Datasheet

LTC3568
3
3568fa
f
OSC
Oscillator Frequency R
T
= 324k
(Note 7)
0.85 1 1.15
4
MHz
MHz
f
SYNC
Synchronization Frequency (Note 7) 0.4 4 MHz
I
LIM
Peak Switch Current Limit I
TH
= 1.3 2.4 3 4 A
R
DS(ON)
Top Switch On-Resistance (Note 6) V
IN
= 3.3V 0.11 0.15
Ω
Bottom Switch On-Resistance (Note 6) V
IN
= 3.3V 0.11 0.15
Ω
I
SW(LKG)
Switch Leakage Current V
IN
= 6V, V
ITH/RUN
= 0V, V
FB
= 0V 0.01 1 µA
V
UVLO
Undervoltage Lockout Threshold V
IN
Ramping Down 2 2.25 V
PGOOD Power Good Threshold V
FB
Ramping Up, SHDN/R
T
= 1V
V
FB
Ramping Down, SHDN/R
T
= 1V
6.8
–7.6
%
%
RPGOOD Power Good Pull-Down On-Resistance 118 200
Ω
elecTrical characTerisTics
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
IN
= 3.3V, R
T
= 324k unless otherwise specified. (Note 2)
Note 1: Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
Note
2: The LTC3568 is tested under pulsed load conditions such that T
J
=
T
A
. The LTC3568E is guaranteed to meet performance specifications from
0°C to 85°C. Specifications over the –40°C to 125°C operating junction
temperature range are assured by design, characterization and correlation
with statistical process controls. The LTC3568I is guaranteed over the
full –40°C to 125°C operating junction temperature range. The maximum
ambient temperature is determined by specific operating conditions in
conjunction with board layout, the rated package thermal resistors and
other environmental factors.
Note
3: The LTC3568 is tested in a feedback loop which servos V
FB
to the
midpoint for the error amplifier (V
ITH
= 0.6V).
Note 4: Dynamic supply current is higher due to the internal gate charge
being delivered at the switching frequency.
Note
5: T
J
is calculated from the ambient T
A
and power dissipation P
D
according to the following formula:
T
J
= T
A
+ (P
D
• 43°C/W)
Note 6: Switch on-resistance is guaranteed by correlation to wafer level
measurements.
Note
7: 4MHz operation is guaranteed by design but not production tested
and is subject to duty cycle limitations (see Applications Information).
Note
8: This IC includes overtemperature protection that is intended
to protect the device during momentary overload conditions. Junction
temperature will exceed 125°C when overtemperature protection is active.
Continuous operation above the specified maximum operating junction
temperature may impair device reliability.