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LTC3618 Datasheet, PDF (4/24 Pages) Linear Integrated Systems – Dual 4MHz, 3A Synchronous Buck Converter for DDR Termination | |||
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LTC3618
ELECTRICAL CHARACTERISTICS The l denotes the speciï¬cations which apply over the full operating
junction temperature range, otherwise speciï¬cations are at TA = 25°C (Note 2), SVIN = PVINx = 3.3V, RT = 178k, unless otherwise
speciï¬ed.
SYMBOL
VMODE
(Note 8)
PGOOD1
PGOOD2
tPGOOD
RPGOOD
VRUN
PARAMETER
CONDITIONS
VMODE High Voltage
VMODE Low Voltage
Power Good Voltage Window of
VDDQ
Power Good Voltage Window of VTT
Power Good Blanking Time
Pulse-Skipping Mode
Forced Continuous Mode
TRACK/SS1 = SVIN, Entering Window
VFB1 Ramping Up
VFB1 Ramping Down
TRACK/SS1 = SVIN, Leaving Window
VFB1 Ramping Up
VFB1 Ramping Down
Entering Window
VTT Ramping Up
VTT Ramping Down
Leaving Window
VFB2 Ramping Up
VFB2 Ramping Down
Entering/Leaving Window
Power Good Pull-Down On-Resistance I = 10mA
VRUN Voltage
Input High
Input Low
Pull-Down Resistance
MIN
TYP
1.0
â5
2
5
8
â10.5
â8
â5
2.5
5
8
â10.5
â8
65
105
8
12
l
1
l
4
MAX UNITS
V
0.4
V
â2
%
%
10.5
%
%
â2.5
%
%
10.5
%
%
140
μs
30
Ω
V
0.4
V
MΩ
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 LTC3618 is tested under pulsed load conditions such that
TJ â TA. The LTC3618E is guaranteed to meet performance speciï¬cations
over the 0°C to 85°C operating junction temperature range. 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 LTC3618I is guaranteed to meet speciï¬cations over the
full â40°C to 125°C operating junction temperature range. Note that the
maximum ambient temperature consistent with these speciï¬cations is
determined by speciï¬c operating conditions in conjunction with board
layout, the rated package thermal resistance and other environmental
factors. The junction temperature (TJ, in °C) is calculated from the ambient
temperature (TA, in °C) and power dissipation (PD, in watts) according to
the formula:
TJ = TA + (PD ⢠θJA)
where θJA (in °C/W) is the package thermal impedance.
Note 3: This parameter is tested in a feedback loop which servos VFB1 to
the midpoint for the error ampliï¬er (VITH1 = 0.75V).
Note 4: External compensation on ITH pin.
Note 5: Dynamic supply current is higher due to the internal gate charge
being delivered at the switching frequency.
Note 6: See description of the TRACK/SS pin in the Pin Functions section.
Note 7: When sourcing current, the average output current is deï¬ned
as ï¬owing out of the SW pin. When sinking current, the average output
current is deï¬ned as ï¬owing into the SW pin. Sinking mode requires the
use of forced continuous mode.
Note 8: See description of the MODE pin in the Pin Functions section.
Note 9: Guaranteed by design and correlation to wafer level measurements
for QFN packages.
Note 10: This IC includes overtemperature protection that is intended
to protect the device during momentary overload conditions. Junction
temperature will exceed 125°C when overtemperature protection is active.
Continuous operation above the speciï¬ed maximum operating junction
temperature may impair device reliability or permanently damage the
device.
3618fb
4
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