FUJITSU SEMICONDUCTOR
DATA SHEET
DS04-27212-3E
ASSP For Power Supply Applications
BIPOLAR
Switching Regulator Controller
(Low Voltage)
MB3800
s
DESCRIPTION
The MB3800 is a single-channel switching regulator control IC for low voltage applications incorporating a soft
start function and short circuit detection function. The device has a low minimum operating voltage of 1.8 V and
is ideal for the power supply of battery-operated electronic equipment.
s
FEATURES
•
•
•
•
•
•
•
•
•
Wide supply voltage operating range: 1.8 V to 15 V
Low current consumption: Typically 5.5 mA in operation, 1
µA
or less in stand-by
High speed operation is possible: Maximum 1 MHz
The error amplifier gain is set inside the IC, so peripheral components are minimized.
Incorporates a soft start circuit.
Incorporates a timer-latch type short circuit detection circuit (SCP).
Totem-pole type output with adjustable on/off current (for NPN transistors)
Incorporates a stand-by function.
Three types of packages (SOP-8 : 2 types, SSOP-8 : 1 type)
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PACKAGES
8-pin Plastic SOP
8-pin Plastic SOP
8-pin Plastic SSOP
(FPT-8P-M01)
(FPT-8P-M02)
(FPT-8P-M03)
MB3800
s
PIN ASSIGNMENT
(TOP VIEW)
–IN
1
8
FB
SCP
2
7
OSC
V
CC
3
6
GND
BR/CTL
4
5
OUT
(FPT-8P-M01)
(FPT-8P-M02)
(FPT-8P-M03)
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PIN DESCRIPTION
Pin No.
1
2
3
4
5
6
7
8
Symbol
–IN
SCP
V
CC
BR/CTL
OUT
GND
OSC
FB
I/O
I
—
—
I
O
—
—
O
Description
Error amplifier inverting input pin
Soft start and SCP setting capacitor connection pin
Power supply pin
Output current setting and control pin
Totem-pole type output pin
Ground pin
Capacitor and resistor connection pin for setting the oscillation frequency
Error amplifier output pin
2
MB3800
s
BLOCK DIAGRAM
V
CC
3
OSC
7
Reference
voltage supply
0.6 V–
0.1 V–
Sawtooth wave
oscillator
OUT
5
0.1 V
PWM
1.25 V
–IN
1
–
36 kΩ
–
Comp.
Error Amp.
0.5 V
500
Ω
FB
8
+
+
+
+
30 kΩ
Output drive
control circuit
0.3 V
DTC 0.6 V
Soft start SCP
6
GND
2
SCP
4
BR/CTL
(8 pin)
3
MB3800
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ABSOLUTE MAXIMUM RATINGS
(Ta = +25°C)
Parameter
Power supply voltage
Output source current
Output sink current
Allowable dissipation
Operating temperature
Storage temperature
Symbol
V
CC
I
O+
I
O–
FPT-8P-M01, Ta
≤
+25°C
P
D
T
op
T
stg
FPT-8P-M02, Ta
≤
+25°C
SSOP-8, Ta
≤
+25°C
—
—
Condition
Rating
Min
—
—
—
—
—
—
–30
–55
Max
16
–50
50
570*
430*
580*
+85
+125
Unit
V
mA
mA
mW
mW
mW
°C
°C
*: When mounted on a 10 cm square double-sided epoxy board.
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.
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RECOMMENDED OPERATING CONDITIONS
(Ta = +25°C)
Parameter
Power supply voltage
Error amplifier input voltage
BR/CTL pin input voltage
Output source current
Output sink current
SCP pin capacitance
Phase compensation capacitance
Output current setting resistance
Timing resistance
Timing capacitance
Oscillation frequency
Operating temperature
Symbol
V
CC
V
I
V
BR
I
O+
I
O–
C
PE
C
P
R
B
R
T
C
T
f
OSC
T
OP
Value
Min
1.8
–0.2
–0.2
–40
—
—
—
150
1.0
100
10
–30
Typ
—
—
—
—
—
0.1
0.1
390
3.0
270
500
+25
Max
15
1.0
V
CC
—
40
—
—
5000
10.0
10000
1000
+85
Unit
V
V
V
mA
mA
µF
µF
Ω
kΩ
pF
kHz
°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.
4
MB3800
s
ELECTRICAL CHARACTERISTICS
(V
CC
= +2 V, Ta = +25°C)
Parameter
Circuit to prevent
malfunction at low
input voltage
(U.V.L.O.)
Soft start
Short circuit
detection (S.C.P
.)
Reset voltage
Threshold voltage
Charging current
Voltage at soft start
completion
Charging current
Threshold voltage
Oscillation frequency
Sawtooth wave
oscillator (OSC)
Frequency input
stability
Frequency variation
with temperature
Input threshold
voltage
V
T
input stability
V
T
variation with
temperature
Input bias current
Error amplifier
Voltage gain
Frequency bandwidth
Maximum output
voltage range
Output source current
Output sink current
Idle period
adjustment section
Maximum duty cycle
Symbol
V
R
—
V
TH
I
CS
V
tS
I
CPC
V
tPC
f
OCS
f
dV
f
dT
V
T
V
TdV
V
TdT
I
B
A
V
BW
V
OM+
V
OM–
I
OM+
I
OM–
t
DUTY
V
FB
= 0.45 V
R
T
= 3.0 kΩ, C
T
= 270 pF
V
FB
= 0.8 V
A
V
= 0 dB
—
V
SCP
= 0 V
—
R
T
= 3.0 kΩ, C
T
= 270 pF
V
CC
= 2 V to 15 V
Ta = –30°C to +85°C
V
FB
= 450 mV
V
CC
= 2 V to 15 V
Ta = –30°C to +85°C
V
IN
= 0 V
—
V
SCP
= 0 V
—
1.1
–1.5
0.7
–1.5
0.7
400
—
—
480
—
—
–1.0
70
—
0.78
—
—
24
65
1.3
–1.0
0.8
–1.0
0.8
500
2
5
500
5
1
–0.2
100
6
0.87
0.05
–40
40
75
1.5
–0.7
0.9
–0.7
0.9
600
10
—
520
20
—
1.0
145
—
—
0.2
–24
—
85
V
µA
V
µA
V
kHz
%
%
mV
mV
%
µA
V/V
MHz
V
V
µA
µA
%
Condition
Value
Min
—
Typ
—
Max
0.9
Unit
V
(Continued)
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