lt3505ems8e-trpbf Linear Technology Corporation, lt3505ems8e-trpbf Datasheet - Page 15

• Manufacturer Part Number: lt3505ems8e-trpbf
• Description: 1.2a, Step-down Switching Regulator In 3mm X 3mm Dfn
• Manufacturer: Linear Technology Corporation

APPLICATIONS INFORMATION
V
IN
V
MAX V
BOOST
V
BOOST
IN
– V
V
V
V
C
C
C
SW
FB
100k
FB
100k
FB
301k
Figure 5. Transient Load Response of the LT3505 with Different Output Capacitors as the
Load Current is Stepped from 500mA to 1.2A. V
LT3505
BOOST
22pF
22pF
22pF
≅ V
GND
≅ V
IN
32.4k
10.0k
32.4k
10.0k
OUT
+ V
32.4k
10.0k
SW
OUT
(6a)
44pF
66pF
Figure 6. Two Circuits for Generating the Boost Voltage
22pF
C3
+
D2
10µF
×2
10µF
120µF
KEMET
A700D127M006ATE015
V
V
V
OUT
OUT
OUT
3505 F06a
V
OUT
AC COUPLED
AC COUPLED
AC COUPLED
20mV/DIV
20mV/DIV
20mV/DIV
IN
1A/DIV
1A/DIV
1A/DIV
= 12V, V
I
I
I
V
V
V
LOAD
LOAD
LOAD
OUT
OUT
OUT
V
IN
OUT
= 3.3V, L = 2µH, R
V
MAX V
BOOST
V
BOOST
D2
IN
– V
SW
LT3505
BOOST
≅ 2V
GND
10µs/DIV
10µs/DIV
10µs/DIV
≅ V
IN
IN
SW
(6b)
T
= 20.0k
C3
3505 F05b
3505 F05c
3505 F05a
LT3505
3505 F06b
V
OUT
15
3505fc