

mV

Detecting voltage 2

Vstd2

-

2.4

2.5

V

VCCOUT monitor

Hysteresis width 2

⊿Vstd2

100

200

300

mV

【Short-circuit protection circuit】

SCP detecting time

Tscp

20

25

30

msec

Timer start threshold voltage

Vtcinv

0.38

0. 48

0.58

V

INV terminal monitor

CH3 ~ 5

【Start circuit】

Oscillating frequency

Fstart

150

300

600

kHz

Operation initiation VBAT voltage

Vst1

1.5

-

-

V

Start-up CH soft start time

Tss1

1.8

3.0

5.3

msec

【Oscillating circuit】

Oscillating frequency CH1 ~ 5

fosc1

1.0

1.2

1.4

MHz

Oscillating frequency CH6 ~ 8

fosc2

0.5

0.6

0.7

MHz

Max duty 2,3,4,5(voltage step-down)

Dmax1d

-

-

100

%

Max duty 1(voltage boost)

Dmax1u

86

92

96

%

Max duty 6,7,8

Dmax2

86

92

96

%

【Error AMP】

Input bias current

IINV

-

0

50

nA

INV1 ~ 8, NON5=3.0V

INV threshold 1

VINV1

0.79

0.80

0.81

V

CH1 ~ 5

INV threshold 2

VINV2

0.99

1.00

1.01

V

CH7,8V

INV threshold 3

(max)

VINV3

370

400

430

mV

CH8I

【Base Bias Voltage Vref for inverted Channel】

CH6 output voltage

VOUT6

-6.09

-6.00

-5.91

V

NON6 12k

Ω, 72kΩ

Line regulation

DVLi

-

4.0

12.5

mV

VCCOUT=1.5 ~ 5.5V

Output circuit at the time of short-circuit

Ios

0.2

1.0

-

mA

Vref=0V

【Soft start】

CH2, 5 soft start time

Tss2, 5

3.4

4.4

5.4

msec

CH3, 4 soft start time

Tss3, 4

1.2

2.2

3.2

msec

CH6 soft start time

Tss6

3.4

4.4

5.4

msec

CH7, 8 soft start time

Tss7, 8

4.4

5.4

6.6

msec

※2

The protective circuit start working when circuit is operated by 100% duty.

So it is possible to use only for transition time shorter than charge time for SCP.

※3

Recommend resistor value over 20kΩ between VREF to NON6, because VREF current is under 100µA.

◎

This product is not designed for normal operation within a radioactive environment.