2 .5 V-1 2 V Output MD1422N
14.1MAX
Dimensions = mm
DES CRIP TION
13.6 +
0.1
–
The MD1422N is a high-efficiency step down DC-DC converter
power integrated circuit with main MOSFET switch and synchronous
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.
Featuring an SSOP 32-pin surface mount package, the MD1422N
allows you to incorporate a very small and thin power supply on your
circuit board.
32
17
Company Name
Type No.
SHINDENGEN
MD1422N
5038N
1
16
0.16
Lot No.
M
+
0.1
0.35 –
(0.8)
0.8
BLOCK DIAGRAM
FEATURES
ꢀ
High efficiency
Vcc
VG
VDD
Vref
VB
25
Vboot
8
18~21
23
28
6
ꢀ
Wide input voltage load range
8VDC to 40VDC
R/C
UVLO
START = 7.2V
STOP = 6.7V
High side
Vref=Vout+5.8V
ON/OFF
circuit
BOOT Reference
Vref=6.5V
5
Up to 3ADC
100˚C 150˚C
High side
Driver
Reference
High-Low MOS
synchro-OFF
ꢀ
ꢀ
Output voltage selectable function
2.5V to 12V
TSD
+
Vref=5V 5%
–
Error amp
VOUT
11~14
PWM Comp
–
+
High-Low MOS
synchro-ON Prevention
Internal Switching power device
Main MOSFET for switch and
synchronous rectification MOSFET
Fixed 250kHz PWM frequency
(Without external resistor and capacitor)
Overcurrent protection
+
–
Low side
Vref=6.5V
3V
1V
2.45V
Low side
Driver
Q
OSC
f=250kHz
+
–
R
S
ꢀ
P.GND
16
CLM Vth=
0.1~0.2V
ꢀ
ꢀ
ꢀ
32
amp–
30
1
2
3
OCL– OCL+
4,26
GND
9
ampOUT
S/S
VGL
Thermal shutdown function
Remote control ON/OFF
P IN AS S IGNMENT
30
31
32
AmpOUT
N/C
Error Amp out
P in #
S ym b o l
Fu n c t io n d e s c rip t io n
Capacitor for softstart
Non-connection
Error Amp (-) input
1
S/S
OCL-
OCL+
GND
R/C
amp-
2
Overcurrent protection (OCL) (-)
Overcurrent protection (OCL) (+)
Signal GND
3
4
S/S : 1
OCL– : 2
OCL+ : 3
GND : 4
R/C : 5
VCC : 6
N/C : 7
Vboot : 8
VGL : 9
N/C : 10
VOUT: 11
VOUT: 12
VOUT: 13
VOUT: 14
N/C : 15
32 : amp-
31 : N/C
30 : ampOUT
29 : N/C
28 : Vref
27 : VTS
26 : GND
25 : VB
24 : N/C
23 : VGH
22: N/C
21: VDD
20: VDD
19: VDD
18 : VDD
17 : N/C
5
Remote ON/OFF control terminal
Input voltage
6
Vcc
7
N/C
Non-connection
8
Vboot
VGL
High side drive supply for main MOS
Low side MOSFET gate terminal
Non-connection
9
10
11 ~ 14
15
16
17
18 ~ 21
22
23
24
25
26
27
28
29
N/C
VOUT
N/C
Power stage output
Non-connection
P.GND
N/C
Power GND
P.GND : 16
Non-connection
VDD
Drain of main MOS Switch
Non-connection
ꢀ Vref - Temperature compensated internal voltage. You can pull 1mA
N/C
maximum for external circuit.
VGH
Main switch high side MOSFET gate terminal
Non-connection
ꢀ OSC - MCD1422N uses internal oscillator without external component.
N/C
Frequency (Saw tooth wave form) is trimmed to 250kHz on chip.
VB
Bootstrap capacitor between VB and VOUT
Signal GND
ꢀ 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.
GND
VTS
Vref
N/C
Output voltage selectable terminal
Internal voltage reference
Non-connection
ꢀ 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