Datasheet

TPS54873
SLVS444A − OCTOBER 2002 − REVISED FEBRUARY 2005
www.ti.com
12
PERFORMANCE GRAPHS
Figure 12
50
55
60
65
70
75
80
85
90
95
100
0123456789
V
I
= 5 V,
V
O
= 3.3 V
Efficiency − %
EFFICIENCY
vs
OUTPUT CURRENT
I
O
− Output Current − A
Figure 13
3.28
3.285
3.29
3.295
3.3
3.305
3.31
3.315
3.32
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− Output Voltage − V
OUTPUT VOLTAGE
vs
OUTPUT CURRENT
I
O
− Output Current − A
V
O
Figure 14
3.28
3.285
3.29
3.295
3.3
3.305
3.31
3.315
3.32
4
4.5
5
5.5
6
I
O
= 0
I
O
= 8
I
O
= 4
V
I
− Input Voltage − V
− Output Voltage − V
OUTPUT VOLTAGE
vs
INPUT VOLTAGE
V
O
Figure 15
−20
0
20
40
60
100 1 k 10 k 100 k 1 M
0
45
90
135
180
f − Frequency − Hz
Gain − dB
LOOP RESPONSE
Phase −Degrees
Phase
Gain
V
I
= 5 V,
V
O
= 3.3 V,
I
O
= 6 A,
T
A
= 25°C,
F
S
= 550 kHz
Figure 16
25
35
45
55
65
75
85
95
105
115
125
01234
− Ambient Temperature −
AMBIENT TEMPERATURE
vs
OUTPUT CURRENT
I
O
− Output Current − A
C
°
T
A
567 8
V
I
= 5 V
T
J
= 25°C
f
s
= 700 kHz
Figure 17
Time − 1 µs/div
OUTPUT RIPPLE VOLTAGE
Output Ripple Voltage − 10 mV/div
Fi
g
ure 18
100 µs/div
50 mV/div
LOAD TRANSIENT RESPONSE
V
I
= 5 V,
1A to 5A,
Figure 19
5.0 ms/div
1 V/div
START-UP WAVEFORM
V
O
= 3.3 V
V
I
= 5 V
DETAILED DESCRIPTION