MAX8830EWET(2007) View Datasheet(PDF) - Maxim Integrated
Part Name
Description
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MAX8830EWET Datasheet PDF : 15 Pages
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LED Light Management IC in
2.5mm x 2.5mm UCSP
Table 7. Suggested Inductors
MANUFACTURER
SERIES
INDUCTANCE
(µH)
Cooper (Coiltronics)
SD3114
2.2
MIPF2520
2.2
FDK
MIPW3226
2.2
TDK
VLF3012AT
2.2
10
TOKO
2.7
DE2812C
10
DCR
(mΩ)
110
80
100
88
360
75
325
ISAT
(A)
1.74
1.3A
1.1
1.0
0.49
1.8
0.78
DIMENSIONS
(LTYP x WTYP x HMAX = VOLUME)
3.0 x 3.0 x 1.45 = 13mm3
2.5 x 2.0 x 1.0 = 5mm3
3.2 x 2.6 x 1.0 = 8mm3
2.8 x 2.6 x 1.2 = 9mm3
3.0 x 3.2 x 1.2 = 12mm3
3.0 x 3.2 x 1.2 = 12mm3
Inductor Selection
The MAX8830 is designed to use a 2.2µH to 10µH
inductor. To prevent core saturation, ensure that the
inductor-saturation current rating exceeds the peak
inductor current for the application. Calculate the worst-
case peak inductor current with the following formula:
IPEAK
=
VOUT × IOUT(MAX)
0.9 × VIN(MIN)
+
VIN(MIN) × 0.5μs
2×L
Table 7 provides a list of suggested inductors.
Capacitor Selection
Bypass the input to GND and PGND using a ceramic
capacitor. A ceramic capacitor with X5R and X7R
dielectrics are recommended for their low ESR and
tighter tolerances over a wide temperature range. Place
the capacitor as close as possible to the IC. The recom-
mended minimum value for the input capacitor is 10µF;
however, larger value capacitors can be used to reduce
input ripple at the expense of size and higher cost.
The output capacitance required depends on the maxi-
mum output current. A 10µF ceramic capacitor works
well in most situations, but a 4.7µF capacitor is accept-
able for lower load currents.
COMP Network Selection
The step-up converter is compensated for stability through
an external compensation network from COMP to GND.
See Table 8 for recommended compensation components.
Table 8. Suggested Compensation
Networks
RCOMP
(kΩ)
CCOMP
(pF)
2.2µH Inductor (Dynamic Loads)
4.3
2200
4.7µH Inductor (Dynamic Loads)
3
4700
10µH Inductor (Dynamic Loads)
3
6800
Only LED Loads (2.2µH to 10µH) 0 (short)
22000
PCB Layout
Due to fast switching waveforms and high-current
paths, careful PCB layout is required. Connect GND
and PGND directly to the ground plane. The IN bypass
capacitor should be placed as close as possible to the
IC. RCOMP and CCOMP should be connected between
COMP and GND as close as possible to the IC.
Minimize trace lengths between the IC and the induc-
tor, the input capacitor, and the output capacitor; keep
these traces short, direct, and wide. The ground con-
nections of CIN and COUT should be as close together
as possible and connected to PGND. The traces from
the input to the inductor and from the output capacitor
to the LEDs may be longer. A sample layout is available
in the MAX8830 evaluation kit.
Pin Configuration
1
+
A
FLED
B
LED2
C
LED1
D
LED4
MAX8830
2
3
4
PGND LX
OUT
LED3 MVON IN
FLEN SCL COMP
GND
SDA
VDD
UCSP
(2.5mm x 2.5mm)
PROCESS: BiCMOS
Chip Information
14 ______________________________________________________________________________________
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