LTC3867_15 Datasheet, PDF (5/36 Pages) Linear Technology – Low IQ, Dual 2-Phase Synchronous Step-Down Controller

LTC3867
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.
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
TG t_r
TG t_f
BG t_r
BG t_f
TG/BG t_1D
TG Transition Time
Rise Time
Fall Time
BG Transition Time
Rise Time
Fall Time
Top Gate Off to Bottom Gate On Delay,
Synchronous Switch-On Delay Time
C_LOAD = 3300pF
C_LOAD = 3300pF (Note 5)
C_LOAD = 3300pF
C_LOAD = 3300pF (Note 5)
C_LOAD = 3300pF Each Driver
25
ns
25
ns
25
ns
25
ns
30
ns
BG/TG t_2D
Bottom Gate Off to Top Gate On Delay, C_LOAD = 3300pF Each Driver
Top Switch-On Delay Time
30
ns
Thermal Shutdown
I_ITSD
V_ITSD
Source Current
Comparator Trip Point
I_ITSD = 500mV
20
µA
950
mV
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)
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.
3867f
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