Rainbow Electronics MAX1692 - Manual (Page 10)

MAX1692
Low-Noise, 5.5V-Input,
PWM Step-Down Regulator
10 ______________________________________________________________________________________
Bypass Considerations
Bypass IN and OUT to PGND with 10µF and 47µF,
respectively. Bypass BP and REF to GND with 0.1µF
and 0.22µF, respectively. Locate the bypass capacitors
as close as possible to their respective pins to minimize
noise coupling. For optimum performance, place input
and output capacitors as close to the device as feasi-
ble (see
Capacitor Selection section).
PC Board Layout and Routing
High switching frequencies and large peak currents
make PC board layout a very important part of design.
Good design minimizes excessive EMI on the feedback
paths and voltage gradients in the ground plane, both
of which can result in instability or regulation errors.
Connect the inductor, input filter capacitor, and output
filter capacitor as close together as possible, and keep
their traces short, direct, and wide. Connect their
ground pins at a single common node in a star-ground
configuration. The external voltage-feedback network
should be very close to the FB pin, within 0.2in (5mm).
Keep noisy traces, such as from the LX pin, away from
the voltage-feedback network; also keep them sepa-
rate, using grounded copper. Connect GND and PGND
at the highest quality ground. The MAX1692 evaluation
kit manual illustrates an example PC board layout and
routing scheme.
FAX COMPANY
Coilcraft 847-639-6400
PHONE
AVX 843-946-0238
847-639-1469
843-626-3123
Coiltronics 561-241-7876 561-241-9339
Kemet 408-986-0424 408-986-1442
Table 2. Suggested Capacitors
Nihon
USA 805- 867-2555
Japan 81-3-3494-7411 805- 867-2698
81-3-3494-7414
Sanyo
USA 619-661-6835
Japan 81-7-2070-6306 619-661-1055
81-7-2070-1174
Sprague 603-224-1961 603- 224-1430
Sumida
USA 847-956-0666
Japan 81-3-3607-5111 847- 956-0702
81-3-3607-5144
Taiyo Yuden 408-573-4150 408-573-4159
TDK 847-390-4373 847-390-4428
Table 1. Suggested Inductors Table 3. Component Suppliers
SUGGESTED
INDUCTORS
OUTPUT
VOLTAGE
RANGE
(V)
INDUCTOR L
VALUE
(µH)
1.25 to 2.5 10
Sumida CD43-100
Coilcraft D01608C-103
Sumida CD54-100
TDK NLC322522-100T
2.5 to 4.0 22
Sumida CD43-220
Sumida CD54-220
4.0 to 5.5 33
Sumida CD43-330
Sumida CD54-330
ESR
(m
Ω
)
Sanyo
6TPA47M
MANUFACTURER
PART NUMBER
AVX
TPSD476M016R0150
100
150
Sprague
594D686X9010C2T
95
Taiyo Yuden
JMK325BJ106MN
50
Poscap
TYPE
Tantalum
Tantalum
Ceramic