ADP3050-3.3 Analog Devices, ADP3050-3.3 Datasheet - Page 11

• Manufacturer Part Number: ADP3050-3.3
• Description: 200 Khz, 1 a Step-down High-voltage Switching Regulator
• Manufacturer: Analog Devices

2. Decide what type of capacitor to use (tantalum, ceramic,
3. Check the capacitor voltage rating and ripple current rating
4. Make sure the final choice for the output capacitor has been
CATCH DIODE SELECTION
The recommended catch diode is a type 1N5818 Schottky or an
equivalent. The low forward voltage drop (450 mV typical at 1 A)
and fast switching speed of a Schottky rectifier provide the best
performance and efficiency. The 1N5818 is rated at 30 V reverse
etc.), then look at the table for some possible devices. Many
more values, sizes, and voltage ratings are available, so contact
each manufacturer for a complete product list. If a certain type
of capacitor must be used and space permits, simply use
several devices in parallel to reduce the total ESR.
to ensure it will work for your application (these ratings are
derated for higher temperatures, so always check the
manufacturer’s data sheet).
optimized for cost, size, availability, and performance while
still meeting the required capacitance. The recommended
capacitance is in the 47 µF to 220 µF range.
Vendor/
Series
AVX
Sprague
Tokin
Company
AVX
Kemet
Murata (USA)
Nemco
Sprague
Tokin (USA)
Tokin (Japan)
Taiyo Yuden (USA)
Taiyo Yuden (Japan)
Maximum ESR ratings at 100 kHz; MLC = multilayer ceramic.
TPS
TPS
TPS
TPS
Y5V
Y5V
Y5V
Y5V
593D
593D
593D
593D
CU
CU
CU
CU
CU
Value
( F)
100
47
100
100
10
10
18
22
47
68
100
100
10
10
18
10
22
Phone
[phone]
[phone]
[phone]
[phone]
[phone]
[phone]
81-22-211-1281
[phone]
81-33-833-5441
ESR
( )
0.150
0.150
0.100
0.125
~0.040
~0.040
~0.040
~0.040
0.150
0.150
0.100
0.100
~0.040
~0.040
~0.040
~0.040
~0.030
Table III. Capacitor Selection Guide
Table IV. Capacitor Manufacturers
Fax
[phone]
[phone]
[phone]
[phone]
[phone]
[phone]
81-22-211-0975
[phone]
81-33-835-4754
Max
Voltage
(V)
6.3
16
10
16
10
16
10
10
16
16
10
16
10
25
25
50
25
voltage and 1 A average forward current. For lower input voltages,
use a lower voltage Schottky to reduce the diode forward voltage
drop and increase overall system efficiency (i.e., a 12 V to 5 V
system does not need a 30 V diode). For automotive applications,
a 60 V Schottky may be necessary. The average forward current for
the catch diode can be calculated by:
For the earlier continuous mode example (12 V to 5 V at 800 mA),
the average diode current would be:
For this system, a 1N5817 would be a good choice (rated at 20 V
and 1 A). Do not use catch diodes rated less than 1 A. Even though
the average current can be less than 1 A under normal operating
conditions, since the diode current will be much higher under fault
conditions. The worst case fault condition for the diode occurs when
the regulator becomes slightly overloaded (sometimes called a soft
Web Address
www.avxcorp.com
www.kemet.com
www.murata.com
www.nemcocaps.com
www.vishay.com
www.tokin.com
www.tokin.com
www.t-yuden.com
www.t-yuden.com
Type
Tantalum
Tantalum
Tantalum
Tantalum
MLC
MLC
MLC
MLC
Tantalum
Tantalum
Tantalum
Tantalum
MLC
MLC
MLC
MLC
MLC
I
I
DIODE(AVG)
DIODE
(AVG)
=
=
0 8
I
.
OUT
Package
Dimensions (mm)
W
3.2
4.3
4.3
4.3
1.6
2.5
2.5
2.5
4.3
4.3
4.3
4.3
1.6
2.7
5.0
5.0
5.0
×
12 5
×
12
V
–
IN
V
–
IN
=
L
6.0
7.3
7.3
7.3
3.2
3.2
3.2
3.2
7.3
7.3
7.3
7.3
3.2
5.7
5.7
5.7
5.7
V
0 47
OUT
.
ADP3050
A
H
2.6
2.9
2.9
2.9
1.5
1.7
1.7
1.7
2.8
2.8
2.8
4.0
1.6
2.5
2.5
3.0
3.0
(5)