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LTC3838-1_15 Datasheet, PDF (4/52 Pages) Linear Technology – Dual, Fast, Accurate Step-Down DC/DC Controller with Dual Differential Output Sensing
LTC3838-1
ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the specified operating
junction temperature range, otherwise specifications are at TA = 25°C. VIN = 15V unless otherwise noted (Note 3).
SYMBOL
PARAMETER
Start-Up and Shutdown
VRUN1,2
RUN Pin On Threshold
RUN Pin On Hysteresis
IRUN1,2
RUN Pin Pull-Up Current When Off
RUN Pin Pull-Up Current Hysteresis
UVLO
INTVCC Undervoltage Lockout
ITRACK/SS1,2 Soft-Start Pull-Up Current
Frequency and Clock Synchronization
f
Clock Output Frequency
(Steady-State Switching Frequency)
Channel 2 Phase (Relative to Channel 1)
CLKOUT Phase (Relative to Channel 1)
VPLLIN(H)
VPLLIN(L)
RMODE/PLLIN
Gate Drivers
Clock Input High Level Into MODE/PLLIN
Clock Input Low Level Into MODE/PLLIN
MODE/PLLIN Input DC Resistance
RTG(UP)1,2
TG Driver Pull-Up On Resistance
RTG(DOWN)1,2 TG Driver Pull-Down On Resistance
RBG(UP)1,2
BG Driver Pull-Up On Resistance
RBG(DOWN)1,2 BG Driver Pull-Down On Resistance
tD(TG/BG)1,2 Top Gate Off to Bottom Gate On Delay Time
tD(BG/TG)1,2 Bottom Gate Off to Top Gate On Delay Time
Internal VCC Regulator
VDRVCC1
Internally Regulated DRVCC1 Voltage
DRVCC1 Load Regulation
VEXTVCC
EXTVCC Switchover Voltage
EXTVCC Switchover Hysteresis
EXTVCC to DRVCC2 Voltage Drop
PGood Output
OV
PGOOD Overvoltage Threshold
UV
PGOOD Undervoltage Threshold
PGOOD Threshold Hysteresis
VPGOOD(L)1,2
tD(PGOOD)1,2
PGOOD Low Voltage
Delay from VFB Fault (OV/UV) to PGOOD Falling
Delay from VFB Good (OV/UV Cleared) to PGOOD
Rising
CONDITIONS
VRUN1,2 Rising
VRUN1,2 Falling from On Threshold
RUN1,2 = SGND
IRUN1,2(HYS) = IRUN1,2(ON) – IRUN1,2(OFF)
INTVCC Falling
INTVCC Rising
0V < TRACK/SS1,2 < 0.6V
RT = 205k
RT = 80.6k
RT = 18.2k
PHASMD = SGND
PHASMD = Floating
PHASMD = INTVCC
PHASMD = SGND
PHASMD = Floating
PHASMD = INTVCC
With Respect to SGND
TG High
TG Low
BG High
BG Low
(Note 6)
(Note 6)
6V < VIN < 38V
IDRVCC1 = 0mA to –100mA
EXTVCC Rising
VEXTVCC = 5V, IDRVCC2 = –100mA
VFB1,2 Rising from Regulated Voltage
VFB1,2 Falling from Regulated Voltage
VFB1,2 Returning to Regulated Voltage
IPGOOD = 2mA
MIN TYP MAX UNITS
l 1.1 1.2 1.3
V
100
mV
1.2
µA
5
µA
l 3.3 3.7
V
l
4.2 4.5
V
1
µA
200
kHz
450 500 550
kHz
2000
kHz
180
Deg
180
Deg
240
Deg
60
Deg
90
Deg
120
Deg
2
V
0.5
V
600
kΩ
2.5
Ω
1.2
Ω
2.5
Ω
0.8
Ω
20
ns
15
ns
5.0 5.3 5.6
V
–1.5 –3
%
4.4 4.6 4.8
V
200
mV
200
mV
5 7.5 10
%
–5 –7.5 –10
%
2.5
%
0.1 0.3
V
50
µs
20
µs
38381f
4
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