Texas Instruments AN-1922 LM48511, Руководство пользователя, Страница: 4 / 15

10
1
0.1
0.01
10m 100m 1 5
OUTPUT POWER (W)
T
H
D
+
N
(%
)
SPREAD SPECTRUM
FIXED FREQUENCY
10
0.01
0.1
1
20 200 2k 20k
FREQUENCY (Hz)
T
H
D
+N
(%
)
0.001
SPREAD SPECTRUM, C
IN
= 1
P
F
FIXED FREQUENCY, C
IN
= 1
P
F
SPREAD SPECTRUM,
C
IN
= 180 nF
FIXED FREQUENCY,
C
IN
= 180 nF
10
0.01
0.1
1
20 200 2k 20k
FREQUENCY (Hz)
T
H
D
+N
(%
)
0.001
FIXED FREQUENCY
SPREAD SPECTRUM
10
0.01
0.1
1
20 200 2k 20k
FREQUENCY (Hz)
T
H
D
+N
(%
)
0.001
FIXED FREQUENCY
SPREAD SPECTRUM
Typical Performance Characteristics
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Table 1. LM48511 Demonstration Board Connections (continued)
Designator Function or Use
Set the FB_SEL High for:
PV1 = VFB {1 + [25.5k
Ω
/ 4.87k
Ω
]}
where V
FB
= 1.23V
FB_SEL
Set the FB_SEL Low for:
PV1 = VFB {1 + [25.5k Ω /9.31k Ω ]}
where V
FB
= 1.23V
8 Typical Performance Characteristics
THD+N vs Frequency THD+N vs Frequency
V
DD
= 5V, R
L
= 8 Ω V
DD
= 3.6V, R
L
= 8 Ω
P
O
= 2W, filter = 22kHz, PV
1
= 7.8V P
O
= 500mW, filter = 22kHz, PV
1
= 4.8V
THD+N vs Frequency THD+N vs Output Power
V
DD
= 3V, R
L
= 8 Ω V
DD
= 5V, R
L
= 8 Ω
P
O
= 1.5W, filter = 22kHz, PV
1
= 7V P
O
= 1.5W, f = 1kHz, filter = 22kHz, PV
1
= 7.8V
4 AN-1922 LM48511 Evaluation Board SNAA064C – November 2008 – Revised May 2013
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