ROHM BA6780FP-Y, BA6780 Datasheet

BA6780 / BA6780FP-Y

Optical disc ICs

2-channel driver for CD changers

BA6780 / BA6780FP-Y

The BA6780 and BA678 0FP-Y are 2-channel driver IC for CD chan gers that inculdes a reversible, variable s peed
electronic governor and a reversible driver. On sets that have dual-rail power supplies, the BA6780 and BA6780FP-Y can
be operated from just the negative supply to reduce influence on the positive power supply.
The input uses PW M control, and it is poss ible to directly input from a microprocessor running off the positi ve power
supply.

zApplications

Changers for CD players and MD players.

zFeatures

1) Output voltage can be freely set using the output voltage setting pin.

2) Internal mute function if the power supply voltage drops.

3) Thermal shutdown function. (Contains hysteresis)

4) PWM input.

5) Settable reference voltage output pin.

6) Wide operating supply voltage.

z

zAbsolute maximum ratings (T a = 25°C)

zz

Parameter Symbol Limits Unit

FIN, VRIN

V

Pd

CC

CC

IN

Power supply voltage V
Logic input voltage

Power dissipation

Maximum current consumption Imax 1.4 A
Operating temperature Topr −25∼+75 ˚C
Storage temperature Tstg −55∼+150 ˚C

∗1 When a DIP18 package is used.Reduced by 10.48mW for each increase inTa of 1˚C over 25˚C.
∗2 When mounted on a PCB board (70mm×70mm, t=1.6mm glass epoxy board).

Reduced by 11.6mW for each increase in Ta of 1˚C over 25˚C.

∗3 Should not exceed Pd or ASO values.

z

zRecommended operating conditions (T a = 25°C)

zz

Parameter Symbol Limits Unit
Power supply voltage V
Input voltage for Vin V

BA6780
BA6780FP-Y

18 V
22 V

∗1

1.31

∗2

1.45

∗3

7∼16 V

0∼V

CC

/ 2−1.0 V

W

Optical disc ICs

z

zBlock diagram and pin descriptions

zz

BA6780

BA6780 / BA6780FP-Y

VIN2 FIN2 RIN2 Cτ2 FBIN−V

18 17

V

IN

1/2

1 2

FWD/REV CONTROLLER

CC

V

THERMAL

SHUT DOWN

REVERSIBLE DRIVER

FWD/REV CONTROLLER

V

IN

16

GOVERNOR DRIVER

3

15 14 13 12 11 10

EE

V

V

EE

OUT

I

4 5 6 7 8 9

EE

V

EE

DETECTOR

40k40k

CC

V

Vref

10k

10k

10k

Vref

V

EE

20k

17.1k

Vconst

VregVrefIoutRIN1FIN1VIN1

Pin No. Pin name I/O Function

IN

1V

1 I Input pin for setting high output voltage for the reversible driver

2 FIN1 I Input pin for forward control signal for the reversible driver
3 RIN1 Input pin for reverse control signal for the reversible driver

I
4 Iout O Governor load current detector output (open collector )
5 Vref O Internal reference voltage pin
6 Vreg O 4.6V constant voltage output
7VCCI Power supply (+)
8 OUT1+ Reversible driver output (+)

O

9 OUT1− O Reversible driver output (−)

10 OUT2− O Governor output (−)
11 OUT2+ O Governor output (+)
12 FBIN+ I Governor load current detector amplifier input (+)
13 FBIN− Governor load current detector amplifier input (−)
14 V

EE

I

I Power supply (−) (connection within substrate)

15 Cτ 2 I For connection of capacitor for the governor PWM filter
16 RIN2 I Governor reverse control signal input
17 FIN2 I Governor forward control signal input

IN

18 V

1 Refer to operating notes.

∗

2 Input pin for setting high output voltage for the governor

I

FBIN+ OUT2+ OUT2−

3.2k

10k

10k

10k

Vref

V / I

V

EE

V

CC

CC

∗1

10k

Vref

DRIVE BUFFER

10k

Vref

DRIVE BUFFER

10k

10k

10k

Vref

OUT1−OUT1+V

Optical disc ICs

BA6780FP-Y

BA6780 / BA6780FP-Y

VIN2 FIN2 RIN2 Cτ2 FBIN−V

25

THERMAL

SHUT DOWN

1

1/2

V

IN

V

IN

22 21 20 19

2324

GOVERNOR DRIVER

FWD/REV CONTROLLER

CC

V

REVERSIBLE DRIVER

FWD/REV CONTROLLER

4 5 6 87

32

EE

V

V

EE

V

I

OUT

EE

V

EE

CC

V

40k40k

Vref

Pin No. Pin name I/O Function

1 N.C. −

IN

2V

1 I

3 N.C
4 FIN1 I
5 RIN1 I
6 Iout O
7 Vref O
8 Vreg
9V

CC

Input pin for setting high output voltage for the reversible driver

−

Input pin for forward control signal for the reversible driver
Input pin for reverse control signal for the reversible driver

Governor load current detector output (open collector )
Internal reference voltage pin

4.6V constant voltage output

O

I

Power supply (+)
10 N.C. −
11 OUT1+ O

Reversible driver output (+)
12 N.C. −
13 OUT1−
14 OUT2− O

Reversible driver output (−)

O

Governor output (−)
15 N.C. −
16 OUT2+ O
17 FB IN + I
18 FB IN −
19 V

EE

20 Cτ 2
21 R IN 2 I
22 F IN 2 I

Governor output (+)

Governor load current detector amplifier input (+)

Governor load current detector amplifier input (−)

I
I

Power supply (−) (connection within substrate)

I

For connection of capacitor for the governor PWM filter

Governor reverse control signal input

Governor forward control signal input
23 N.C. −
24 VIN2I
25 N.C.

1 Refer to operating notes.

∗

Input pin for setting high output voltage for the governor

−

V

VregVrefIoutRIN1FIN1VIN1

EE

EE

V

Vconst

FBIN+ OUT2+ OUT2−

16 15 1418

17

10k

10k

20k

17.1k

10k

Vref

3.2k

V

EE

V

CC

10

CC

∗1

10k

10k

Vref

EE

10k

10k

Vref

DRIVE BUFFER

10k

Vref

DRIVE BUFFER

11 12 139

10k

10k

10k

Vref

OUT1−OUT1+V

Optical disc ICs

z

zInput / output circuits ( ( ) :pins f or BA6780FP-Y )

zz

Pin function Equivalent circuit

pin 2, 3, 16, 17

( pin4, 5, 21, 22 )

85k

BA6780 / BA6780FP-Y

V

CC

Logic input

Voltage setting input

For connection of
capacitor for PWM
filter

pin1, 18

( pin2, 24 )

24k

V

EE

24k

V

V

EE

V

EE

10k

pin15

( pin20 )

EE

Load current detector

pin13

( pin18 )

V

EE

10k

10k

V

EE

10k

10k

V

EE

pin12

( pin17 )

Optical disc ICs

Pin function Equivalent circuit

V

CC

BA6780 / BA6780FP-Y

Output
(reversible driver)

Output
(governor)

10k

10k

pin8, 9

( pin11, 13 )

V

EE

V

CC

pin10, 11

( pin14, 16 )

V

EE

Load current detector
signal output
(governor)

pin4

( pin6 )

V

CC

1k

V

EE

V

EE