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LTC3720_15 Datasheet, PDF (3/24 Pages) Linear Technology – Single Phase VRM8.5 Current Mode Step-Down Controller | |||
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LTC3720
ELECTRICAL CHARACTERISTICS The q denotes specifications which apply over the full operating
temperature range, otherwise specifications are TA = 25°C. VIN = 15V unless otherwise noted.
SYMBOL
PARAMETER
CONDITIONS
MIN TYP MAX
VRUN/SS(LE)
VRUN/SS(LT)
IRUN/SS(C)
IRUN/SS(D)
VIN (UVLO)
RUN Pin Latchoff Enable Threshold
RUN Pin Latchoff Threshold
Soft-Start Charge Current
Soft-Start Discharge Current
Undervoltage Lockout
TG RUP
TG Driver Pull-Up On Resistance
TG RDOWN
TG Driver Pull-Down On Resistance
BG RUP
BG Driver Pull-Up On Resistance
BG RDOWN
BG Driver Pull-Down On Resistance
TG tr
TG Rise Time
TG tf
TG Fall Time
BG tr
BG Rise Time
BG tf
BG Fall Time
Internal VCC Regulator
VINTVCC
Internal VCC Voltage
âVLDO(LOADREG) Internal VCC Load Regulation
VEXTVCC
EXTVCC Switchover Voltage
âVEXTVCC
EXTVCC Switch Drop Voltage
âVEXTVCC(HYS) EXTVCC Switchover Hysteresis
PGOOD Output
RUN/SS Pin Rising
RUN/SS Pin Falling
VIN Falling
VIN Rising
TG High
TG Low
BG High
BG Low
CLOAD = 3300pF
CLOAD = 3300pF
CLOAD = 3300pF
CLOAD = 3300pF
6V < VIN < 30V, VEXTVCC = 4V
ICC = 0mA to 20mA, VEXTVCC = 4V
ICC = 20mA, VEXTVCC Rising
ICC = 20mA, VEXTVCC = 5V
4
4.5
3.5
â 0.5 â 1.2
â3
0.8
1.8
3
q
3.4
3.9
q
3.5
4.0
2
3
2
3
3
4
1
2
20
20
20
20
q 4.7
5
5.3
â 0.1
±2
q 4.5
4.7
150 300
200
âVFBH
âVFBL
âVFB(HYS)
VPGL
VID DAC
PGOOD Upper Threshold
PGOOD Lower Threshold
PGOOD Hysteresis
PGOOD Low Voltage
VFB Rising
VFB Falling
VFB Returning
IPGOOD = 5mA
5.5
7.5
9.5
â 5.5 â 7.5 â 9.5
1
2
0.15
0.4
VCC
VVID(T)
VVID(LEAK)
âVOSENSE
RPULLUP
RVID
IVCC
Operating Supply Voltage Range
VID0-VID4 Logic Threshold Voltage
VID0-VID4 Leakage Current
DAC Output Accuracy
Pull-Up Resistance on VID
Resistance from VOSENSE to VFB
Supply Current
VCC = 3.3V
VVID0-VVID4 = VCC
VOSENSE Programmed from
1.05V to 1.825V (Note 5), VCC = 5V
VDIODE = 0.6V (Note 6)
(Note 7)
3.1
5.5
0.4
1.2
2
0.01
±1
â 0.25
0
0.25
28
40
56
6
10
14
1
10
UNITS
V
V
µA
µA
V
V
â¦
â¦
â¦
â¦
ns
ns
ns
ns
V
%
V
mV
mV
%
%
%
V
V
V
µA
%
kâ¦
kâ¦
µA
Note 1: Absolute Maximum Ratings are those values beyond which the life of
a device may be impaired.
Note 2: The LTC3720E is guaranteed to meet performance specifications from
0°C to 70°C. Specifications over the â40°C to 85°C operating temperature
range are assured by design, characterization and correlation with statistical
process controls.
Note 3: TJ is calculated from the ambient temperature TA and power
dissipation PD as follows:
LTC3720EGN: TJ = TA + (PD ⢠95°C/W)
Note 4: The LTC3720 is tested in a feedback loop that adjusts VFB to achieve
a specified error amplifier output voltage (ITH).
Note 5: The LTC3720 VID DAC is tested in a feedback loop that adjusts
VOSENSE to achieve a specified feedback voltage (VFB = 0.8V) for each DAC VID
code.
Note 6: Each built-in pull-up resistor attached to VID inputs also has a series
diode connected to VCC to allow input voltages higher than the VCC supply
without damage or clamping. (See Operation section for further details.)
Note 7: Supply current is specified with all VID inputs floating. Due to the
internal pull-ups on the VID pins, the supply current will increase depending
on the number of grounded VID lines. Each grounded VID line will draw
approximately (VCC â 0.6V)/40k mA. (See Operation section for further
details.)
3720f
3
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