FUJITSU MICROELECTRONICS
DATA SHEET
DS04-27220-5Ea
ASSP For Power Supply Applications
6-ch DC/DC Converter IC
With Synchronous Rectifier
MB3825A
■
DESCRIPTION
The MB3825A is a pulse width modulation (PWM) type 6-channel DC/DC converter IC with synchronous rectifi-
cation (2-channels) designed for low voltage, high efficiency operation in high precision and high frequency
applications, ideal for down conversion.
The MB3825A is an ideal device offering low power consumption, compact size and light weight for products such
as self-contained camcorders and digital still cameras.
This product is covered by US Patent Number 6,147,477.
■
FEATURES
•
•
•
•
•
•
•
Synchronous rectification (channels 1 and 4)
High efficiency drive with power-on output enhanced by built-in speed-up circuit
Wide range of operating power supply voltage : 2.5 V to 12 V
Built-in high-precision reference voltage generator : 1.5 V
±
1%
Wide operating oscillator frequency range, high frequency capability : 50 kHz to 800 kHz
Wide input voltage range (all channels) : 0 V to Vcc
−
0.9 V
Error amplifier output for soft-start (channels 1, 2, 4) (All channels may be set for same soft-start time regardless
of duty factor setting.)
■
PACKAGE
64-pin plastic LQFP
64-pin plastic LQFP
(FPT-64P-M03)
(FPT-64P-M20)
Copyright©2003-2008 FUJITSU MICROELECTRONICS LIMITED All rights reserved
2003.8
MB3825A
■
PIN ASSIGNMENT
GND (O) 4
,
5
,
6
VCC (O) 4
,
5
,
6
GND (O) 1
,
2
,
3
VCC (O) 2
OUT2-4
OUT1-4
OUT1-3
OUT1-5
OUT1-2
50
CB1-4
CB2-4
CB2-3
CB1-3
64
63
62
61
60
59
58
57
56
55
54
53
52
51
49
48
47
46
45
44
43
42
41
40
39
38
37
36
35
34
33
CB2-2
VB4
VB3
CB2-5
CB1-5
VB5
OUT1-6
CB2-6
CB1-6
VB6
OVP5
,
6
IN (C) 6
+IN
(E) 6
−IN
(E) 6
FB6
SCP
IN (C) 5
+IN
(E) 5
−IN
(E) 5
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
CB1-2
VB2
OUT1-1
CB2-1
CB1-1
OUT2-1
VCC (O) 1
,
3
VB1
IN (C) 1
−IN
(E) 1
FB1
IN (C) 2
−IN
(E) 2
FB2
IN (C) 3
−IN
(E) 3
−IN
(E) 4
FB4
RT
IN (C) 4
CSCP
GND1
GND2
VREF
FB5
CT
CS
VCC
CTL2
CTL1
DTC3
2
FB3
MB3825A
■
PIN DESCRIPTION
Pin No.
38
39
40
CH 1
46
43
44
45
41
35
36
37
CH 2
50
48
49
47
32
33
34
CH 3
56
54
55
52
31
20
19
18
CH 4
57
60
59
58
62
Symbol
FB1
−IN
(E) 1
IN (C) 1
OUT1-1
OUT2-1
CB1-1
CB2-1
VB1
FB2
−IN
(E) 2
IN (C) 2
OUT1-2
CB1-2
CB2-2
VB2
FB3
−IN
(E) 3
IN (C) 3
OUT1-3
CB1-3
CB2-3
VB3
DTC3
FB4
−IN
(E) 4
IN (C) 4
OUT1-4
OUT2-4
CB1-4
CB2-4
VB4
I/O
O
I
I
O
O
O
I
I
O
O
I
I
O
I
O
I
I
O
O
Descriptions
Channel 1 error amplifier output terminal.
Channel 1 error amplifier inverted input terminal.
Channel 1 short detection comparator input terminal.
Channel 1 main side output terminal.
Channel 1 synchronous rectifier side output terminal.
Channel 1 boot capacitor connection terminal.
Channel 1 output sink current setting terminal.
Channel 2 error amplifier output terminal.
Channel 2 error amplifier inverted input terminal.
Channel 2 short detection comparator input terminal.
Channel 2 output terminal.
Channel 2 boot capacitor connection terminal.
Channel 2 output sink current setting terminal.
Channel 3 error amplifier output terminal.
Channel 3 error amplifier inverted input terminal.
Channel 3 short detection comparator input terminal.
Channel 3 output terminal.
Channel 3 boot capacitor connection terminal.
Channel 3 output sink current setting terminal.
Channel 3 dead time control terminal.
Channel 4 error amplifier output terminal.
Channel 4 error amplifier inverted input terminal.
Channel 4 short detection comparator input terminal.
Channel 4 main side output terminal.
Channel 4 synchronous rectifier side output terminal.
Channel 4 boot capacitor connection terminal.
Channel 4 output sink current setting terminal.
(Continued)
3
MB3825A
Pin No.
17
16
15
14
CH 5
64
2
1
3
8
12
11
10
9
CH 6
4
6
5
7
8
Triangular-
Wave
Oscillator
Circuit
21
22
Symbol
FB5
−IN
(E) 5
+IN
(E) 5
IN (C) 5
OUT1-5
CB1-5
CB2-5
VB5
OVP5, 6
FB6
−IN
(E) 6
+IN
(E) 6
IN (C) 6
OUT1-6
CB1-6
CB2-6
VB6
OVP5, 6
RT
CT
I/O
O
I
I
I
O
I
O
I
I
I
O
I
Descriptions
Channel 5 error amplifier output terminal.
Channel 5 error amplifier inverted input terminal.
Channel 5 error amplifier non-inverted input terminal.
Channel 5 short detection comparator input terminal.
Channel 5 output terminal.
Channel 5 boot capacitor connection terminal.
Channel 5 output sink current setting terminal.
Channel 5, 6 output maximum voltage setting terminal.
Channel 6 error amplifier output terminal.
Channel 6 error amplifier inverted input terminal.
Channel 6 error amplifier non-inverted input terminal.
Channel 6 short detection comparator input terminal.
Channel 6 output terminal.
Channel 6 boot capacitor connection terminal.
Channel 6 output sink current setting terminal.
Channel 5, 6 output maximum voltage setting terminal.
Triangular wave frequency setting resistor connection terminal.
Triangular wave frequency setting capacitor connection terminal.
Power supply control circuit.
“H” level : Power supply operating mode
“L” level : Standby mode
Channel 3 control circuit.
When CTL1 terminal is “H” level
“H” level : Channel 3 in operating mode
“L” level : Channel 3 in OFF mode
Short detection comparator input terminal.
Short protection circuit capacitor connection terminal.
Soft-start circuit capacitor connection terminal.
(Continued)
30
CTL1
I
Control Circuit
29
CTL2
I
13
23
26
SCP
CSCP
CS
I
4
MB3825A
(Continued)
Pin No.
28
42
51
63
Power Supply
Circuit
27
24
25
53
61
Symbol
VCC
VCC (O) 1, 3
VCC (O) 2
VCC (O) 4, 5, 6
VREF
GND1
GND2
GND (O) 1, 2, 3
GND (O) 4, 5, 6
I/O
O
Descriptions
Reference voltage and control circuit power supply terminal.
Output circuit power supply terminal (Channel 1, 3) .
Output circuit power supply terminal (Channel 2) .
Output circuit power supply terminal (Channel 4, 5, 6) .
Reference voltage output terminal.
Ground terminal.
Ground terminal.
Output circuit ground terminal (Channel 1, 2, 3) .
Output circuit ground terminal (Channel 4, 5, 6) .
5
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