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LTC3890 Datasheet, PDF (4/36 Pages) Linear Technology – 60V Low IQ, Dual, 2-Phase Synchronous Step-Down DC/DC Controller | |||
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LTC3890
ELECTRICAL CHARACTERISTICS The l denotes the speciï¬cations which apply over the full operating
junction temperature range, otherwise speciï¬cations are at TJ = 25°C. VIN = 12V, VRUN1,2 = 5V, EXTVCC = 0V unless otherwise noted.
SYMBOL PARAMETER
CONDITIONS
MIN
TYP
MAX UNITS
INTVCC Linear Regulator
VINTVCCVIN
VLDOVIN
VINTVCCEXT
VLDOEXT
VEXTVCC
Internal VCC Voltage
INTVCC Load Regulation
Internal VCC Voltage
INTVCC Load Regulation
EXTVCC Switchover Voltage
6V < VIN < 60V, VEXTVCC = 0V
ICC = 0mA to 50mA, VEXTVCC = 0V
6V < VEXTVCC < 13V
ICC = 0mA to 50mA, VEXTVCC = 8.5V
EXTVCC Ramping Positive
4.85
5.1
5.35
V
0.7
1.1
%
4.85
5.1
5.35
V
0.6
1.1
%
4.5
4.7
4.9
V
VLDOHYS
EXTVCC Hysteresis
Oscillator and Phase-Locked Loop
250
mV
f25kΩ
f65kΩ
f105kΩ
fLOW
Programmable Frequency
Programmable Frequency
Programmable Frequency
Low Fixed Frequency
RFREQ = 25k, PLLIN/MODE = DC Voltage
RFREQ = 65k, PLLIN/MODE = DC Voltage
RFREQ = 105k, PLLIN/MODE = DC Voltage
VFREQ = 0V, PLLIN/MODE = DC Voltage
105
kHz
375
440
505
kHz
835
kHz
320
350
380
kHz
fHIGH
High Fixed Frequency
fSYNC
Synchronizable Frequency
PGOOD1 and PGOOD2 Outputs
VFREQ = INTVCC, PLLIN/MODE = DC Voltage
PLLIN/MODE = External Clock
485
535
585
kHz
l 75
850
kHz
VPGL
IPGOOD
VPG
PGOOD Voltage Low
PGOOD Leakage Current
PGOOD Trip Level
IPGOOD = 2mA
VPGOOD = 5V
VFB with Respect to Set Regulated Voltage
VFB Ramping Negative
Hysteresis
0.2
0.4
V
±1
μA
â13
â10
â7
%
2.5
%
VFB with Respect to Set Regulated Voltage
VFB Ramping Positive
Hysteresis
7
10
13
%
2.5
%
tPG
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 LTC3890E is guaranteed to meet performance speciï¬cations
from 0°C to 125°C. Speciï¬cations over the â40°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 full â40°C to 125°C operating junction temperature range.
Note 3: TJ is calculated from the ambient temperature TA and power
dissipation PD according to the following formula:
TJ = TA + (PD ⢠34°C/W)
Note 4: The LTC3890 is tested in a feedback loop that servos VITH1,2 to a
speciï¬ed voltage and measures the resultant VFB1,2. The speciï¬cation at
85°C is not tested in production. This speciï¬cation is assured by design,
characterization and correlation to production testing at 125°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 speciï¬ed for an inductor
peak-to-peak ripple current ⥠40% of IMAX (See Minimum On-Time
Considerations in the Applications Information section).
3890f
4
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