Typical Application - Analog Devices DC2874A-A Demo Manual

DEMO MANUAL DC2874A-A/
DC2874A-B/DC2874A-C

TYPICAL APPLICATION

1µF 47µF 0.22µF
10k
390pF
1µF 47µF 0.22µF
L = COILCRAFT,XEL4030-101ME
Conducted EMI Performance
(CISPR25 Conducted Emission Test with Class 5 Peak Limits)
60
50
40
30
20
10
0
–10
–20
0 10 20 30 40
FREQUENCY (MHz)
DC2874A–A 4–PHASE DEMO BOARD
(WITH EMI FILTER INSTALLED)
3.3V INPUT TO 1.2V OUTPUT AT 32A, f
Radiated EMI Performance
(CISPR25 Radiated Emission Test with Class 5 Peak Limits)
60
VERTICAL POLARIZATION
50
40
30
20
10
0
–10
–20
0 100 200 300 400
FREQUENCY (MHz)
DC2874A–A 4–PHASE DEMO BOARD
(WITH EMI FILTER INSTALLED)
3.3V INPUT TO 1.2V OUTPUT AT 32A, f
2
V
IN
2.25V TO 5.5V
V
IN
EN PGOOD
100nH
MODE/SYNC SW
LTC3310S
ITH FB
RT
SSTT AGND PGND
274K
0.1µF
V
IN
V
IN
EN PGOOD
100nH
MODE/SYNC SW
V
IN
LTC3310S
FB
ITH
AGND PGND RT
CLASS 5 PEAK LIMIT
MEASURED EMISSIONS
AMBIENT NOISE
50 60 70 80 90 100 110
= 2MHz
SW
CLASS 5 PEAK LIMIT
MEASURED EMISSIONS
AMBIENT NOISE
500 600 700 800 900 1000
= 2MHz
SW
0.22µF
47µF
V
OUT
1.2V
6.8pF
140k
22µF
x2
10µF
x2
100k
47µF
0.22µF
22µF
x2
10µF
x2
Radiated EMI Performance
(CISPR25 Radiated Emission Test with Class 5 Peak Limits)
60
HORIZONTAL POLARIZATION
50
40
30
20
10
0
–10
–20
0 100 200
DC2874A–A 4 PHASE DEMO BOARD
(WITH EMI FILTER INSTALLED)
3.3V INPUT TO 1.2V OUTPUT AT 32A, f
VOUT Ripple
VOUT Ripple
(I = 40A)
(I = 40A)
OUT
OUT
V
OUT
10mV/DIV
100
95
90
85
80
75
70
65
60
55
50
0 5 10 15 20
I (A)
OUT
CLASS 5 PEAK LIMIT
MEASURED EMISSIONS
AMBIENT NOISE
300 400 500 600 700 800
FREQUENCY (MHz)
= 2MHz
SW
100ns/DIV
4 PHASE
3 PHASE
2 PHASE
25 30 35 40
900 1000
Rev. 0