LTC3728L/LTC3728LX
5
3728lxff
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: T
J
is calculated from the ambient temperature T
A
and power
dissipation P
D
according to the following formulas:
LTC3728LUH/LTC3728LXUH: T
J
= T
A
+ (P
D
• 34°C/W)
LTC3728LGN: T
J
= T
A
+ (P
D
• 95°C/W)
Note 3: The IC is tested in a feedback loop that servos V
ITH1, 2
to a
specified voltage and measures the resultant V
OSENSE1, 2.
Note 4: Dynamic supply current is higher due to the gate charge being
delivered at the switching frequency. See the Applications Information
section.
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
INTV
CC
Linear Regulator
V
INTVCC
Internal V
CC
Voltage 6V < V
IN
< 30V, V
EXTVCC
= 4V 4.8 5.0 5.2 V
V
LDO
INT INTV
CC
Load Regulation I
CC
= 0 to 20mA, V
EXTVCC
= 4V 0.2 2.0 %
V
LDO
EXT EXTV
CC
Voltage Drop I
CC
= 20mA, V
EXTVCC
= 5V 100 200 mV
V
EXTVCC
EXTV
CC
Switchover Voltage I
CC
= 20mA, EXTV
CC
Ramping Positive
●
4.5 4.7 V
V
LDOHYS
EXTV
CC
Hysteresis 0.2 V
Oscillator and Phase-Locked Loop
f
NOM
Nominal Frequency V
PLLFLTR
= 1.2V 360 400 440 kHz
f
LOW
Lowest Frequency V
PLLFLTR
= 0V 230 260 290 kHz
f
HIGH
Highest Frequency V
PLLFLTR
≥ 2.4V 480 550 590 kHz
R
PLLIN
PLLIN Input Resistance 50 kΩ
I
PLLFLTR
Phase Detector Output Current
Sinking Capability
Sourcing Capability
f
PLLIN
< f
OSC
f
PLLIN
> f
OSC
–15
15
µA
µA
3.3V Linear Regulator
V
3.3OUT
3.3V Regulator Output Voltage No Load
●
3.2 3.35 3.45 V
V
3.3IL
3.3V Regulator Load Regulation I
3.3
= 0 to 10mA 0.5 2 %
V
3.3VL
3.3V Regulator Line Regulation 6V < V
IN
< 30V 0.05 0.2 %
PGOOD Output
V
PGL
PGOOD Voltage Low I
PGOOD
= 2mA 0.1 0.3 V
I
PGOOD
PGOOD Leakage Current V
PGOOD
= 5V ±1 µA
V
PG
PGOOD Trip Level, Either Controller V
OSENSE
with Respect to Set Output Voltage
V
OSENSE
Ramping Negative
V
OSENSE
Ramping Positive
–6
6
–7.5
7.5
–9.5
9.5
%
%
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
= 15V, V
RUN/SS1, 2
= 5V unless otherwise noted.
Note 5: Rise and fall times are measured using 10% and 90% levels. Delay
times are measured using 50% levels.
Note 6: The minimum on-time is tested under an ideal condition without
external power FETs. It can be larger when the IC is operating in an
actual circuit. See Minimum On-Time Considerations in the Applications
Information section.
Note 7: The LTC3728LC/LTC3728LXC are guaranteed to meet performance
specifications from 0°C to 85°C. The LTC3728LE is guaranteed to meet
performance specifications over the –40°C to 85°C operating temperature
range as assured by design, characterization and correlation with statistical
process controls. The LTC3728LI is guaranteed to meet performance
specifications over the –40°C to 85°C operating temperature range.
Note 8: Guaranteed by design.
