Datasheet

LTC3789
4
3789fa
elecTrical characTerisTics
The l denotes the specifications which apply over the specified operating
junction temperature range, otherwise specifications are at T
A
= 25°C (Note 2). V
IN
= 15V, V
RUN
= 5V, unless otherwise noted.
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
INTV
CC
Linear Regulator
V
INTVCCVIN
Internal V
CC
Voltage 6.5V < V
IN
< 40V, V
EXTVCC
= 0V 5.2 5.5 5.8 V
V
LDOVIN
INTV
CC
Load Regulation I
CC
= 0mA to 20mA, V
EXTVCC
= 0V 0.2 1.0 %
V
INTVCCEXT
Internal V
CC
Voltage 6.5V < V
EXTVCC
< 14V 5.2 5.5 5.8 V
V
LDOEXT
INTV
CC
Load Regulation I
CC
= 0mA to 20mA, V
EXTVCC
= 12V 0.2 1.0 %
V
EXTVCC
EXTV
CC
Switchover Voltage I
CC
= 0mA to 20mA, EXTV
CC
Ramping Positive 4.7 4.8 V
V
LDOHYS
EXTV
CC
Hysteresis 0.25 V
Oscillator and Phase-Locked Loop
f
NOM
Nominal Frequency V
FREQ
= 1.2V, R
FREQ
= 1.22k 350 400 440 kHz
f
LOW
Low Fixed Frequency V
FREQ
= 0V 175 200 225 kHz
f
HIGH
High Fixed Frequency V
FREQ
= 2.4V 570 640 710 kHz
f
SYNC
Synchronizable Frequency MODE/PLLIN = External Clock
l
200 600 kHz
R
MODE/PLLIN
MODE/PLLIN Input Resistance 220 kΩ
I
FREQ
Frequency Setting Current 8 10 12 µA
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 V
FB
with Respect to Set Output Voltage
V
FB
Ramping Negative
V
FB
Ramping Positive
–10
10
%
%
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 LTC3789 is tested under pulse load conditions such
that
T
J
≈ T
A
. The LTC3789E is guaranteed to meet performance specifications
from 0°C to 85°C operating junction temperature. Specifications over
the –40°C to 125°C operating junction temperature range are assured by
design, characterization and correlation with statistical process controls.
The LTC3789I is guaranteed to meet performance specifications over the
full –40°C to 125°C operating junction temperature range.
Note 3: T
J
is calculated from the ambient temperature T
A
and power
dissipation P
D
according to the following formula:
LTC3789GN: T
J
= T
A
+ (P
D
• 80°C/W)
LTC3789UFD: T
J
= T
A
+ (P
D
• 34°C/W)
Note 4: The LTC3789 is tested in a feedback loop that servos V
ITH
to a
specified voltage and measures the resultant V
FB
.
Note 5: Dynamic supply current is higher due to the gate charge being
delivered at the switching frequency. See the Applications Information
section.