Datasheet

LTC3890
4
3890fc
ELECTRICAL CHARACTERISTICS
The l denotes the specifications which apply over the specified operating
junction temperature range, otherwise specifications are at T
A
= 25°C. V
IN
= 12V, V
RUN1,2
= 5V, EXTV
CC
= 0V unless otherwise noted.
(Note 2)
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
BG/TG t
1D
Bottom Gate Off to Top Gate On Delay
Top Switch-On Delay Time
C
LOAD
= 3300pF Each Driver 30 ns
t
ON(MIN)
Minimum On-Time (Note 7) 95 ns
INTV
CC
Linear Regulator
V
INTVCCVIN
Internal V
CC
Voltage 6V < V
IN
< 60V, V
EXTVCC
= 0V 4.85 5.1 5.35 V
V
LDOVIN
INTV
CC
Load Regulation I
CC
= 0mA to 50mA, V
EXTVCC
= 0V 0.7 1.1 %
V
INTVCCEXT
Internal V
CC
Voltage 6V < V
EXTVCC
< 13V 4.85 5.1 5.35 V
V
LDOEXT
INTV
CC
Load Regulation I
CC
= 0mA to 50mA, V
EXTVCC
= 8.5V 0.6 1.1 %
V
EXTVCC
EXTV
CC
Switchover Voltage EXTV
CC
Ramping Positive 4.5 4.7 4.9 V
V
LDOHYS
EXTV
CC
Hysteresis 250 mV
Oscillator and Phase-Locked Loop
f
25kΩ
Programmable Frequency R
FREQ
= 25k, PLLIN/MODE = DC Voltage 105 kHz
f
65kΩ
Programmable Frequency R
FREQ
= 65k, PLLIN/MODE = DC Voltage 375 440 505 kHz
f
105kΩ
Programmable Frequency R
FREQ
= 105k, PLLIN/MODE = DC Voltage 835 kHz
f
LOW
Low Fixed Frequency V
FREQ
= 0V, PLLIN/MODE = DC Voltage 320 350 380 kHz
f
HIGH
High Fixed Frequency V
FREQ
= INTV
CC
, PLLIN/MODE = DC Voltage 485 535 585 kHz
f
SYNC
Synchronizable Frequency PLLIN/MODE = External Clock
l
75 850 kHz
PGOOD1 and PGOOD2 Outputs
V
PGL
PGOOD Voltage Low I
PGOOD
= 2mA 0.2 0.4 V
I
PGOOD
PGOOD Leakage Current V
PGOOD
= 5V ±1 µA
V
PG
PGOOD Trip Level V
FB
with Respect to Set Regulated Voltage
V
FB
Ramping Negative
Hysteresis
–13 –10
2.5
–7 %
%
V
FB
with Respect to Set Regulated Voltage
V
FB
Ramping Positive
Hysteresis
7 10
2.5
13 %
%
t
PG
Delay for Reporting a Fault 25 µs
Note 1: Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Ratings for extended periods may affect device reliability and
lifetime.
Note 2: The LTC3890 is tested under pulsed load conditions such that
T
J
≈ T
A
. The LTC3890E 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 LTC3890I is guaranteed
over the –40°C to 125°C operating junction temperature range, the
LTC3890H is guaranteed over the –40°C to 150°C operating junction
temperature range and the LTC3890MP is tested and guaranteed over the
–55°C to 150°C operating junction temperature range.
High junction temperatures degrade operating lifetimes; operating lifetime
is derated for junction temperatures greater than 125°C. Note that the
maximum ambient temperature consistent with these specifications is
determined by specific operating conditions in conjunction with board
layout, the rated package thermal impedance and other environmental
factors.
Note 3: T
J
is calculated from the ambient temperature T
A
and power
dissipation P
D
according to the following formula:
T
J
= T
A
+ (P
D
• 34°C/W)
Note 4: The LTC3890 is tested in a feedback loop that servos V
ITH1,2
to
a specified voltage and measures the resultant V
FB
. The specification at
85°C is not tested in production and is assured by design, characterization
and correlation to production testing at other temperatures (125°C for
the LTC3890E/LTC3890I, 150°C for the LTC3890H/LTC3890MP). For the
LTC3890MP, the specification at –40°C is not tested in production and is
assured by design, characterization and correlation to production testing
at –55°C.
Note 5: Dynamic supply current is higher due to the gate charge being
delivered at the switching frequency. See Applications information.
Note 6: Rise and fall times are measured using 10% and 90% levels. Delay
times are measured using 50% levels.
Note 7: The minimum on-time condition is specified for an inductor
peak-to-peak ripple current ≥ 40% of I
MAX
(See Minimum On-Time
Considerations in the Applications Information section).
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