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LTC3729L-6 Datasheet, PDF (3/28 Pages) Linear Technology – PolyPhase, Synchronous Step-Down Switching Regulator
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LTC3729L-6
ELECTRICAL CHARACTERISTICS The q denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. VIN = 15V, VRUN/SS = 5V unless otherwise noted.
SYMBOL PARAMETER
CONDITIONS
MIN TYP MAX UNITS
VLOADREG Output Voltage Load Regulation
(Note 3)
Measured in Servo Loop; ITH Voltage = 0.7V
q
Measured in Servo Loop; ITH Voltage = 2V
q
0.1
0.5
%
– 0.1 – 0.5
%
VREFLNREG Reference Voltage Line Regulation
VIN = 3.6V to 30V (Note 3)
0.002 0.02
%/V
VOVL
Output Overvoltage Threshold
Measured at VEAIN
q 0.64 0.66 0.68
V
UVLO
Undervoltage Lockout
VIN Ramping Down
3
3.5
4
V
gm
Transconductance Amplifier gm
ITH = 1.2V; Sink/Source 5µA; (Note 3)
3
mmho
gmOL
Transconductance Amplifier Gain
ITH = 1.2V; (gmxZL; No Ext Load); (Note 3)
1.5
V/mV
IQ
Input DC Supply Current
Normal Mode
Shutdown
(Note 4)
EXTVCC Tied to VOUT; VOUT = 5V
VRUN/SS = 0V
470
µA
20
40
µA
IRUN/SS
Soft-Start Charge Current
VRUN/SS = 1.9V
– 0.5 – 1.2
µA
VRUN/SS
RUN/SS Pin ON Threshold
VRUN/SS Rising
1.0
1.5
2.0
V
VRUN/SSLO RUN/SS Pin Latchoff Arming
VRUN/SS Rising from 3V
4.1 4.75
V
ISCL
RUN/SS Discharge Current
Soft Short Condition VEAIN = 0.375V; VRUN/SS = 4.5V
0.5
2
4
µA
ISDLDO
Shutdown Latch Disable Current
VEAIN = 0.4V
1.6
5
µA
ISENSE
Total Sense Pins Source Current
Each Channel; VSENSE1–, 2– = VSENSE1+, 2+ = 0V
– 85 – 60
µA
DFMAX
Maximum Duty Factor
In Dropout; VSENSEMAX ≤ 30mV
98
99.5
%
TG1, 2 tr
TG1, 2 tf
Top Gate Transition Time:
Rise Time
Fall Time
CLOAD = 3300pF
CLOAD = 3300pF
55
100
ns
55
100
ns
BG1, 2 tr
BG1, 2 tf
Bottom Gate Transition Time:
Rise Time
Fall Time
CLOAD = 3300pF
CLOAD = 3300pF
45
100
ns
45
90
ns
TG/BG t1D Top Gate Off to Bottom Gate On Delay
Synchronous Switch-On Delay Time CLOAD = 3300pF Each Driver
80
ns
BG/TG t2D Bottom Gate Off to Top Gate On Delay
Top Switch-On Delay Time
CLOAD = 3300pF Each Driver
80
ns
tON(MIN)
Minimum On-Time
Tested with a Square Wave (Note 5)
100
ns
Internal VCC Regulator
VINTVCC
Internal VCC Voltage
6V < VIN < 30V; VEXTVCC = 4V
4.8
5.0
5.2
V
VLDO INT INTVCC Load Regulation
ICC = 0 to 20mA; VEXTVCC = 4V
0.2
2.0
%
VLDO EXT EXTVCC Voltage Drop
ICC = 20mA; VEXTVCC = 5V
100 200
mV
VEXTVCC
EXTVCC Switchover Voltage
ICC = 20mA, EXTVCC Ramping Positive
q 4.5
4.7
V
VLDOHYS EXTVCC Switchover Hysteresis
ICC = 20mA, EXTVCC Ramping Negative
0.2
V
Oscillator and Phase-Locked Loop
fNOM
fLOW
fHIGH
RPLLIN
IPLLFLTR
Nominal Frequency
Lowest Frequency
Highest Frequency
PLLIN Input Resistance
Phase Detector Output Current
Sinking Capability
Sourcing Capability
VPLLFLTR = 1.2V
VPLLFLTR = 0V
VPLLFLTR ≥ 2.4V
fPLLIN < fOSC
fPLLIN > fOSC
360 400 440
kHz
230 260 290
kHz
480 550 620
kHz
50
kΩ
– 15
µA
15
µA
sn3729l6 3729l6fs
3
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