LTC3865-1_15 Datasheet, PDF (5/38 Pages) Linear Technology – Dual, 2-Phase Synchronous DC/DC Controller with Pin Selectable Outputs

LTC3865/LTC3865-1
ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating
junction temperature range, otherwise specifications are at T_A = 25°C (Note 2). V_IN = 15V, V_RUN1,2 = 5V unless otherwise noted.
SYMBOL PARAMETER
BG R_DOWN
TG1,2 t_r
TG1,2 t_f
BG Driver Pull-Down On-Resistance
TG Transition Time:
Rise Time
Fall Time
BG1,2 t_r
BG1,2 t_f
BG Transition Time:
Rise Time
Fall Time
TG/BG t_1D Top Gate Off to Bottom Gate On Delay
Synchronous Switch-On Delay Time
BG/TG t_2D Bottom Gate Off to Top Gate On Delay
Top Switch-On Delay Time
t_ON(MIN)
Minimum On-Time
INTV_CC Linear Regulator
V_INTVCC
Internal V_CC Voltage
V_LDO INT INTV_CC Load Regulation
V_EXTVCC
EXTV_CC Switchover Voltage
V_LDO EXT EXTV_CC Voltage Drop
V_LDOHYS
EXTV_CC Hysteresis
Oscillator and Phase-Locked Loop
f_NOM
Nominal Frequency
f_LOW
Lowest Frequency
f_HIGH
Highest Frequency
R_MODE/PLLIN MODE/PLLIN Input Resistance
I_FREQ
Frequency Setting Current
PGOOD OUTPUT
V_PGL
I_PGOOD
V_PG
PGOOD Voltage Low
PGOOD Leakage Current
PGOOD Trip Level
t_PG
PGOOD Bad Blanking Time
CONDITIONS
BG Low
(Note 6)
C_LOAD = 3300pF
C_LOAD = 3300pF
(Note 6)
C_LOAD = 3300pF
C_LOAD = 3300pF
C_LOAD = 3300pF Each Driver
C_LOAD = 3300pF Each Driver
(Note 7)
6V < V_IN < 38V
I_CC = 0mA to 20mA
EXTV_CC Ramping Positive
I_CC = 20mA, V_EXTVCC = 5V
R_FREQ = 162k
R_FREQ = 0Ω
R_FREQ ≥ 325k
V_FREQ = 1.22V
I_PGOOD = 2mA
V_PGOOD = 5V
V_OSENSE with Respect to Set Regulated Voltage
VID11 = VID12 = VID21 = VID22 = Float
V_OSENSE Ramping Negative
V_OSENSE Ramping Postitive
Measured from VID Transitition Edge
MIN TYP MAX UNITS
1.4
Ω
25
ns
25
ns
25
ns
25
ns
30
ns
30
ns
90
ns
4.8 5.0 5.2
V
0.5
2
%
l 4.5 4.7
V
50 100
mV
200
mV
450 500 550
kHz
210 250 290
kHz
650 770 880
kHz
250
kΩ
6.5 7.5 8.5
μA
0.1 0.3
V
±2
μA
–7 –10 –12.5
%
7
10 12.5
%
100
μs
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 LTC3865/LTC3865-1 are tested under pulsed load conditions
such that T_J ≈ T_A. The LTC3865E/LTC3865E-1 are guaranteed to meet
performance specifications over the 0°C to 85°C operating junction
temperature range. Specifications over the –40°C to 125°C operating
junction temperature range are assured by design, characterization and
correlation with statistical process controls. The LTC3865I/LTC3865I-1
are guaranteed to meet performance specifications over the full –40°C
to 125°C operating junction temperature range. 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 resistance 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 formulas:
LTC3865UH: T_J = T_A + (P_D • 34°C/W)
LTC3865FE: T_J = T_A + (P_D • 25°C/W)
Note 4: The LTC3865/LTC3865-1 are tested in a feedback loop that servos
V_ITH1,2 to a specified voltage and measures the resultant V_OSENSE1,2.
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).
Note 8: V_SENSE(MAX) defaults to 50mV for the LTC3865-1.
Note 9: Guaranteed by design.
3865fb
5