Step Down DC - DC Converter Power IC
MD3221R
Feature
Block Diagram
V
cc
18
Small
footprint
Output
adjustable
Remote
On/Off
Synchronous
Rectification
5V Input
Input Voltage range 4.5V to 20V
Maximum Output Current 3A
Built_in MOSFETs for main switch and synchronous rectification
Adjustable output from 0.8V to 14V with external resistors
High Efficiency typ. 96% (at:Vin=5V, Vout=3.3V, Iout=1A, f=100kHz)
100kHz / 300kHz selectable switching frequency
Over Current Protection
Under Voltage Lockout
Thermal Shut Down
Remote On / Off
Supply current at remote off 25μA typ.
V
ref
15
V
boot
19
V
B
8
V
GH
7
V
DD
3∼6
R/C
14
（L.Active）
ON/OFF
Control
V
ref
Bandgap
Reference
1.26V±1％
Thermal
Shutdown
＋
−
＋
−
−
V
CC
＋
UVLO
Current
Limit1
Latch
Q R S
＋
−
V
OUT
1,2,22∼25
S/S
13
＋
−
S R Q
Latch
INVL
ampOUT
11
Error Amp
amp-
12
＋
＋
−
PWM Comp
−
＋
OSC
＋
−
Current
Limit2
S R Q
Latch
9,17
16
10
20
21
26
GND
OSC
VTS
P.GND1
V
GL
P.GND2
Standard Connection Diagram
wiring for f=300kHz
Pin Assignment ( LSSOP26 )
INPUT
4.5∼20V
3∼6
19
8
1,2,22∼25
OUTPUT
0.8∼14V
18
14
MD3221R
10
12
＋
13
＋
11
15
ON
16
20
9,17 26
V
OUT
V
OUT
V
DD
V
DD
V
DD
V
DD
V
GH
V
B
GND
VTS
ampOUT
amp-
S/S
1
26
2
3
4
5
6
7
8
9
10
11
12
13
25
24
23
22
21
20
19
18
17
16
15
14
P.GND2
V
OUT
V
OUT
V
OUT
V
OUT
V
GL
P.GND1
V
boot
V
CC
GND
OSC
Vref
R/C
SHINDENGEN
MD3221R
P □□□□□
GND
GND
(See
the marking specification for the indication on the device)
U097−2
7
MD3221R
Absolute Maximum Ratings
Item
Symbol
Unless otherwise specified : Ta=25ºC
Ratings
Units
Input/Output Ratings
Input voltage
Main MOSFET input voltage
Output current
（ave）
Output current
（peak）
Input voltage between V
B
and V
OUT
Vboot sink current
Remote control voltage
OSC input voltage
Amp- input voltage
Vref sink current
Thermal Ratings
Power dissipation max
※ 1
Operating temperature
Storage temperature
Junction temperature
Thermal resistance
※ 1
V
CC
V
DD
I
OUT
a v e
I
OUT
p e a k
V
B
Iboot
V
RC
V
OSC
Vamp-
Iref
P D 1
※3
P D 2
※3
Ta- ope
Tstg
Tj
θ j a 1
※3
θ j a 2
※3
θ j c 1
※2 , ※3
θ j c 2
※2 , ※3
22
22
3
4
5.5
−30
V
CC
Vref
Vref
−3
1.1
1.5
−30 to 85
−40 to 150
150
110
87
55
30
V
V
A
A
V
mA
V
V
V
mA
W
W
℃
℃
℃
℃/W
℃/W
℃/W
℃/W
※1 CEM-3 Board：50.8×50.8mm
2
，Thickness：1mm，Copper Pattern：300mm
2
（Top Side）
，There is no through-hole.
※2 The measurement result in the center of case.
※3 PD1,θja1,θjc1 are the values of the power dissipation and thermal registance when electifying to a single internal element.
PD2,θja2,θjc2 are the values of the power dissipation and thermal registance when electifying to two internal element.
Recommended Operating Conditions
Item
Symbol
Recommendation
Units
Junction temperature
Input voltage
Output voltage setting range
Tj
V
i
V
O
※4
※5
−30 to 125
4.5 to 20
0.8 to 14
℃
V
V
※4 Input voltage at the time of power supply operation.
※5 Output voltage at the time of power supply operation.
Electrical Characteristics
Item
Symbol
Condition
Unless otherwise specified : Ta=25ºC
MIN
TYP
MAX
Units
High Side MOSFET
Drain-source breakdown voltage
Zero gate voltage drain current
Static drain-source on-state resistance
Source-drain diode forward voltage
Low Side MOSFET
Drain-source breakdown voltage
Zero gate voltage drain current
Static drain-source on-state resistance
Source-drain diode forward voltage
Control IC
Supply ½
urrent (f=100kHz)
Supply ½
urrent (f=300kHz)
Supply current at remote OFF
Undervoltage lockout threshold (start)
Undervoltage lockout hysteresis
Bootstrap voltage
Line regulation
Load regulation
Reference voltage
Line regulation
Load regulation
Initial frequency1 accuracy
Initial frequency2 accuracy
Maximum duty cycle
Remote control ON input voltage
Remote control OFF input voltage
Remote control source current
Soft-start source current
Error amplifier reference voltage
Threshold of over current limit at Ron detection
Timer current
Soft-start input voltage before timer starting
Threshold of latch
Output voltage accuracy (Vo=0.8V)
Thermal shutdown temperature
V
DSS
＿
H
I
DSS
＿
H
R
ON
＿
H
V
SD
＿
H
V
DSS
＿
L
I
DSS
＿
L
R
ON
＿
L
V
SD
＿
L
Icc＿
L
Icc＿
H
Icc＿off
Vcc＿start
Vcc＿hys
Vboot
V
B
-IN
V
B
-L
Vref
REG-IN
REG-L
fosc＿1
fosc＿2
Dty＿max
V
R/C
＿ON
V
R/C
＿OFF
I
RC
Is
/
s
Vamp
Ith＿OCL1
Itimer
Vs
/
s
Vth＿lat
V
F/B
＿
1
T＿TSD
I
D
＝1
m
A, V
GS
＝0V
V
DS
＝22V,V
GS
＝0V
I
D
＝1.2A,V
GS
＝4.5V
I
S
＝1.2A,V
GS
＝0V
I
D
＝1
m
A ,V
GS
＝0V
V
DS
＝22V,V
GS
＝0V
I
D
＝1.2A,V
GS
＝4.5V
I
S
＝1.2A,V
GS
＝0V
Vcc＝4.5V to 20V
Vcc＝4.5V to 20V
Vcc＝4.5V to 20V
−
−
Vcc＝5V
Vcc＝4.5V to 20V
Vcc＝5V
Vcc＝5V
Vcc＝4.5V to 20V
Vcc＝5V
Vcc＝5V
Vcc＝5V
Vcc＝5V
Vcc＝5V
Vcc＝5V
Vcc＝5V
Vcc＝5V
Vcc＝5V
Vcc＝5V
Vcc＝5V
Vcc＝5V
Vcc＝5V
Vcc＝4.5V to 20V
−
22
−
−
−
22
−
−
−
−
−
−
4.1
0.4
3.84
−
−
3.84
−
−
85
255
85
−0.2
2
−
−3
0.784
3
−40
2.75
3.3
0.784
−
−
−
22
−
−
−
22
−
3.3
5
25
4.3
0.5
4
−
−
4
−
−
100
300
90
−
−
2
−2.5
0.8
−
−33
2.9
3.45
0.800
140
−
10
55
1.5
−
10
55
1.5
3.9
5.9
50
4.5
0.6
4.16
30
30
4.16
30
30
115
345
95
0.7
Vcc
10
−2
0.816
−
−26
3.05
3.6
0.816
−
V
μ
A
mΩ
V
V
μ
A
mΩ
V
mA
mA
μ
A
V
V
V
mV
mV
V
mV
mV
kHz
kHz
%
V
V
μA
μA
V
A
μA
V
V
V
℃
8
U097−2
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