LTC3867
5
3867f
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 specified.
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 LTC3867 is tested under pulsed load conditions such that
T
J
≈ T
A
. The LTC3867E 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 LTC3867I is guaranteed to meet performance specifications over the
full –40°C to 125°C operating junction temperature range. The maximum
ambient temperature consistent with these specifications is determined
by specific operating conditions in conjunction with board layout, the
package thermal impedance and other environmental factors.
T
J
is calculated from the ambient temperature, T
A
, and power dissipation,
P
D
, according to the following formula:
LTC3867UF: T
J
= T
A
+ (P
D
• 47°C/W)
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
TG t
r
TG t
f
TG Transition Time
Rise Time
Fall Time
C
LOAD
= 3300pF
C
LOAD
= 3300pF (Note 5)
25
25
ns
ns
BG t
r
BG t
f
BG Transition Time
Rise Time
Fall Time
C
LOAD
= 3300pF
C
LOAD
= 3300pF (Note 5)
25
25
ns
ns
TG/BG t
1D
Top Gate Off to Bottom Gate On Delay,
Synchronous Switch-On Delay Time
C
LOAD
= 3300pF Each Driver 30 ns
BG/TG t
2D
Bottom Gate Off to Top Gate On Delay,
Top Switch-On Delay Time
C
LOAD
= 3300pF Each Driver 30 ns
Thermal Shutdown
I
ITSD
Source Current I
ITSD
= 500mV 20 µA
V
ITSD
Comparator Trip Point 950 mV
Note 3: The LTC3867 is tested in a feedback loop that servos V
ITH
to a
specified voltage and measures the resultant V
FB
.
Note 4: Dynamic supply current is higher due to the gate charge being
delivered at the switching frequency. See Applications Information.
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 condition corresponds to the on inductor
peak-to-peak ripple current ≥40% of I
MAX
(see Minimum On-Time
Considerations in the Applications Information section).
Note 7: Guaranteed by design.
