2.5V-12V
Output MD1422N
14.1MAX
13.6
32
Company Name
+ 0.1
–
Dimensions = mm
DESCRIPTION
The MD1422N is a high-efficiency step down DC-DC converter
power integrated circuit with main MOSFET switch and synchronous
17
SHINDENGEN
M D1 4 2 2 N
5038N
+ 0.1
7.5
–
+
Type No.
9.95
– 0.3
rectification MOSFET. The MD1422N can deliver high efficiency over
a wide input voltage range. This device has output voltage digitally
selectable from 2.5V to 12V. With the MD1422N you can construct a
complete DC-DC converter using only a few external components.
1
(0.8)
0.8
0.35
– 0.1
+
16
Featuring an SSOP 32-pin surface mount package, the MD1422N
Lot No.
allows you to incorporate a very small and thin power supply on your
circuit board.
0.16 M
BLOCK DIAGRAM
Vref
28
FEATURES
Vboot
8
Vcc
6
V
B
25
V
G
23
V
DD
18~21
"
High efficiency
"
Wide input voltage load range
8VDC to 40VDC
Up to 3ADC
R/C
5
ON/OFF
circuit
UVLO
START = 7.2V
STOP = 6.7V
BOOT Reference
Vref=6.5V
High side
Vref=Vout+5.8V
100˚C
Reference
Vref=5V+5%
–
150˚C
High-Low MOS
synchro-OFF
High side
Driver
TSD
"
Output voltage selectable function
V
OUT
11~14
Error amp
2.5V to 12V
"
Internal Switching power device
Main MOSFET for switch and
–
+
2.45V
PWM Comp
+
–
3V
1V
OSC
f=250kHz
Q
R
S
High-Low MOS
synchro-ON Prevention
Low side
Vref=6.5V
Low side
Driver
+
–
CLM Vth=
0.1~0.2V
synchronous rectification MOSFET
"
Fixed 250kHz PWM frequency
P.GND
16
(Without external resistor and capacitor)
"
Overcurrent protection
"
Thermal shutdown function
"
Remote control ON/OFF
32
30
1
2
3
4,26
9
amp–
ampOUT
S/S
OCL– OCL+
GND
V
GL
PIN ASSIGNMENT
Pin#
1
2
3
4
5
6
7
8
9
10
11 ~ 14
15
16
17
18 ~ 21
22
23
24
25
26
27
28
29
Symbol
S/S
OCL-
OCL+
GND
R/C
Vcc
N/C
Vboot
V
GL
N/C
V
OUT
N/C
P.GND
N/C
V
DD
N/C
V
GH
N/C
V
B
GND
VTS
Vref
N/C
Function description
Capacitor for softstart
Overcurrent protection (OCL) (-)
Overcurrent protection (OCL) (+)
Signal GND
Remote ON/OFF control terminal
Input voltage
Non-connection
High side drive supply for main MOS
Low side MOSFET gate terminal
Non-connection
Power stage output
Non-connection
Power GND
Non-connection
Drain of main MOS Switch
Non-connection
Main switch high side MOSFET gate terminal
Non-connection
Bootstrap capacitor between VB and VOUT
Signal GND
Output voltage selectable terminal
Internal voltage reference
Non-connection
30
31
32
AmpOUT
N/C
amp-
Error Amp out
Non-connection
Error Amp (-) input
S/S : 1
OCL– : 2
OCL+ : 3
GND : 4
R/C : 5
V
CC
: 6
N/C : 7
Vboot : 8
V
GL
: 9
N/C : 10
V
OUT
: 11
V
OUT
: 12
V
OUT
: 13
V
OUT
: 14
N/C : 15
P.GND : 16
32 : amp-
31 : N/C
30 : ampOUT
29 : N/C
28 : Vref
27 : VTS
26 : GND
25 : V
B
24 : N/C
23 : V
GH
22: N/C
21: V
DD
20: V
DD
19: V
DD
18 : V
DD
17 : N/C
"
Vref
- Temperature compensated internal voltage. You can pull 1mA
maximum for external circuit.
"
OSC
- MCD1422N uses internal oscillator without external component.
Frequency (Saw tooth wave form) is trimmed to 250kHz on chip.
"
Error Amp
- Error Amp detects output voltage of DC-DC converter
and controls PWM signal. You can adjust the loop gain when you
connect feedback resistor and capacitor between AmpOUT and
Amp (-). It will provide stable phase compensation.
"
Overcurrent protection
- MD1422N uses pulse-by-pulse current
protection. Current will be sensed voltage drop of external current
sensing resistor. Threshold of OCL is 0.19V.
1 - 8 0 0 - 6 3 4 - 3 6 5 4
SHINDENGEN [ SHINDENGEN ELECTRIC MFG.CO.LTD ]
