FUJITSU MB3881

FUJITSU SEMICONDUCTOR
DATA SHEET
DS04-27224-1E
ASSP For Power Management Applications
8-ch DC/DC Converter IC with Synchronous
Rectifier for Voltage Step-up and Step-down
MB3881
■ DESCRIPTION
The MB3881 a step-up/step-down type of 8-channel, DC/DC converter IC. It uses pulse width modulation (PWM)
and synchronous rectification, designed for low voltage, high efficiency, and compactness. This IC is ideal for
down conversion and up/down conversion (employing a step-up/step-down Zeta system enabling free I/O setting).
The MB3881 can use channel 8 as its own power supply to provide a wide range of supply voltages, allowing
itself to operate at low voltage.
In addition, the MB3881 contains a triangular wave oscillator which can operate in synchronization with an external
device, allowing the switching timing to be controlled externally. This contributes to reduction in switching noise,
facilitating system configuration.
The MB3881 is designed to be compact using the LQFP-64P package whose body size is 7 × 7 mm.
The IC is the best for the power supply for advanced portable equipment such as a camera integrated VTR.
■ FEATURES
•
•
•
•
•
•
•
•
Supporting the step-up/step-down Zeta methods (CH1 to CH7)
Supporting synchronous rectification (CH1, CH2)
Low start-up voltage : 1.8 V (CH8)
Power-supply voltage range : 4 V to 13 V (CH1 to CH7)
Built-in high-precision reference voltage generator : 2.5 V ± 1%
Oscillation frequency range : 100 kHz to 800 kHz
Built-in triangular wave oscillator capable of external synchronization
Error amplifier output for soft start (CH1 to CH4, CH7)
■ PACKAGE
64-pin plastic LQFP
(FPT-64P-M16)
2
22
+IN5
(CH5,CH6)
Control block
27
28
29
30
31
32
VCC
CTL-2
CTL-3
CTL-4
CS
26
CTL-1
25
GND
CSCP
24
21
−IN5
23
20
FB5
VREF
19
−IN5(C)
18
OVP
17
DTC5
−IN6(C)
(CH7,CH8)
GND(O)-2
1
48
DTC1
RB8
2
47
FB1
DTC8
3
46
−IN1
FB8
4
45
DTC2
−IN8
5
44
FB2
+IN8
6
43
−IN2
−IN8(C)
7
42
DTC3
+IN8(C)
8
41
FB3
DTC7
9
40
−IN3
FB7
10
39
DTC4
−IN7
11
38
FB4
+IN7
12
37
−IN4
DTC6
13
36
VB
FB6
14
35
SYNC
−IN6
15
34
CT
+IN6
16
33
RT
(CH1 to CH4)
OUT8
VSS(O)-2
OUT7
OUT6
OUT5
VCC(O)-2
VCC(O)-1
OUT4
OUT3
GND(O)-1
OUT2-2
OUT2-1
VDD (O)
OUT1-2
OUT1-1
VSS(O)-1
64
63
62
61
60
59
58
57
56
55
54
53
52
51
50
49
MB3881
■ PIN ASSIGNMENT
Output block
MB3881
■ PIN DESCRIPTION
Pin No.
CH1
CH2
CH3
CH4
CH5
CH5, CH6
CH6
CH7
Symbol
I/O
Descriptions
47
FB1
O
Error amplifier output pin.
46
−IN1
I
Error amplifier inverted input pin.
48
DTC1
I
Dead time control pin.
50
OUT1-1
O
Main side output pin.
51
OUT1-2
O
Synchronous rectifier side output pin.
44
FB2
O
Error amplifier output pin.
43
−IN2
I
Error amplifier inverted input pin.
45
DTC2
I
Dead time control pin.
53
OUT2-1
O
Main side output pin.
54
OUT2-2
O
Synchronous rectifier side output pin.
41
FB3
O
Error amplifier output pin.
40
−IN3
I
Error amplifier inverted input pin.
42
DTC3
I
Dead time control pin.
56
OUT3
O
Output pin.
38
FB4
O
Error amplifier output pin.
37
−IN4
I
Error amplifier inverted input pin.
39
DTC4
I
Dead time control pin.
57
OUT4
O
Output pin.
20
FB5
O
Error amplifier output pin.
21
−IN5
I
Error amplifier inverted input pin.
22
+IN5
I
Error amplifier non-inverted input pin.
23
−IN5 (C)
I
Short detection comparator input pin.
19
DTC5
I
Dead time control pin.
60
OUT5
O
Output pin.
18
OVP
I
Output maximum voltage setting pin.
14
FB6
O
Error amplifier output pin.
15
−IN6
I
Error amplifier inverted input pin.
16
+IN6
I
Error amplifier non-inverted input pin.
17
−IN6 (C)
I
Short detection comparator input pin.
13
DTC6
I
Dead time control pin.
61
OUT6
O
Output pin.
10
FB7
O
Error amplifier output pin.
11
−IN7
I
Error amplifier inverted input pin.
12
+IN7
I
Error amplifier non-inverted input pin.
9
DTC7
I
Dead time control pin.
62
OUT7
O
Output pin.
(Continued)
3
MB3881
(Continued)
Pin No.
CH8
OSC
Symbol
I/O
4
FB8
O
Error amplifier output pin.
5
−IN8
I
Error amplifier inverted input pin.
6
+IN8
I
Error amplifier non-inverted input pin.
7
−IN8 (C)
I
Short detection comparator inverted input pin.
8
+IN8 (C)
I
Short detection comparator non-inverted input pin.
3
DTC8
I
Dead time control pin.
2
RB8

Output current setting pin.
64
OUT8
O
Output pin.
33
RT

Triangular wave frquency setting resistor connection pin.
34
CT

Triangular wave frquency setting capacitor connection pin
35
SYNC
I
External synchronous signal input pin.
28
CTL-1
I
Power supply, CH 1, 3, 4, 8 control circuit.
“H” level : Power supply operating mode
“L”level : Standby mode
I
CH 2 control circuit.
•CTL-1pin = “H” level
“H” level : CH2 operating mode
“L” level : CH2 OFF mode
I
CH5, 6 control circuit.
•CTL-1pin = “H” level
“H” level : CH5, CH6 operating mode
“L” level : CH5, CH6 OFF mode
CH7 control circuit.
•CTL-1pin = “H” level
“H” level : CH7 operating mode
“L” level : CH7 OFF mode
29
Control
Power
4
30
CTL-2
CTL-3
Descriptions
31
CTL-4
I
26
CSCP

Short protection circuit capacitor connection pin.
32
CS

CH1, 2, 3, 4, 7 soft start circuit capacitor connection pin.
27
VCC

Reference voltage and control circuit power supply pin.
58
VCC (O) -1

CH1, 2, 3, 4 output circuit power supply pin.
59
VCC (O) -2

CH5, 6, 7, 8 output circuit power supply pin.
49
VSS (O) -1

CH1, 2, 3, 4 output circuit power supply pin.
63
VSS (O) -2

CH5, 6, 7 output circuit power supply pin.
52
VDD (O)

CH1, 2 synchronous rectifier side output circuit power supply pin.
24
VREF
O
Refernce voltage output pin.
36
VB
O
Triangular wave oscillator regulator output pin.
25
GND

Ground pin.
55
GND (O) -1

CH1, 2, 3, 4 output circuit ground pin.
1
GND (O) -2

CH5, 6, 7, 8 output circuit ground pin.
MB3881
■ BLOCK DIAGRAM
• General view
PWM
Comp.1-1
+
+
−
FB1 47
Error
− Amp.1
+
+
−IN1 46
58 VCC(O)-1
CH1
Drive
1-1
50 OUT1-1
49 VSS(O)-1
PWM
VB1 Comp.1-2
+
1.25 V
SCP
Comp.1
−
52 VDD(O)
Drive
1-2
−
+
+
51 OUT1-2
1.0 V
DTC1 48
PWM
Comp.2-1
+
+
−
FB2 44
Error
− Amp.2
+
+
−IN2 43
CH2
Drive
2-1
53 OUT2-1
Drive
2-2
54 OUT2-2
PWM
VB2 Comp.2-2
+
1.25 V
SCP
Comp.2
−
+
+
−
1.0 V
DTC2 45
Error
− Amp.3
+
+
−IN3 40
A
CH3
PWM
Comp.3
+
+
−
FB3 41
Drive
3
56 OUT3
1.25 V
SCP
Comp.3
−
+
+
1.0 V
DTC3 42
Error
− Amp.4
+
+
−IN4 37
CH4
PWM
Comp.4
+
+
−
FB4 38
Drive
4
57 OUT4
1.25 V
SCP
Comp.4
−
+
+
1.0 V
DTC4 39
55 GND(O)-1
FB5 20
Error
− Amp.5
+
+
−IN5 21
59 VCC(O)-2
CH5
PWM
Comp.5
+
+
−
Drive
5
60 OUT5
63 VSS(O)-2
0.6 V SCP
Comp.5
−
−IN5(C) 23
+IN5 22
+
DTC5 19
Error
− Amp.6
+
+
−IN6 15
CH6
PWM
Comp.6
+
+
−
FB6 14
Drive
6
61 OUT6
B
0.6 V SCP
Comp.6
−
−IN6(C) 17
+IN6 16
+
OVP 18
DTC6 13
Error
− Amp.7
+
+
+
−IN7 11
+IN7 12
CH7
PWM
Comp.7
+
+
−
FB7 10
Drive
7
62 OUT7
1.25 V
SCP
Comp.7
−
+
+
+
20 kΩ
80 kΩ
1.0 V
DTC7 9
CH8
FB8 4
Error
Amp.8
−
−IN8 5
PWM
Comp.8
−
−
+
+
Drive
8
64 OUT8
+IN8 6
2 RB8
−IN8(C) 7
−
+IN8(C) 8
+
SCP
Comp.8
DTC8 3
1 GND(O)-2
C
CTL-2 29
CTL-3 30
CTL
1, 3, 4 CS CTL
Logic
CTL-4 31
CT1 1.73 V
1.0 V
CT2 1.73 V
1.0 V
CT
0.8 V
0.3 V
Buff
Buff
×0.8
CS 32
27 VCC
UVLO
VB 36
OSC
SCP
2V
35
33
34
26
SYNC RT
CT
CSCP
Power
Ref ON/OFF
CTL
2.5 V
24
VREF
25
GND
28 CTL-1 H : ON (Power/CH1, 3, 4, 8)
L : OFF (Standby mode)
(64 pin)
5
MB3881
• Enlarged view of A
PWM
Comp.1-1
+
+
−
FB1 47
−IN1 46
Error
− Amp.1
+
+
CH1
Drive
1-1
58 VCC(O)-1
50 OUT1-1
49 VSS(O)-1
VB1
1.25 V
SCP
Comp.1
−
PWM
Comp.1-2
+
−
+
+
52 VDD(O)
Drive
1-2
51 OUT1-2
1.0 V
DTC1 48
PWM
Comp.2-1
+
+
−
FB2 44
−IN2 43
Error
− Amp.2
+
+
1.25 V
SCP
Comp.2
−
+
+
VB2
CH2
Drive
2-1
53 OUT2-1
Drive
2-2
54 OUT2-2
PWM
Comp.2-2
+
−
1.0 V
DTC2 45
FB3 41
−IN3 40
Error
− Amp.3
+
+
PWM
Comp.3
+
+
−
CH3
Drive
3
56 OUT3
1.25 V
SCP
Comp.3
−
+
+
1.0 V
DTC3 42
FB4 38
−IN4 37
Error
− Amp.4
+
+
PWM
Comp.4
+
+
−
CH4
Drive
4
57 OUT4
1.25 V
SCP
Comp.4
−
+
+
1.0 V
DTC4 39
55 GND(O)-1
6
MB3881
• Enlarged view of B
FB5 20
−IN5 21
−IN5(C) 23
+IN5 22
Error
− Amp.5
+
+
PWM
Comp.5
+
+
−
CH5
Drive
5
59 VCC(O)-2
60 OUT5
63 VSS(O)-2
0.6 V SCP
Comp.5
−
+
DTC5 19
FB6 14
−IN6 15
−IN6(C) 17
+IN6 16
Error
− Amp.6
+
+
PWM
Comp.6
+
+
−
CH6
Drive
6
61 OUT6
0.6 V SCP
Comp.6
−
+
OVP 18
DTC6 13
FB7 10
−IN7 11
+IN7 12
20 kΩ
80 kΩ
Error
− Amp.7
+
+
+
PWM
Comp.7
+
+
−
CH7
Drive
7
62 OUT7
1.25 V
SCP
Comp.7
−
+
+
+
1.0 V
DTC7 9
7
MB3881
• Enlarged view of C
CH8
FB8 4
Error
Amp.8
−
−IN8 5
PWM
Comp.8
−
−
+
+
Drive
8
64 OUT8
+IN8 6
2 RB8
−IN8(C) 7
−
+IN8(C) 8
+
SCP
Comp.8
DTC8 3
1 GND(O)-2
CTL-2 29
CTL-3 30
CTL
1, 3, 4 CS CTL
Logic
CTL-4 31
CT1
1.73 V
1.0 V
CT2 1.73 V
1.0 V
CT
0.8 V
0.3 V
Buff
Buff
×0.8
CS 32
27 VCC
UVLO
VB 36
OSC
Ref
2V
35
8
SCP
33
34
26
SYNC RT
CT
CSCP
2.5 V
24
VREF
Power
ON/OFF
CTL
25
GND
28
H : ON (Power/CH1, 3, 4, 8)
L : OFF (Standby mode)
CTL-1 (64 pin)
MB3881
■ ABSOLUTE MAXIMUM RATINGS
Parameter
Symbol
Condition
VCC
VDD
Power supply voltage
Rating
Unit
Min.
Max.


17
V


17
V
Output current
IO
OUT pin

20
mA
Output peak current
IO
OUT pin, Duty ≤ 5%

200
mA
Power dissipation
PD
Ta ≤ +25 °C

800*
mW
Storage temperature
Tstg

−55
+125
°C
* : The packages are mounted on the epoxy board (10 cm × 10 cm).
WARNING: Semiconductor devices can be permanently damaged by application of stress (voltage, current,
temperature, etc.) in excess of absolute maximum ratings. Do not exceed these ratings.
■ RECOMMENDED OPERATING CONDITIONS
Parameter
Symbol
Condition
CH8
Power supply voltage
VCC
CH1 to CH7,
4 V ≤ VCC(O)−VSS(O) ≤ 9 V
Value
Unit
Min.
Typ.
Max.
1.8
9
13
V
4
9
13
V
VDD
CH1
4
5
9
V
Reference voltage output current
IOR
VREF pin
−1

0
mA
Reference voltage output current
IB
VB pin
−0.5

0
mA
+IN5, +IN6, −IN1 to −IN7,
−IN5 (C) , −IN6 (C) , OVP pin
0

VCC − 1.8
V
+IN8, −IN8, −IN8 (C) , +IN8 (C) pin
0

VCC − 0.9
V
+IN7 pin
0.1

VCC − 1.8
V
Input voltage
VIN
Control input voltage
VCTL
CTL pin
0

VCC
V
SYNC input voltage
VSYNC
SYNC pin
0

VCC
V
Output current
IO
OUT pin
1
2
15
mA
Output current setting resister
RB
RB8 pin
2.4
24
51
kΩ
Oscillator frequency
fOSC

100
500
800
kHz
Timing capacitor
CT

47
100
680
pF
Timing resistor
RT

6.8
11
51
kΩ
VB pin capacitor
CVB

0.22
0.39

µF
Soft-start capacitor
CS


0.1
1.0
µF
CSCP


0.1
1.0
µF
Short detection capacitor
Operating ambient temperature
Ta

−30
+25
+85
°C
WARNING: The recommended operating conditions are required in order to ensure the normal operation of the
semiconductor device. All of the device’s electrical characteristics are warranted when the device is
operated within these ranges.
Always use semiconductor devices within their recommended operating condition ranges. Operation
outside these ranges may adversely affect reliability and could result in device failure.
No warranty is made with respect to uses, operating conditions, or combinations not represented on
the data sheet. Users considering application outside the listed conditions are advised to contact their
FUJITSU representatives beforehand.
9
MB3881
CH1 to CH7
CH8
Triangular
wave oscillator
block (OSC)
Short circuit
detection block
(SCP)
Soft-start
block (CS)
Under voltage
lockout protection
circuit block(U.V.L.O)
Reference
voltage
block
■ ELECTRICAL CHARACTERISTICS
(Ta = +25 °C, VCC = 9 V, VSS = 4.4 V, VDD = 5 V)
Value
Conditions
Unit
Min. Typ. Max.
Parameter
Symbol
Pin No.
Reference voltage
VREF
24
∆VREF/
VREF
24
Ta = −30 °C to +85 °C
Input stability
Line
24
Load stability
Load
Short-circuit output
current

2.475
2.5
2.525
V

0.5*

%
VCC = 4 V to 13 V
−10

10
mV
24
VREF = 0 mA to −1 mA
−10

10
mV
Ios
24
VREF = 2 V
−20
−5
−1
mA
Threshold voltage
VTH
50
VCC =
2.6
2.8
3.0
V
Hysteresis width
VH
50

0.2

V
Reset voltage
VRST
50
VCC =
1.20
1.30
1.40
V
Threshold voltage
VTH
64
VCC =
1.25
1.45
1.65
V
Input standby voltage
VSTB
32


50
100
mV
Charge current
ICS
32

−1.4
−1.0
−0.6
µA
Threshold voltage
VTH
26

0.65
0.70
0.75
V
Input standby voltage
VSTB
26


50
100
mV
VI
26


50
100
mV
Input source current
ICSCP
26

−1.4
−1.0
−0.6
µA
Oscillator frequency
fOSC
50, 53, 56, 57, 60, CT = 100 pF, RT = 11 kΩ
450
61, 62, 64, 51, 54 VB = 2 V
500
550
kHz
Frequency stability
for voltage
∆f/fdv
50, 53, 56, 57, 60,
VCC = 4 V to 13 V
61, 62, 64, 51, 54

1
10
%
Frequency stability
for temperature
∆f/fdt
50, 53, 56, 57, 60,
Ta = −30 °C to +85 °C
61, 62, 64, 51, 54

1*

%
Output voltage
temperature stability
Input latch voltage
Output voltage
SYNC input condition
Input current
*: Standard design value.

VB
36

VIH
50
Input “H” level
VIL
50
ISYNC
35
1.980 2.000 2.020
V
2.0


V
Input “L” level
0

0.8
V
SYNC = 5 V

50
100
µA
(Continued)
10
MB3881
(Continued)
(Ta = +25 °C, VCC = 9 V, VSS = 4.4 V, VDD = 5 V)
Symbol
Pin No.
Threshold voltage
VTH
47, 44, 41,
38, 10
FB = 1.35 V
VT temperature stability
∆VT/
VT
47, 44, 41,
38, 10
IB
46, 43, 40,
37, 11
Parameter
Input bias current
Error amplifier block
(CH1 to CH4, CH7)
12
Value
Unit
Min.
Typ.
Max.
1.23
1.25
1.27
V
Ta = −30 °C to +85 °C

0.5*

%
−IN = 0 V
(CH1 to CH4, CH7)
−320
−60

nA
+IN = 1 V (CH7)
8
10
15
µA
Voltage gain
AV
47, 44, 41,
38, 10
DC
60
100

dB
Frequency bandwidth
BW
47, 44, 41,
38, 10
AV = 0 dB

1.2*

MHz
VOH
47, 44, 41,
38, 10

2.2
2.4

V
VOL
47, 44, 41,
38, 10


50
200
mV
ISOURCE
47, 44, 41,
38, 10
FB = 1.35 V

−2.0
−1.0
mA
Output sink current
ISINK
47, 44, 41,
38, 10
FB = 1.35 V
70
140

µA
Input offset voltage
VIO
20, 21, 14, 15 FB = 1.35 V


10
mV
20, 21, 14, 15 Ta = −30 °C to +85 °C

0.5*

%
Output voltage
Output source current
VT temperature stability
Error amplifier bolck
(CH5, CH6)
Conditions
Input bias current
∆VT/
VT
IB
22, 16
FB = 1.35 V
−260
−40

nA
21, 15
−IN = 0 V
−120
−30

nA
FB = 1.35 V
−120
−30

nA
0

VCC − 1.8
V
18
Common mode input
voltage range
VCM
20, 14
Voltage gain
AV
20, 14
DC
60
100

dB
Frequency bandwidth
BW
20, 14
AV = 0 dB

1.2*

MHz
VOH
20, 14

2.2
2.4

V
VOL
20, 14


50
200
mV
ISOURCE
20, 14
FB = 1.35 V

−2.0
−1.0
mA
ISINK
20, 14
FB = 1.35 V
70
140

µA
Output voltage
Output source current
Output sink current

*: Standard design value.
(Continued)
11
MB3881
(Continued)
Parameter
Error amplifier bolck
(CH8)
Input offset voltage
Input bias current
SCP Comp. block
(CH1 to CH4, SCP)
SCP Comp. block
(CH5,CH6 SCP)
VIO
4, 5
IB
FB = 0.55 V
−15
0
15
mV
6
+IN = 0 V
−100
−20

nA
5
FB = 0.55 V
−50
−10

nA
0

VCC − 0.9
V
VCM
4
Voltage gain
AV
4
DC
60
75

dB
Frequency bandwidth
BW
4
AV = 0 dB

1.2*

MHz
VOH
4

1.1
1.3

V
VOL
4


5
200
mV
ISOURCE
4
FB = 0.55 V

−2.0
−1.0
mA
ISINK
4
FB = 0.55 V
60
140

µA
0.97
1.00
1.03
V
+IN = 1 V (CH7)
0.77
0.80
0.83
V
−IN = 0 V
−320
−60

nA
0.55
0.60
0.65
V
−200
−40

nA
Output voltage
Output sink current
SCP Comp.
block (CH8 SCP)
Pin No.
Common mode input
voltage range
Output source current
PWM Comp. block
(CH1 to CH7)
Symbol
(Ta = +25 °C, VCC = 9 V, VSS = 4.4 V, VDD = 5 V)
Value
Conditions
Unit
Min.
Typ.
Max.

50, 53, 56, 57 CH1 to CH4
Threshold voltage
VTH
62
IB
46, 43, 40,
11, 37
VIO
60, 61
IB
23, 17
Common mode input
voltage range
VCM
60, 61

0

VCC − 1.8
V
Input offset voltage
VIO
64

−15
0
15
mV
IB
7
−50
−10

nA
VCM
64
0

VCC − 0.9
V
VT0
50
Duty cycle = 0%
0.9
1.0

V
VT100
50
Duty cycle = 100%

1.73
1.83
V
−1.0
−0.3

µA
Input bias current
Input offset voltage
Input bias current
Input bias current
Common mode input
voltage range
Threshold voltage
Input bias current
IDTC

−IN (C) = 0 V
FB = 0.55 V

48, 45, 42, 39, DTC = 0.4 V
19, 13, 9
(CH1 to CH7)
*: Standard design value.
(Continued)
12
MB3881
(Continued)
Output block
(CH1 to CH7)
(Drive-1)
PWM Comp.
block(CH8)
Parameter
Symbol
Pin No.
VT0
64
Duty cycle = 0%
0.2
0.3

V
VT100
64
Duty cycle = 100%

0.8
0.9
V
Threshold voltage
Output source current ISOURCE
50, 53, 56, 57, Duty ≤ 5%,
60, 61, 62
OUT = 4.4 V

−100

mA
Output sink current
ISINK
50, 53, 56, 57, Duty ≤ 5%,
60, 61, 62
OUT = 9 V

80

mA
ROH
50, 53, 56, 57,
OUT = −15 mA
60, 61, 62

22
35
Ω
ROL
50, 53, 56, 57,
OUT = 15 mA
60, 61, 62

17
26
Ω
Output block
(CH1, CH2)
(Drive-2)
Output ON resistor
Output source current ISOURCE
51, 54
Duty ≤ 5%,
OUT = 0 V

−110

mA
Output sink current
ISINK
51, 54
Duty ≤ 5%,
OUT = 5 V

100

mA
ROH
51, 54
OUT = −15 mA

20
32
Ω
ROL
51, 54
OUT = 15 mA

16
25
Ω
Output source current ISOURCE
64
RB = 24 kΩ,
OUT = 0.7 V
−2.6
−2.0
−1.4
mA
Output sink current
64
Duty ≤ 5%,
OUT = 0 V

40

mA
1.5

13
V
Output block
(CTL-1 to CTL-4)
(CTL)
Output block
(CH8) (Drive)
Output ON resistor
ISINK
VIH
28, 29, 30, 31 Active mode
VIL
28, 29, 30, 31 Standby mode
0

0.5
V
ICTL
28, 29, 30, 31 CTL = 5 V

100
200
µA
CTL input condition
Input current
Standby current
General
(Ta = +25 °C, VCC = 9 V, VSS = 4.4 V, VDD = 5 V)
Value
Conditions
Unit
Min. Typ. Max.
ICCS
27
CTL-1 = 0 V


10
µA
ICCS (O)
58, 59
CTL-1 = 0 V


10
µA
IDDS
52
CTL-1 = 0 V


10
µA
ICC
27, 58, 59
CTL-1 = CTL-2
= CTL-3 = CTL-4 = 5 V

7
11
mA
IDD
52
CTL-1 = CTL-2
= CTL-3 = CTL-4 = 5 V


10
µA
Power supply current
*: Standard design value.
13
MB3881
■ TYPICAL CHARACTERISTICS
10
5
Ta = +25 °C
CTL−1 = CTL−2 = CTL−3 = CTL−4 = 5 V
8
6
4
2
0
0
2
4
6
8
10
12
14
Reference voltage vs. power supply voltage
Reference voltage VREF (V)
Power supply current ICC (mA)
Power supply current vs. power supply voltage
16
Ta = +25 °C
CTL−1 = CTL−2 = CTL−3 = CTL−4 = 5 V
VREF = 0 mA
4
3
2
1
0
0
2
Power supply voltage VCC (V)
4
6
8
10
12
14
16
Power supply voltage VCC (V)
Reference voltage vs. ambient temperature
Reference voltage VREF (V)
2.56
VCC = 9 V
CTL−1 = CTL−2 = CTL−3 = CTL−4 = 5 V
2.54
2.52
2.5
2.48
2.46
2.44
−40
−20
0
20
40
60
80
100
Ambient temperature Ta (°C)
Control current vs. control voltage
500
5
Ta = +25 °C
VCC = 9 V
VREF = 0 mA
4
Control current (µA)
Reference voltage VREF (V)
Reference voltage vs. control voltage
3
2
1
0
Ta = +25 °C
VCC = 9 V
400
300
200
100
0
0
1
2
3
4
Control voltage VCTL-1 (V)
5
0
2
4
6
8
10
12
14
16
Control voltage VCTL-1 (V)
(Continued)
14
MB3881
(Continued)
Triangular wave upper and lower limit voltage
vs.triangular wave oscillator frequency
Ta = +25 °C
VCC = 9 V CT = 100 pF
0.9
0.8
Triangular wave upper and
lower limit voltage VCT (V)
Triangular wave upper and
lower limit voltage VCT (V)
1
Triangular wave upper and lower limit voltage
vs. ambient temperature
Upper
0.7
0.6
0.5
0.4
0.3
Lower
0.2
0.1
0
0
1
VCC = 9 V
RT = 11 kΩ CT = 100 pF
0.9
0.8
Upper
0.7
0.6
0.5
0.4
0.3
Lower
0.2
0.1
0
−40
100 200 300 400 500 600 700 800 900 1000
−20
Triangular wave oscillator
frequency fOSC (kHz)
Triangular wave oscillator frequency
fOSC (kHz)
60
80
100
Ta = +25 °C
VCC = 9 V
1000
RT = 6.8 kΩ
100
RT = 11 kΩ
RT = 51 kΩ
1
10
100
1000
10000
CT = 220 pF
CT = 470 pF
CT = 680 pF
10
1k
10 k
Timing capacitor CT (pF)
Power dissipation vs. ambient temperature
VCC = 9 V
CTL−1 = CTL−2 = CTL−3 = CTL−4 = 5 V
RT = 11 kΩ
CT = 100 pF
540
520
500
480
460
−20
0
20
40
60
Ambient temperature Ta ( °C)
100 k
Timing resistor RT (Ω)
80
100
Power dissipation PD (mW)
560
440
−40
CT = 47 pF
CT = 100 pF
100
Triangular wave oscillator frequency
vs. ambient temperature
Triangular wave oscillator frequency
fOSC (kHz)
40
10000
Ta = +25 °C
VCC = 9 V
1000
10
20
Triangular wave oscillator frequency
vs. timing resistor
Triangular wave oscillator frequency
vs. timing capacitor
10000
0
Ambient temperature Ta ( °C)
Triangular wave oscillator frequency fOSC (kHz)
1000
800
600
400
200
0
−40
−20
0
20
40
60
80
100
Ambient temperature Ta ( °C)
(Continued)
15
MB3881
(Continued)
Error amplifier gain and phase vs. frequency (CH1)
Gain AV (dB)
20
90
φ
0
0
AV
−90
−20
VCC = 9 V
180
Phase φ (deg)
Ta = +25 °C
40
240 kΩ
10 kΩ
IN
− + 2.4 kΩ
10 µF
−
+
+
46
10 kΩ
1.4 V
47
OUT
1.26 V
−180
−40
1k
10 k
100 k
1M
10 M
Frequency f (Hz)
Error amplifier gain and phase vs. frequency (CH5)
Gain AV (dB)
20
90
φ
0
0
VCC = 9 V
180
AV
Phase φ (deg)
Ta = +25 °C
40
−20
−90
−40
−180
1k
10 k
100 k
1M
2.5 V
240 kΩ
10 kΩ
IN − +
10 kΩ
2.4 kΩ
10 µF
10 kΩ
−
+
+
21
22
18
1.4 V
20
OUT
10 kΩ
10 M
Frequency f (Hz)
Error amplifier gain and phase vs. frequency (CH8)
Gain AV (dB)
20
φ
90
0
0
AV
−20
−90
−40
−180
1k
10 k
100 k
1M
Frequency f (Hz)
16
VCC = 9 V
180
10 M
1V
Phase φ (deg)
Ta = +25 °C
40
240 kΩ
10 kΩ
IN
10 kΩ
− + 2.4 kΩ
5
−
6
+
10 µF
10 kΩ
4
10 kΩ
OUT
MB3881
■ FUNCTIONS
1. DC-DC Converter Functions
(1) Reference voltage generator
The reference voltage generator generates a temperature-compensated reference voltage (typically =: 2.5 V)
from the voltage supplied from the power supply terminal (pin 27). The voltage is used as the reference voltage
for the IC’s internal circuitry.
The reference voltage can supply a load current of up to 1 mA to an external device through the VREF terminal
(pin 24).
(2) Triangular-wave oscillator circuit
The triangular wave oscillator incorporates a timing capacitor and a timing resistor connected respectively to
the CT terminal (pin 34) and RT terminal (pin 33) to generate triangular oscillation waveform CT (amplitude of
0.3 to 0.8 V), CT1 (amplitude 1.0 to 1.73 V in phase with CT), or CT2 (amplitude 1.0 to 1.73 V in inverse phase
with CT).
CT1 and CT2 are input to the PWM comparator in the IC.
(3) Error amplifier (Error Amp.)
The error amplifier detects the DC/DC converter output voltage and outputs PWM control signals. It supports
a wide range of in-phase input voltages from 0 V to “VCC - 1.8 V” (channels 1 to 7), allowing easy setting from
the external power supply.
In addition, an arbitrary loop gain can be set by connecting a feedback resistor and capacitor from the output
pin to inverted input pin of the error amplifier, enabling stable phase compensation to the system.
(4) PWM comparator (PWM Comp.)
The PWM comparator is a voltage-to-pulse width converter for controlling the output duty depending on the input
voltage.
Channels 1, 2 main sides, channel 3 to 8
: The comparator keeps the output transistor on while the
error amplifier output voltage and DTC voltage remain higher than
the triangular wave voltage.
Channels 1, 2 synchronous rectification sides:The comparator keeps the output transistor on while the error
amplifier output voltage remain lower than the triangular wave
voltage.
(5) Output circuits
The output circuits on the main side and on the synchronous rectification side are both in the totem pole
configuration, capable of driving an external PNP transistor (channels 1,2 main sides, channels 3 to 7), NPN
transistor (channel 8), and N-channel MOSFET (channels 1,2 synchronous rectification sides).
17
MB3881
2. Channel Control Function
Channels are turned on and off depending on the voltage levels at the CTL-1 terminal (pin 28), CTL-2 terminal
(pin 29), CTL-3 terminal (pin 30),and CTL-4 terminal (pin 31).
Voltage level at CTL pin
Channel On/Off Setting Conditions
Channel on/off state
CTL-1
CTL-2
CTL-3
CTL-4
L
×
×
×
L
L
H
H
L
H
H
Power
CH8
CH1, 3, 4
CH2
OFF
H
OFF
L
L
H
L
H
CH7
OFF (Standby state)
L
H
CH5, 6
ON
ON
OFF
ON
ON
OFF
ON
OFF
ON
OFF
ON
OFF
ON
× : Undefined
3. Protective Functions
(1) Timer-latch short-circuit protection circuit
The short-circuit detection comparator in each channel detects the output voltage level and, if any channel output
voltage falls below the short-circuit detection voltage, the timer circuits is actuated to start charging the external
capacitor CSCP connected to the CSCP terminal (pin 26).
When the capacitor voltage reaches about 0.70 V, the circuit is turned off the output transistor and sets the dead
time to 100%.
To reset the actuated protection circuit, turn the power supply on back. (See “SETTING TIME CONSTANT FOR
TIMER-LATCH SHORT-CIRCUIT PROTECTION CIRCUIT”.)
(2) Undervoltage lockout protection circuit
The transient state or a momentary decrease in supply voltage, which occurs when the power supply is turned
on, may cause the IC to malfunction, resulting in breakdown or degradation of the system. To prevent such
malfunctions, the undervoltage lockout protection circuit detects a decrease in internal reference voltage with
respect to the power supply voltage, turns off the output transistor, and sets the dead time to 100% while holding
the CSCP terminal (pin 26) at the “L” level.
The circuit restores the output transistor to normal when the supply voltage reaches the threshold voltage of the
undervoltage lockout protection circuit.
18
MB3881
4. Soft Start Operation
(1) Description
• When the CTL-1 to CTL-4 pins are driven high (“H” level)
The channel-8 output voltage is soft-started by the capacitor (C+IN8) connected to the +IN8 terminal (pin 6).
The capacitor (Cs) connected to the CS terminal (pin 32) starts being charged and the output voltages of channels
1 to 4 and channel 8 are soft-started by the error amplifier in proportion to the CS pin voltage.
Input
CTL-1 ( pin 28 )
CTL-2 ( pin 29 )
CTL-3 ( pin 30 )
CTL-4 ( pin 31 )
Output
2V
VB ( pin 36)
FB8 ( pin 4)
0.3 V
CH8 output voltage
VO8
2.5 V
VREF ( pin 24)
1.25 V
CS ( pin 32)
CH1 to CH4, CH7
output voltage
VO1 to VO4, VO7
CH5, CH6 output
voltage VO5, VO6
t
(1)
(2)
(3)
(4)
(1) to (4) : CH1 to CH4, CH7 soft start interval
(2) to (3) : CH8 soft start interval
19
MB3881
• When the CTL-2 (CTL-4) terminal is driven low (“L” level) after channels 1, 3, 4, and 8 have been soft-started
The capacitor (Cs) connected to the CS terminal (pin 32) starts being charged. The channel-2 (channel-7) output
voltage is soft-started by the error amplifier in proportion to the CS pin voltage.
Input
CTL-1 ( pin 28)
CTL-2 ( pin 29)
(CTL-4 ( pin 31) )
CTL-3 ( pin 30)
Output
2V
VB ( pin 36)
FB8 ( pin 4)
0.3 V
CH8 output voltage
VO8
2.5 V
VREF ( pin 24)
1.25 V
1.25 V
CS ( pin 32)
CH1, CH3, CH4
output voltage
VO1, VO3, VO4
CH2 (CH7) output voltage
VO2 (VO7)
CH5, CH6 output voltage
VO5, VO6
t
(1)
(2)
(3)
(5)
(1) to (4)
(2) to (3)
(5) to (6)
(5)’ to (6)’
20
(4)
(5)
(6)
: Channel-1, 3, 4 soft start interval
: Channel-8 soft start interval
: Channel-2 (channel-7) soft start interval
: Channel-2 (channel-7) soft start interval (waveform) as CTL-2 (CTL-4) goes
“H” from “L” during channel-1, 3, 4 soft start interval
(6)
MB3881
(2) Setting Soft Start
• Channel-8 soft start
Channel 8 can be soft-started by connecting a capacitor between the DTC8 terminal (pin 3) and GND. The soft
start time depends on the input voltage and load current.
• Channel 1 to 4 and channel 7 soft start
Soft start time
ts[s] =: 1.25 × Cs[µF]
Note : The short-circuit detection function remains working even during soft start operation of channels 1 to 4 and 7.
• Channel-5, 6 soft start
Channel 5 can be soft-started by connecting a capacitor between the +IN5 terminal (pin 22) and GND.
Channel 6, like channel 5, can be soft-started by connecting a capacitor between the +IN6 terminal (pin 16) and
GND.
■ SETTING THE OSCILLATION FREQUENCY
The oscillation frequency can be set by connecting the timing capacitor (CT) to the CT terminal (pin 34) and the
timing resistor (RT) to the RT terminal (pin 33).
Oscillation frequency
fOSC (kHz) =:
550000
CT (pF) × RT (kΩ)
21
MB3881
■ SETTING THE OUTPUT VOLTAGE
• CH1 to CH4
VO
FB1
47
R1
−
+
+
46
−IN1
R2
VO =
1.25 V
R2
(R1 + R2)
VO =
bV
R2
(R1 + R2)
Error
Amp.1
1.25 V
−
+
+
SCP
Comp.1
1.0 V
• CH5, CH6
VO
(aV > bV)
R1
−
+
+
21
−IN5
R2
Error
Amp.5
aV
0.6 V
−
23
−IN5(C)
+
22
+IN5
OVP
22
bV
18
SCP
Comp.5
MB3881
• CH7
VO
• +IN7 ≥ 1.25 V
FB7
VO =
11
R1
−
+
+
+
10
−IN7
R2
1.25 V
R2
(R1 + R2)
Error
Amp.7
• +IN7< 1.25 V
VO =
+IN7
R2
(R1 + R2)
1.25 V
12
+IN7
20 kΩ
−
+
+
+
80 kΩ
SCP
Comp.7
1.0 V
• CH8
VO
FB8
VO =
4
R1
−IN8
5
−
2Rb (R1 + R2)
(Ra + Rb) R2
Error
Amp.8
+
R2
Ra
+IN8
6
Rb
7
−
8
+IN8(C)
+
SCP
Comp.8
−IN8(C)
VB = 2 V
23
MB3881
■ SAMPLE POWER SUPPLY USING CHANNEL 8 AS SELF-POWER SUPPLY
Using channel 8 as the self-power supply, the MB3881 can support a wide range of supply voltages and operate
at low input voltage (Vin ≥ 1.8 V).
The following example shows sample power supply using a transformer.
VSS (O)
Vin
H
H
FB8
4
−IN8
5
−
VO8-1
(15 V)
<CCD>
VO8-2
(7 V)
<LCD>
VO8-3
(−7 V)
<CCD>
VO8-4
(−15 V)
<LCD>
Error
Amp.8
+
64
+IN8
6
OUT8
2
RB8
VCC
VCC (O)
The following settings are used in “APPLICATION EXAMPLE”.
• VSS(O) is set to the number of turnings that produces Vin - 1.8 V.
• VCC and VCC(O) are set to the number of turnings that produces Vin + 2.2 V.
Note that, because channels 1 to 4 operate at VCC ≥ 4 V, they must be set to the number of turnings that
produces Vin + 2.2 V or more so that they operate at Vin ≥ 1.8 V.
24
MB3881
■ SETTING THE OUTPUT CURRENT
The output circuit (drive 8) is structured as illustrated below (in the output circuit diagram). As found in “Output
Current Waveform” below, the source current value of the output current waveform has a constant current setting.
Note that the source current is set by the following equation:
Output source current : (VB / RB) × 80 =: 48 / RB[A] (VB =: 0.6 V)
VCC (O)−2
59
80 I
Source current
External NPN transistor
Output source
current
× 33
64
OUT8
Output sink
current
I
Sink current
70 kΩ
× 33
2
RB8
0.6 V
RB
VB =: 0.6 V
1 GND (O)−2
In the output circuit diagram
Output source current (Peak)
Output current
Output source
current
0
Output sink current (Peak)
t
Output current waveform
25
MB3881
■ SETTING TIME CONSTANT FOR TIMER-LATCH SHORT-CIRCUIT PROTECTION CIRCUIT
The short detection comparator (SCP comparator) in each channel monitors the output voltage.
While the switching regulator load conditions are stable on all channels, the LOG_SCP output remains at "H"
level, transistor Q1 is turned on, and the CSCP terminal (pin 26) is held at “L” level.
If the load condition on a channel changes rapidly due to a short of the load, causing the output voltage to drop,
the output of the short detection comparator on that channel goes to “H” level. This causes transistor Q1 to be
turned off and the external short protection capacitor CSCP connected to the CSCP terminal to be charged at 1.0
µA.
When the capacitor CSCP is charged to the threshold voltage (VTH =: 0.70 V), the latch is set and the external
FET is turned off (dead time is set to 100%). At this point, the latch input is closed and the CSCP terminal is
held at “L” level.
Short detection time (tPE)
tPE (s) =: 0.70 × CSCP (µF)
External PNP transistor
VO1
R1
−
+
+
46
−IN1
R2
SCP
Comp.1
Drive
1−1
50
OUT1−1
1.0 V
Drive
1−2
−IN8(C)
7
−
8
+
+IN8(C)
SCP
Comp.8
LOG_SCP
Drive
8
1 µA
CSCP
bias
Q1
R
S
Timer-latch short
protection circuit
UVLO
Ref
Timer-latch short circuit protection circuit
26
64
OUT8
bias
26
CSCP
51
OUT1−2
Power
ON/OFF CTL
28
CTL−1
MB3881
■ SETTING FOR EXTERNAL SYNCHRONOUS OSCILLATION
For external synchronous operation, connect the timing capacitor (CT) to the CT terminal (pin 34) and the timing
resistor (RT) to the RT terminal (pin 33).
In this case, select the CT and RT so that the oscillation frequency is 5% to 10% lower than the frequency of the
external synchronous signal excluding the setting error of the oscillation frequency.
The duty cycle (T1/T) of the external synchronous signal must be set within a range from 10% to 90%.
Triangular wave oscillator (OSC) equivalent circuit
VB
Latch1
−
S
Q
+
0.8 V
I
R
CT
34
−
CT
+
0.3 V
“H” level: ON
1.5 I
Ι: Proportional to VRT/RT
SYNC
35
100 kΩ
1.4 V
+
Latch2
−
S
Q
R
External synchronization circuit
Free-run oscillation
External synchronous oscillation
0.8 V
0.8 V
VCT
VCT
0.3 V
0.3 V
5.0 V
5.0 V
VSYNC
VSYNC
0V
0V
t
T1
t
T
Note: If the external synchronous pulse is not input, the device is started with free-run oscillation.
For free-run oscillation, set the SYNC terminal (pin 35) to “Lo” or “HiZ” level.
The external synchronization circuit starts operation after a VREF rise.
The CT pin oscillation frequency at startup is 500 kHz when the voltage at the VB terminal (pin 36) is 2 V
with CT = 100 pF and RT = 11 kΩ.
If the triangular wave has superimposed noise during external synchronous oscillation, insert a CR filter.
27
MB3881
■ TREATMENT WITHOUT USING CSCP
When you do not use the timer-latch short protection circuit, connect the CSCP terminal (pin 26) to GND with
the shortest distance
CSCP
26
Treatment when not using CSCP
■ TREATMENT FOR KILLING THE SOFT START FEATURE
To disable the channel 1 to 4, 7 soft start function, leave the CS terminal (pin 32) open.
To disable the channel 8 soft start function, remove the capacitor from the +IN8 terminal (pin 16).
“Open”
CS
32
VB
6
When no soft start time is set
28
+IN8
MB3881
■ SETTING THE DEAD TIME
When the device is set for step-up inverted output based on the step-up or step-up/down Zeta method or flyback
method, the FB pin voltage may reach and exceed the rectangular wave voltage due to load fluctuation. If this
is the case, the output transistor is fixed to a full-ON state (ON duty = 100%). To prevent this, set the maximum
duty of the output transistor. To set it, set the voltage at the DTC1 terminal (pin 48) by applying a resistive voltage
divider to the VREF voltage as shown below.
When the voltage at the DTC1 terminal (pin 48) is higher than the triangular wave voltage (CT1), the output
transistor is turned on. The maximum duty calculation formula assuming that triangular wave amplitude =: 0.73
V and triangular wave minimum voltage =: 1.0 V is given below. (Same to other channels.)
DUTY (ON) max=:
Vdt − 1.0 V
Rb
× 100[%], Vdt =
0.73 V
Ra + Rb
× VREF
When the DTC1 terminal (pin 48) is not used, connect it directly to the VREF terminal (pin 24) as shown below.
(Same to other channels.)
VREF
24
DTC1
48
Ra
Rb
Vdt
When using DTC to set dead time (Same to other channels.) ( CH1)
VREF
24
DTC1
48
When no soft start time is set ( Same to other channels.) ( CH 1)
29
MB3881
■ APPLICATION EXAMPLE
• General view
Vo1
(2.0 V)
A
FB1
47
C21
0.1 µF
R9
1 kΩ
A
R17
12 kΩ
50
49
46
−IN1
R18
20 kΩ
CH1
L1
Q1
VCC(O)-1
58
33 µH
R1
OUT1-1 240 Ω
C13
2200 pF
VSS(O)-1
C33
C1
1 µF
Q9 D1 2.2 µF
52
VDD(O)
51
DTC1
OUT1-2
48
FB2
44
C22
0.1 µF
R10
1 kΩ
B
R19
20 kΩ
53
DTC2
L2
15 µH
C34
C2
1 µF
Q10 D2 2.2 µF
A
CH2
54
R33
24 kΩ
15 µH
C14
3900 pF
43
−IN2
R20
16 kΩ
Vo2
(2.8 V)
B
C8 2.2 µF L3
Q2
R2
75 Ω
OUT2-1
OUT2-2
Vo3
(5.0 V)
45
R34
47 kΩ
C
C9 2.2 µF L5
Q3
FB3
41
C23
0.1 µF
R11
R21
39 kΩ 1 kΩ
C
56
R46
24 kΩ
DTC3
L4
6.8 µH
C15
3900 pF
40
−IN3
R22
13 kΩ
15 µH
R3
75 Ω
OUT3
C35
C3
1 µF
D3 2.2 µF
CH3
42
R47
47 kΩ
Vo4
(5.0 V)
D
C10 2.2 µF L7
Q4
FB4
38
C24
0.1 µF
R12
R23
39 kΩ 1 kΩ
D
57
R35
24 kΩ
DTC4
(3.6 V)
GND(O)-1
20
C25
0.1 µF
R13
1 kΩ
60
21
−IN5
−IN5(C)
+IN5
DTC5
63
CH5
R26
20 kΩ
Motor
control
signal
D4 2.2 µF
55
FB5
E
C4
1 µF
39
59
R25
5.1
kΩ
C36
CH4
R36
47 kΩ
Vin
L6
6.8 µH
C16
3900 pF
37
−IN4
R24
13 kΩ
15 µH
R4
75 Ω
OUT4
Vo5
(DRUM)
E
L8
Q5
VCC(O)-2
R5
3 kΩ
OUT5
33 µH
C17
470 pF
C37
C5
1 µF
D5 2.2 µF
VSS(O)-2
23
B
22
19
Vo6
(CAP)
F
L9
Q6
FB6
14
C26
0.1 µF
R14
R27
15 1 kΩ
15
kΩ
−IN6
R28
20 kΩ
F
−IN6(C)
61
33 µH
R6
1 kΩ
OUT6
C18
680 pF
C38
C6
1 µF
D6 2.2 µF
CH6
17
Motor
control
signal
16
+IN6
R43 24 kΩ OVP
18
Over
R44
voltage
47 kΩ
threshold
setting
voltage
DTC6
13
Vo7
(B.L)
G
C11 2.2 µF L11
Q7
FB7
G
R29
75
kΩ
10
C27
0.1 µF
R15
1 kΩ
62
15 µH
R7
100 Ω
OUT7
C39
L10
15 µH
C7
D7 2.2 µF
1 µF
C19
2200 pF
11
−IN7
R30
15 kΩ
+IN7
CH7
12
Back light luminousity switching
signal
R37 24 kΩ DTC7
9
R38
47 kΩ
H
FB8
4
C28
R31 0.1 µF
130 kΩ 1R16
kΩ
5
−IN8
R32
10 kΩ
VCC(0)
(5.8 V)
R39
30 kΩ +IN8
R40
10 kΩ
H
VSS(0)
(1.8 V)
6
C46
1 µF
64
CH8
T1
D10 C42
1 µF
Vo8-1
(15 V)
<CCD>
Vo8-2
(7 V)
C43 <LCD>
1 µF Vo8-3
(−7 V)
<CCD>
C44
1 µF
Vo8-4
(−15 V)
D13
C45 <LCD>
1 µF
D11
D12
2
RB8
R8
12 kΩ
8
+IN8(C)
R41
C41
1 µF D9
Q8
C20
100 pF
7
−IN8(C)
R48 68 kΩ
R49
10 kΩ
OUT8
C40
1 µF D8
DTC8
GND(O)-2
3
1
36 kΩ R42
20 kΩ
27
C
VCC
CTL-2 29
28 CTL-1
CTL-3 30
CTL-4 31
CS
H : ON (Power/CH1, 3, 4, 8)
L : OFF (Standby mode)
32
C30
0.1 µF
VB 36
C32
0.1 µF
35
Synchronous signal
3V∼5V
0V
30
SYNC
RT
R45
12 kΩ
33
34
CT C31
100 pF
26
CSCP
24
VREF
C29
0.1 µF
25
GND
(64 pin)
MB3881
• Enlarged view of A
Vo1
(2.0 V)
A
VCC(O)-1
58
FB1
A
R17
12 kΩ
R18
20 kΩ
47
C21
0.1 µF
R9
1 kΩ
50
49
46
−IN1
CH1
33 µH
R1
OUT1-1 240 Ω
C13
2200 pF
VSS(O)-1
C33
C1
1 µF
Q9 D1 2.2 µF
52
VDD(O)
51
DTC1
L1
Q1
OUT1-2
48
B
C8 2.2 µF L3
Q2
FB2
B
R19
20 kΩ
R20
16 kΩ
44
C22
0.1 µF
R10
1 kΩ
53
43
−IN2
DTC2
L2
15 µH
C34
C2
1 µF
Q10 D2 2.2 µF
CH2
54
R33
24 kΩ
15 µH
R2
75 Ω
OUT2-1
C14
3900 pF
OUT2-2
Vo3
(5.0 V)
45
R34
47 kΩ
C
C9 2.2 µF L5
Q3
FB3
C
R21
39 kΩ
R22
13 kΩ
R46
24 kΩ
41
C23
0.1 µF
R11
1 kΩ
56
40
−IN3
DTC3
15 µH
R3
75 Ω
OUT3
C15
3900 pF
L4
6.8 µH
C35
C3
1 µF
D3 2.2 µF
CH3
42
R47
47 kΩ
Q4
FB4
D
R23
39 kΩ
R24
13 kΩ
R35
24 kΩ
38
C24
0.1 µF
R12
1 kΩ
57
37
−IN4
DTC4
R36
47 kΩ
Vo2
(2.8 V)
15 µH
R4
75 Ω
OUT4
C16
3900 pF
Vo4
(5.0 V)
D
C10 2.2 µF L7
L6
6.8 µH
C36
C4
1 µF
D4 2.2 µF
CH4
39
GND(O)-1
55
31
MB3881
• Enlarged view of B
Vo5
(DRUM)
E
59
FB5
E
Vin
(3.6 V)
R25
5.1
kΩ
20
C25
0.1 µF
R13
1 kΩ
60
21
−IN5
R26
20 kΩ
−IN5(C)
Motor control
signal
+IN5
DTC5
63
L8
Q5
VCC(O)-2
R5
3 kΩ
OUT5
C17
470 pF
33 µH
C37
C5
1 µF
D5 2.2 µF
VSS(O)-2
CH5
23
22
19
Vo6
(CAP)
F
L9
Q6
FB6
F
R27
15
kΩ
14
C26
0.1 µF
R14
1 kΩ
61
R6
1 kΩ
OUT6
C18
680 pF
15
−IN6
33 µH
C38
C6
1 µF
D6 2.2 µF
R28
20 kΩ
−IN6(C)
CH6
17
Motor control
signal
16
+IN6
R43 24 kΩ OVP
18
R44
Overvoltage
47
kΩ
threshold
setting
voltage
DTC6
13
Vo7
(B.L)
G
C11 2.2 µF L11
Q7
FB7
G
R29
75 kΩ
10
C27
0.1 µF
R15
1 kΩ
62
R30
15 kΩ
CH7
+IN7
12
Back light
luminousity
switching signal
R37 24 kΩ DTC7
R38
47 kΩ
32
9
C39
C19
2200 pF
11
−IN7
15 µH
R7
100 Ω
OUT7
1 µF
L10
15 µH
C7
D7 2.2 µF
MB3881
• Enlarged view of C
H
FB8
4
C28
0.1
µF
R31
R16
130 kΩ 1 kΩ
5
−IN8
R32
10 kΩ
R39
30 kΩ
VSS(0)
(1.8 V)
VCC(0)
(5.8 V)
+IN8
R40
10 kΩ
H
6
CH8
C46
1 µF
64
C20
100 pF
T1
D10 C42
1 µF
D11
D12
C43
1 µF
C44
1 µF
D13
C45
1 µF
Vo8-1
(15 V)
<CCD>
Vo8-2
(7 V)
<LCD>
Vo8-3
(−7 V)
<CCD>
Vo8-4
(−15 V)
<LCD>
2
RB8
R8
12 kΩ
8
R49 +IN8(C)
10 kΩ
DTC8
GND(O)-2
3
1
36 kΩ R42
20 kΩ
27
VCC
CTL-2 29
28 CTL-1
CTL-3 30
CTL-4 31
CS
C41
1 µF D9
Q8
7
−IN8(C)
R48 68 kΩ
R41
OUT8
C40
1 µF D8
H : ON (Power/CH1, 3, 4, 8)
L : OFF ( Standby mode )
32
(64 pin)
C30
0.1 µF
VB 36
C32
0.1 µF
35
Synchronous signal SYNC
3V∼5V
0V
RT
R45
12 kΩ
33
34
CT
26
C31
100 pF
CSCP
24
VREF
C29
0.1 µF
25
GND
33
MB3881
■ PARTS LIST
COMPONENT
ITEM
SPECIFICATION
VENDOR
PARTS No.
Q1 to Q7
Q8
Q9, Q10
PNP Tr
NPN Tr
FET
VCEO = −12 V
VCEO = 15 V
VDSS = 30 V
SANYO
SANYO
Fairchild
CPH3106
CPH3206
NDS355AN
D1 to D9
D10 to D13
Diode
Diode
VF = 0.42 V (max.) , IR = 1 mA
VF = 0.77 V, IR = 10 µA (max.)
ORIGIN
ORIGIN
F1J2H
F02J9
L1
L2, L3
L4
L5
L6
L7
L8, L9
L10, L11
Coil
Coil
Coil
Coil
Coil
Coil
Coil
Coil
TDK
TDK
TDK
TDK
TDK
TDK
TDK
TDK
SLF6028T-330MR69
SLF6028T-150M1R0
SLF6028T-6R8M1R5
SLF6028T-150M1R0
SLF6028T-6R8M1R5
SLF6028T-150M1R0
SLF6028T-330MR69
SLF6028T-150M1R0
T1
Transformer
SUMIDA
CLQ72B
C1 to C11
C13
C14 to C16
C17
C18
C19
C20
C21 to C30
C31
C32
C33 to C46
Ceramics Condensor
Ceramics Condensor
Ceramics Condensor
Ceramics Condensor
Ceramics Condensor
Ceramics Condensor
Ceramics Condensor
Ceramics Condensor
Ceramics Condensor
Ceramics Condensor
Ceramics Condensor
2.2 µF
2200 pF
3900 pF
470 pF
680 pF
2200 pF
100 pF
0.1 µF
100 pF
0.1 µF
1 µF
16 V
50 V
50 V
50 V
50 V
50 V
50 V
16 V
50 V
16 V
25 V
R1
R2 to R4
R5
R6
R7
R8
R9 to R16
R17
R18, R19
R20
R21
R22
R23
R24
R25
R26
R27
R28
R29
R30
R31
R32
Resistor
Resistor
Resistor
Resistor
Resistor
Resistor
Resistor
Resistor
Resistor
Resistor
Resistor
Resistor
Resistor
Resistor
Resistor
Resistor
Resistor
Resistor
Resistor
Resistor
Resistor
Resistor
240 Ω
75 Ω
3 kΩ
1 kΩ
100 Ω
12 kΩ
1 kΩ
12 kΩ
20 kΩ
16 kΩ
39 kΩ
13 kΩ
39 kΩ
13 kΩ
5.1 kΩ
20 kΩ
15 kΩ
20 kΩ
75 kΩ
15 kΩ
130 kΩ
10 kΩ
1/16 W
1/16 W
1/16 W
1/16 W
1/16 W
1/16 W
1/16 W
1/16 W
1/16 W
1/16 W
1/16 W
1/16 W
1/16 W
1/16 W
1/16 W
1/16 W
1/16 W
1/16 W
1/16 W
1/16 W
1/16 W
1/16 W
33 µH
15 µH
6.8 µH
15 µH
6.8 µH
15 µH
33 µH
15 µH
0.69 A, 148 mΩ
1 A, 74.5 mΩ
1.5 A, 35.4 mΩ
1A, 74.5 mΩ
1.5 A, 35.4 mΩ
1 A, 74.5 mΩ
0.69 A, 148 mΩ
1 A, 74.5 mΩ
(Continued)
34
MB3881
(Continued)
COMPONENT
ITEM
R33
R34
R35
R36
R37
R38
R39
R40
R41
R42
R43
R44
R45
R46
R47
R48
R49
Resistor
Resistor
Resistor
Resistor
Resistor
Resistor
Resistor
Resistor
Resistor
Resistor
Resistor
Resistor
Resistor
Resistor
Resistor
Resistor
Resistor
SPECIFICATION
24 kΩ
47 kΩ
24 kΩ
47 kΩ
24 kΩ
47 kΩ
30 kΩ
10 kΩ
36 kΩ
20 kΩ
24 kΩ
47 kΩ
12 kΩ
24 kΩ
47 kΩ
68 kΩ
10 kΩ
VENDOR
PARTS No.
1/16 W
1/16 W
1/16 W
1/16 W
1/16 W
1/16 W
1/16 W
1/16 W
1/16 W
1/16 W
1/16 W
1/16 W
1/16 W
1/16 W
1/16 W
1/16 W
1/16 W
Note : SANYO : SANYO Electric Co., Ltd.
Fairchild : Fairchild Semiconductor Corporation
ORIGIN : Origin Electric Co., Ltd.
TDK : TDK Corporation
SUMIDA : Sumida Electric Co., Ltd.
35
MB3881
■ REFERENCE DATA
Conversion efficiency vs. load current
(CH1 : Down conversion method with synchronous rectification)
95
Iin
Conversion efficiency η (%)
94
93
To OUT1-1
92
L2
33 µH
Vin
R1
240 Ω
IL
C1
C37
91
1 µF
C15
2200 pF
90
VO1
(2.0 V)
A
Q1
Q9 D1 2.2 µF
To OUT1-2
η=
89
88
Ta = +25 °C
2 V output
VCC (O) = Vin + 2.2 V
VSS (O) = Vin − 1.8 V
87
86
85
0
Vin = 2.5 V
Vin = 3 V
Vin = 3.6 V
Vin = 4.2 V
Vin = 6 V
VO1 × IL
Vin × Iin
× 100 (%)
50 100 150 200 250 300 350 400 450 500
Load current IL (mA)
Conversion efficiency vs. load current
(CH2 : Zeta method with synchronous rectification)
90
Iin
Conversion efficiency η (%)
88
Q2 C10
15 µH
Vin
86
84
To OUT2-1
82
R2
75 Ω
L3
C38
C16
3900 pF
VO2
(2.8 V)
B
2.2 µF L4
1 µF
IL
15 µH
C2
Q10 D2 2.2 µF
80
To OUT2-2
78
76
Ta = +25 °C
2.8 V output
VCC (O) = Vin + 2.2 V
VSS (O) = Vin − 1.8 V
74
72
70
0
Vin = 2.5 V
Vin = 3 V
Vin = 3.6 V
Vin = 4.2 V
Vin = 6 V
η=
VO2 × IL
Vin × Iin
× 100 (%)
50 100 150 200 250 300 350 400 450 500
Load current IL (mA)
(Continued)
36
MB3881
(Continued)
Conversion efficiency vs. load current
(CH3 : Zeta method )
To VDD (O)
90
Conversion efficiency η (%)
88
Iin
86
Q3
C11
2.2 µF
To OUT3
R3
75 Ω
L5
C39 6.8 µH
82
C17
3900 pF
80
1 µF
Ta = +25 °C
5 V ouputt
VCC (O) = Vin + 2.2 V
VSS (O) = Vin − 1.8 V
74
72
70
0
Vin = 2.5 V
Vin = 3 V
Vin = 3.6 V
Vin = 4.2 V
Vin = 6 V
IL
C3
D3 2.2 µF
78
76
L6
15 µH
Vin
84
VO3
(5.0 V)
C
η=
VO3 × IL
Vin × Iin
× 100 (%)
50 100 150 200 250 300 350 400 450 500
Load current IL (mA)
37
MB3881
■ USAGE PRECAUTION
1. Never use setting exceeding maximum rated conditions.
Exceeding maximum rated conditions may cause permanent damage to the LSI.
Also, it is recommended that recommended operating conditions be observed in normal use.
Exceeding recommended operating conditions may adversely affect LSI reliability.
2. Use this device within recommended operating conditions.
Recommended operating conditions are values within which normal LSI operation is warranted.
Standard electrical characteristics are warranted within the range of recommended operating conditions and
within the listed conditions for each parameter.
3. Printed circuit board ground lines should be set up with consideration for common
impedance.
4. Take appropriate static electricity measures.
•
•
•
•
Containers for semiconductor materials should have anti-static protection or be made of conductive material.
After mounting, printed circuit boards should be stored and shipped in conductive bags or containers.
Work platforms, tools, and instruments should be properly grounded.
Working personnel should be grounded with resistance of 250 kΩ to 1 MΩ between body and ground.
5. Do not apply negative voltages.
The use of negative voltages below –0.3 V may create parasitic transistors on LSI lines, which can cause
abnormal operation.
■ ORDERING INFORMATION
Part number
MB3881PFF
38
Package
64-pin plastic LQFP
(FPT-64P-M16)
Remarks
MB3881
■ PACKAGE DIMENSION
64-pin plastic LQFP
(FPT-64P-M16)
9.00±0.20(.354±.008)SQ
1.70(.067)MAX
7.00±0.20(.276±.008)SQ
1.40±0.10
(.055±.004)
0.10±0.10
(.004±.004)
48
33
49
32
Details of "A" part
0.10(.004)
(1.00(.039))
INDEX
64
17
1
16
0.40(.016)
C
0.18±0.03
(.007±.001)
0.50±0.25
(.020±.010)
"A"
3.5°±3.5°
+0.10
0.15 –0.05
.006
+.004
–.002
1999 FUJITSU LIMITED F64027SC-2-1
Dimensions in: mm (inches)
39
MB3881
FUJITSU LIMITED
For further information please contact:
Japan
FUJITSU LIMITED
Corporate Global Business Support Division
Electronic Devices
KAWASAKI PLANT, 4-1-1, Kamikodanaka,
Nakahara-ku, Kawasaki-shi,
Kanagawa 211-8588, Japan
Tel: +81-44-754-3763
Fax: +81-44-754-3329
http://www.fujitsu.co.jp/
North and South America
FUJITSU MICROELECTRONICS, INC.
3545 North First Street,
San Jose, CA 95134-1804, USA
Tel: +1-408-922-9000
Fax: +1-408-922-9179
Customer Response Center
Mon. - Fri.: 7 am - 5 pm (PST)
Tel: +1-800-866-8608
Fax: +1-408-922-9179
http://www.fujitsumicro.com/
Europe
FUJITSU MICROELECTRONICS EUROPE GmbH
Am Siebenstein 6-10,
D-63303 Dreieich-Buchschlag,
Germany
Tel: +49-6103-690-0
Fax: +49-6103-690-122
http://www.fujitsu-fme.com/
Asia Pacific
FUJITSU MICROELECTRONICS ASIA PTE LTD
#05-08, 151 Lorong Chuan,
New Tech Park,
Singapore 556741
Tel: +65-281-0770
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F0004
 FUJITSU LIMITED Printed in Japan
All Rights Reserved.
The contents of this document are subject to change without
notice.
Customers are advised to consult with FUJITSU sales
representatives before ordering.
The information and circuit diagrams in this document are
presented as examples of semiconductor device applications,
and are not intended to be incorporated in devices for actual use.
Also, FUJITSU is unable to assume responsibility for
infringement of any patent rights or other rights of third parties
arising from the use of this information or circuit diagrams.
The contents of this document may not be reproduced or copied
without the permission of FUJITSU LIMITED.
FUJITSU semiconductor devices are intended for use in
standard applications (computers, office automation and other
office equipments, industrial, communications, and
measurement equipments, personal or household devices, etc.).
CAUTION:
Customers considering the use of our products in special
applications where failure or abnormal operation may directly
affect human lives or cause physical injury or property damage,
or where extremely high levels of reliability are demanded
(such as aerospace systems, atomic energy controls, sea floor
repeaters, vehicle operating controls, medical devices for life
support, etc.) are requested to consult with FUJITSU sales
representatives before such use. The company will not be
responsible for damages arising from such use without prior
approval.
Any semiconductor devices have inherently a certain rate of
failure. You must protect against injury, damage or loss from
such failures by incorporating safety design measures into your
facility and equipment such as redundancy, fire protection, and
prevention of over-current levels and other abnormal operating
conditions.
If any products described in this document represent goods or
technologies subject to certain restrictions on export under the
Foreign Exchange and Foreign Trade Control Law of Japan, the
prior authorization by Japanese government should be required
for export of those products from Japan.