Step Down DC - DC Converter Power IC
MD1322N
Feature
Block Diagram
Output adjustable Remote On/Off
Fixed Frequency 250kHz PWM Control
Over Current Protection
Under Voltage Lockout
Thermal Shut Down
Remote On / Off
Input Voltage range 8V to 30V
Maximum Output Current 1.8A
Included main switch MOSFET and fly wheel SBD
Adjustable output from 2.5V to 12V with external resistors
High Efficiency typ. 92% (at:Vin=8V, Vout=5V, Iout=0.5A)
R/C
5
Vref
28
Vcc
6
Vboot
8
V
B
25
V
G
23
V
DD
18∼21
ON／OFF
Control
UVLO
START =7.2V
STOP =6.7V
Boot
Vref=6.5V
HighSide
Vref=V
OUT
+5.8V
Bandgap Reference
Vref=5.0V±5％
TSD
100゜
C
150゜
C
Main Switch
MOS OFF
HighSide
Driver
Error Amp
V
OUT
PWM Comp
11∼14
−
＋
2.45V
＋
−
3V
1V
OSC
f＝250kHz
Q
R
S
＋
−
CLM Vth=
0.1∼0.2V
32
30
1
2
3
4,26
16
amp-
ampOUT
S/S
OCL
−
OCL
＋
GND
P.GND
※ N/C : 7,9,10,15,17,22,24,29,31
Standard Connection Diagram
Pin Assignment ( SSOP32)
INPUT
8∼30V
18∼21
8
25
11∼14
OUTPUT
2.5∼12V
3
6
2
30
5
32
＋
MD1322N
＋
1
ON
28
4,26
16
S/S
OCL−
OCL＋
GND
R/C
Vcc
N/C
Vboot
N/C
N/C
V
OUT
V
OUT
V
OUT
V
OUT
N/C
P.GND
1
2
3
32
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
4
5
6
7
8
9
10
11
12
13
14
15
16
amp−
N/C
ampOUT
N/C
Vref
VTS
GND
V
B
N/C
V
G
N/C
V
DD
V
DD
V
DD
V
DD
N/C
SHINDENGEN
MD1322N
P □□□□□
GND
GND
*Please consult with us when it is desired to make
output adjustable in a range over 5.3V.
(See
the marking specification for the indication on the device)
U097−2
15
MD1322N
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）
OCL-,OCL
+
input voltage
Remote control voltage
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
OCL
V
RC
PD
Ta- ope
Tstg
Tj
θja
θ j c
※2
32
32
1.8
2.3
5.5
5.5
2.5
−30 to 85
−40 to 150
150
50
20
V
V
A
A
V
V
W
℃
℃
℃
℃/W
℃/W
（Top Side）
，82.1％
（Bottom Side）
，Those with through-hole.
※1 Glass-Epoxy Board：56×39mm
2
，Thickness：1mm，Copper Pattern Rate：87.1％
※2 The measurement result in the center of case.
Recommended Operating Conditions
Item
Symbol
Recommendation
Units
Junction temperature
Input voltage Ta＝−10℃ to 85℃）
（
Input voltage Ta＝−30℃ to −10℃）
（
Output voltage setting range
※3 Input voltage at the time of power supply operation.
Tj
V
i
V
i
V
O
※3
※3
※4
−30
8
8.5
2.5
to
to
to
to
125
30
30
12
℃
V
V
V
※4 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 V
DSS
＿
Ｈ
I
DSS
＿
Ｈ
Zero gate voltage drain current
Static drain-source on-state resistance R
ON
＿
Ｈ
Source-drain diode forward voltage
V
SD
＿
Ｈ
Low Side SBD
Maximum reverse voltage
V
RM
V
F
Forward voltage
I
R
Reverse current
Control IC
Undervoltage lockout threshold (start) Vcc＿start
Undervoltage lockout threshold (stop) Vcc＿stop
Undervoltage lockout hysteresis Vcc＿hys
Supply ½
urrent
Icc
Supply current-remote OFF state Icc＿off
Remote control ON input voltage V
RC
＿on
Remote control OFF input voltage V
RC
＿off
I
RC
Remote control source current
Bootstrap voltage
Vboot
Vref
Reference voltage
fosc
Initial frequency accuracy
Threshold of over current limit Vth＿OCL
Softstart source current
I
S
/
S
Error amp reference voltage
Vamp
T＿TSD
Thermal shutdown temperature
I
D
＝1mA,V
GS
＝0V
V
DS
＝32V,V
GS
＝0V
I
D
＝1.2A,V
GS
＝4V
I
S
＝1.2A,V
GS
＝0V
−
I
F
＝1.2A
V
R
＝V
RM
−
−
−
Vcc＝8 to 30V
Vcc＝8 to 30V
Vcc＝8 to 30V
Vcc＝8 to 30V
Vcc＝8 to 30V
Vcc＝24V
Vcc＝8 to 30V
Vcc＝24V
Vcc＝24V
Vcc＝24V
Vcc＝8 to 30V
−
32
−
−
−
40
−
−
−
−
140
−
−
−
−
−
10
250
1.5
−
0.55
2
V
μ
A
mΩ
V
V
V
mA
V
V
V
mA
mA
V
V
μ
A
V
V
kHz
V
μ
A
V
℃
U097−2
6.5
7.2
7.9
6.7
7.4
6.0
0.5
−
−
10
13
−
1.2
1.5
−
0.45
−
−0.2
5.3
−
2.5
−
250
−
6.5
7.6
5.4
4.75
5.25
5
212.5
287.5
250
0.162 0.19 0.218
−20 −12.5
−5
2.4
2.45
2.5
−
150
−
16
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