AAT1236 Analogic Corporation, AAT1236 Datasheet - Page 20

• Manufacturer Part Number: AAT1236
• Manufacturer: Analogic Corporation

The output capacitor is selected to maintain the
output load without significant voltage droop
(ΔV
the output diode is not conducting. A ceramic out-
put capacitor from 2.2µF to 4.7µF is recommended
(see Table 6).
Typically, 25V rated capacitors are required for the
24V maximum boost output. Ceramic capacitors
selected as small as 0805 are available which meet
these requirements.
MLC capacitors exhibit significant capacitance reduc-
tion with applied voltage. Output ripple measure-
ments should confirm that output voltage droop and
operating stability are within acceptable limits.
Voltage derating can minimize this factor, but results
may vary with package size and among specific
manufacturers.
20
Manufacturer
Murata
Murata
Murata
Murata
Murata
Manufacturer
Sumida
Sumida
Sumida
Murata
Murata
Taiyo Yuden
Taiyo Yuden
Coiltronics
Coiltronics
Coiltronics
OUT
) during the power switch ON interval, when
Table 5: Typical Surface Mount Inductors for Various Output Loads (select I
CDRH4D22/HP-2R2
LQH55DN2R2M03
CDR4D11/HP-2R4
LQH662N2R2M03
CDRH4D18-2R2
Part Number
NR4018T2R2
NR3015T2R2
SD3814-2R2
SD3114-2R2
SD3112-2R2
GRM21BR71E225KA73L
GRM21BR71A225KA01
GRM21BR61E475KA12
GRM219R61E225KA12
GRM188R60J225KE19
Part Number
Table 6: Recommended Ceramic Capacitors.
Inductance
(µH)
2.2
2.4
2.2
2.2
2.2
2.2
2.2
2.2
2.2
2.2
Value (µF)
Max DC I
2.2
2.2
2.2
2.2
4.7
Current (A)
High Efficiency White LED Drivers
Output capacitor size can be estimated at a switch-
ing frequency (F
To maintain stable operation at full load, the output
capacitor should be selected to maintain ΔV
between 100mV and 200mV.
The boost converter input current flows during both
ON and OFF switching intervals. The input ripple
current is less than the output ripple and, as a
result, less input capacitance is required.
2.50
1.70
1.32
3.30
3.20
2.70
1.48
1.90
1.48
1.12
SAT
Voltage Rating
for Backlight and Keypad
6.3
DCR
10
25
25
25
105
140
(Ω Ω )
35
75
19
29
60
60
77
86
S
C
) of 500kHz (worst case):
OUT
Size (mm)
=
5.0x5.0x2.4
4.8x4.8x1.2
5.0x5.0x2.0
6.3x6.3x4.7
5.0x5.7x4.7
4.0x4.0x1.8
3.0x3.0x1.5
3.8x3.8x1.4
3.1x3.1x1.4
3.1x3.1x1.2
LxWxH
I
F
OUT
Temp Co
S
· ΔV
X5R
X7R
X5R
X7R
X5R
· D
PEAK
MAX
OUT
< I
Non-Shielded
Case Size
1236.2007.01.1.0
SAT
Shielded
Shielded
Shielded
Shielded
Shielded
Shielded
Shielded
Shielded
Shielded
Type
0603
0805
0805
0805
0805
).
OUT