Rainbow Electronics MAX8805Z - Manual (Page 15)

MAX8805Y/MAX8805Z
600mA PWM Step-Down Converters in
2mm x 2mm WLP for WCDMA PA Power
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Input Capacitor Selection
The input capacitor (C IN1 ) of the PA converter reduces
the current peaks drawn from the battery or input
power source and reduces switching noise in the
MAX8805Y/MAX8805Z. The impedance of C
IN1 at the
switching frequency should be kept very low. Ceramic
capacitors with X5R or X7R dielectric are highly recom-
mended due to their small size, low ESR, and small
temperature coefficients. A 2.2µF capacitor is recom-
mended for most applications. For optimum noise
immunity and low input ripple, the input capacitor value
can be increased.
For the LDOs, use an input capacitance equal to the
value of the sum of the output capacitance of LDO1 and
LDO2. Larger input capacitor values and lower ESR pro-
vide better noise rejection and line transient response.
Note that some ceramic dielectrics exhibit large capaci-
tance and ESR variation with temperature. With
dielectrics such as Z5U and Y5V, it may be necessary to
use two times the sum of the output capacitor values of
LDO1 and LDO2 (or larger) to ensure stability at temper-
atures below -10°C. With X7R or X5R dielectrics, a
capacitance equal to the sum is sufficient at all operating
temperatures.
Table 2. Suggested Inductors
MANUFACTURER SERIES
INDUCTANCE
(µH)
ESR
( Ω)
CURRENT RATING
(mA)
DIMENSIONS
(mm)
Coilcraft LPO3310
1.0
1.5
2.2 0.07
0.10
0.13 1600
1400
1100
3.3 x 3.3 x 1.0 = 11mm 3
MIPF2520
1.0
1.5
2.2 0.05
0.07
0.08 1500
1500
1300
2.5 x 2.0 x 1.0 = 5mm 3
MIPS2520
1.3
2.0 0.09
0.11 1500
1200
2.5 x 2.0 x 1.0 = 5mm 3
FDK
MIPF2016
1.0
2.2
0.11 1100 2.0 x 1.6 x 1.0 = 3.2mm 3
Hitachi KSLI-252010
1.5
2.2 0.115
0.080
— 2.5 x 2.0 x 1.0 = 5mm 3
Murata LQH32C_53
1.0
2.2 0.06
0.10 1000
790
3.2 x 2.5 x 1.7 = 14mm 3
Sumida CDRH2D09
1.2
1.5
2.2 0.08
0.09
0.12 590
520
440
3.0 x 3.0 x 1.0 = 9mm 3
CDRH2D11
1.5
2.2
3.3 0.05
0.08
0.10 680
580
450
3.2 x 3.2 x 1.2 = 12mm 3
Taiyo Yuden
CB2518T
2.2
4.7 0.09
0.13 510
340
2.5 x 1.8 x 2.0 = 9mm 3
D3010FB 1.0 0.20 1170 3.0 x 3.0 x 1.0 = 9mm 3
D2812C
1.2
2.2 0.09
0.15 860
640
3.0 x 3.0 x 1.2 = 11mm 3
D310F
1.5
2.2 0.13
0.17 1230
1080
3.6 x 3.6 x 1.0 = 13mm 3
TOKO
D312C
1.5
2.2 0.10
0.12 1290
1140
3.6 x 3.6 x 1.2 = 16mm 3