Datasheet

LT3467/LT3467A
11
3467afe
APPLICATIONS INFORMATION
Using the circuit of Figure 2 as an example, the following
table shows the parameters used to generate the Bode
plot shown in Figure 7.
Table 3. Bode Plot Parameters
PARAMETER VALUE UNITS COMMENT
R
L
10.4 Ω Application Specifi c
C
OUT
15 μF Application Specifi c
R
ESR
10 mΩ Application Specifi c
R
O
0.4 MΩ Not Adjustable
C
C
60 pF Not Adjustable
C
PL
3.3 pF Adjustable
R
C
100 kΩ Not Adjustable
R1 402 kΩ Adjustable
R2 133 kΩ Adjustable
V
OUT
5 V Application Specifi c
V
IN
3.3 V Application Specifi c
g
ma
35 μmho Not Adjustable
g
mp
7.5 mho Not Adjustable
L 2.7 μH Application Specifi c
f
S
1.3* MHz Not Adjustable
*2.1MHz for LT3467A
From Figure 7, the phase is –138° when the gain reaches
0dB giving a phase margin of 42°. This is more than
adequate. The crossover frequency is 37kHz.
FREQUENCY (Hz)
GAIN (dB)
PHASE (DEG)
50
40
30
20
10
0
–10
–20
–30
–40
–50
0
–45
–90
–135
–180
–225
–270
–315
–360
–405
–450
100 10k 100k 1M
3467 F07
1k
GAIN
PHASE
Figure 7. Bode Plot of 3.3V to 5V Application
TYPICAL APPLICATIONS
Lithium-Ion to 6V Step-Up DC/DC Converter
GND
V
IN
SW
SHDN
FB
V
IN
2.7V TO 4.2V
D1
L1
2.2μH
R1
501k
LT3467
3467 TA02
C2
15μF
C3
1.8pF
C1
2.2μF
R2
133k
V
OUT
6V
275mA AT V
IN
= 2.7V
490mA AT V
IN
= 3.8V
590mA AT V
IN
= 4.2V
C1, C2: X5R OR X7R, 6.3V
D1: ON SEMICONDUCTOR MBRM120
L1: SUMIDA CR43-2R2
SHDN
SS
C4
0.047μF
I
OUT
(mA)
EFFICIENCY (%)
200
95
90
85
80
75
70
65
60
55
50
3467 TA02b
10050 300 400 500 600 700
V
IN
= 3.8V
V
IN
= 4.2V
V
IN
= 2.7V
Li-Ion to 6V