ltc1876eg-trpbf Linear Technology Corporation, ltc1876eg-trpbf Datasheet - Page 33

• Manufacturer Part Number: ltc1876eg-trpbf
• Description: High Efficiency, 2-phase, Dual Synchronous Step-down Switching Controller And Step-up Regulator
• Manufacturer: Linear Technology Corporation

APPLICATIO S I FOR ATIO
An embarrassing problem, which can be missed in an
otherwise properly working switching regulator, results
when the current sensing leads are hooked up backwards.
The output voltage under this improper hookup will still be
maintained but the advantages of current mode control
TYPICAL APPLICATIO S
400mA
V
OUT3
5V
10 F
0.01 F
220pF
16V
220pF
0.1 F
5R
6.8k
6.8k
20k
20k
10k
1%
1%
31.6k
U
+
42.5k
0.01 F
470pF
470pF
1%
25k
1%
10 F
20V
D5
U
1000pF
1000pF
3.3V
OUT
U
10
11
12
13
14
15
16
17
18
W
Low Voltage 3.3V to 1.8V, 2.5V and 5V Power Supply
1
2
3
4
5
6
7
8
9
RUN/SS1
SENSE1
SENSE1
V
FREQSET
STBYMD
FCB
I
SGND
3.3V
I
V
SENSE2
SENSE2
AUXSGND
AUXV
AUXSW
AUXSW
TH1
TH2
OSENSE1
OSENSE2
OUT
FB
L3, 5.4 H
LTC1876
+
–
–
+
AUXPGND
AUXPGND
RUN/SS2
BOOST1
BOOST2
EXTV
AUXV
PGOOD
INTV
AUXSD
U
PGND
SW1
SW2
TG1
BG1
BG2
TG2
V
CC
CC
IN
IN
36
35
34
33
32
31
30
29
28
27
26
25
24
23
22
21
20
19
SHUTDOWN
PGOOD
1 F
will not be realized. Compensation of the voltage loop will
be much more sensitive to component selection. This
behavior can be investigated by temporarily shorting out
the current sensing resistor—don’t worry, the regulator
will still maintain control of the output voltage.
100k
D3
D4
0.1 F
0.1 F
1 F
+
0.1 F
4.7 F
10
0.1 F
V
3.3V
IN
M3
M1
6.3V, SP
33 F
2 H
2 H
L1
L2
3
3
1
M2
M4
1
R
0.008
0.008
R
SENSE
SENSE
47 F
47 F
6.3V
6.3V
D2
D1
SP
SP
2
2
+
+
4
4
1876 TA02
LTC1876
V
2.5V
4A
M1, M2, M3, M4: FDS6912A
L1, L2: SUMIDA CEP123-2RO
L3: SUMIDA CDRH5D18
D1, D2: MBRM140T3
D3, D4: BAT54A
D5: MBR0520
OUT1
V
1.8V
5A
OUT2
33
1876fa