Datasheet

LTC3418
5
3418fb
TYPICAL PERFORMANCE CHARACTERISTICS
Load Regulation
Peak Inductor Current
vs Burst Clamp Voltage
V
BCLAMP
(V)
0
0
PEAK INDUCTOR CURRENT (A)
2
4
6
8
0.2 0.4
0.6
0.8
3418 G13
10
12
0.1 0.3
0.5
0.7
3.3V
5V
LOAD CURRENT (A)
0
–0.30
ΔV
OUT
/V
OUT
(%)
–0.25
–0.20
–0.15
–0.10
24
6
8
3418 G14
–0.05
0
13
5
7
V
IN
= 3.3V
V
OUT
= 1.8V
f = 1MHz
Load Step Transient
OUTPUT
VOLTAGE
100mV/DIV
INDUCTOR
CURRENT
5A/DIV
20μs/DIVV
IN
= 3.3V
V
OUT
= 2.5V
LOAD STEP: 800mA TO 8A
3418 G15
Load Step Transient
OUTPUT
VOLTAGE
100mV/DIV
INDUCTOR
CURRENT
5A/DIV
40μs/DIVV
IN
= 3.3V
V
OUT
= 2.5V
LOAD STEP: 3A TO 8A
3418 G16
Burst Mode Operation Start-Up Transient
OUTPUT
VOLTAGE
100mV/DIV
INDUCTOR
CURRENT
1A/DIV
20μs/DIVV
IN
= 3.3V
V
OUT
= 2.5V
LOAD: 200mA
3418 G17
OUTPUT
VOLTAGE
500mV/DIV
INDUCTOR
CURRENT
2A/DIV
1ms/DIVV
IN
= 3.3V
V
OUT
= 2.5V
LOAD: 8A
3418 G18
T
A
= 25°C unless otherwise noted.
PIN FUNCTIONS
SW (Pins 1, 2, 11, 12, 20, 21, 30, 31): Switch Node
Connection to Inductor. This pin connects to the drains
of the internal main and synchronous power MOSFET
switches.
PV
IN
(Pins 3, 4, 9, 10, 22, 23, 28, 29): Power Input
Supply. Decouple these pins to PGND with capacitors on
all four corners of the package.
PGOOD (Pin 5): Power Good Output. Open-drain logic
output that is pulled to ground when the output voltage
is not within ±7.5% of regulation point.
R
T
(Pin 6): Oscillator Resistor Input. Connecting a resistor
to ground from this pin sets the switching frequency.
RUN/SS (Pin 7): Run Control and Soft-Start Input. Forcing
this pin below 0.5V shuts down the LTC3418. In shutdown
all functions are disabled drawing <1.5μA of supply cur-
rent. A capacitor to ground from this pin sets the ramp
time to full output current.
SGND (Pin 8): Signal Ground. All small-signal components
and compensation components should connect to this
ground, which in turn connects to PGND at one point.
PGND (Pins 13, 14, 15, 17, 18, 19, 32, 33, 34, 36, 37,
38): Power Ground. Connect this pin closely to the (–)
terminal of C
IN
and C
OUT
.