LTC3416 Linear Technology, LTC3416 Datasheet - Page 6

• Manufacturer Part Number: LTC3416
• Description: 4A/ 4MHz/ Monolithic Synchronous Step-Down Regulator
• Manufacturer: Linear Technology

OPERATIO
Main Control Loop
The LTC3416 is a monolithic, constant frequency, current
mode step-down DC/DC converter. During normal opera-
tion, the internal top power switch (P-channel MOSFET) is
turned on at the beginning of each clock cycle. Current in
the inductor increases until the current comparator trips
and turns off the top power MOSFET. The peak inductor
current at which the current comparator shuts off the top
power switch is controlled by the voltage on the I
The error amplifier adjusts the voltage on the I
comparing the feedback signal from a resistor divider on
the V
current increases, it causes a reduction in the feedback
voltage relative to the reference. The error amplifier raises
LTC3416
FU CTIO AL DIAGRA
6
U
FB
pin with an internal 0.8V reference. When the load
RUN/SS
PGOOD
TRACK
V
19
17
3
4
FB
U
RUN
U
0.74V
0.86V
–
–
–
+
+
+
SV
REFERENCE
16
VOLTAGE
IN
AMPLIFIER
ERROR
SGND
5
W
EXPOSED
PAD
21
OSCILLATOR
I
18
TH
TH
R
2
T
TH
pin by
COMPENSATION
pin.
RECOVERY
SLOPE
LOGIC
the I
the new load current. When the top power MOSFET shuts
off, the synchronous power switch (N-channel MOSFET)
turns on until either the bottom current limit is reached or
the beginning of the next clock cycle. The bottom current
limit is set at –5A.
The operating frequency is externally set by an external
resistor connected between the R
practical switching frequency can range from 300kHz to
4MHz.
Overvoltage and undervoltage comparators will pull the
PGOOD output low if the output voltage comes out of
regulation by 7.5%. In an overvoltage condition, the top
TH
COMPENSATION
NMOS CURRENT
voltage until the average inductor current matches
COMPARATOR
SLOPE
PMOS CURRENT
COMPARATOR
+
–
+
–
www.DataSheet4U.com
7
T
PV
pin and ground. The
IN
14
3416 FD
12
13
10
11
20
8
9
1
SW
PGND
3416f