Datasheet

LTC3838
4
3838fa
ELECTRICAL CHARACTERISTICS
The l denotes the specifications which apply over the specified operating
junction temperature range, otherwise specifications are at T
A
= 25°C. V
IN
= 15V unless otherwise noted (Note 3).
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
Current Sensing
V
SENSE(MAX)1,2
Maximum Valley Current Sense Threshold
(V
SENSE1,2
+
– V
SENSE1,2
–
)
V
RNG
= 2V, V
FB
= 0.57V, V
SENSE
–
= 2.5V
V
RNG
= 0V, V
FB
= 0.57V, V
SENSE
–
= 2.5V
V
RNG
= INTV
CC
, V
FB
= 0.57V, V
SENSE
–
= 2.5V
l
l
l
80
21
39
100
30
50
120
40
61
mV
mV
mV
V
SENSE(MIN)1,2
Minimum Valley Current Sense Threshold
(V
SENSE1,2
+
– V
SENSE1,2
–
)
(Forced Continuous Mode)
V
RNG
= 2V, V
FB
= 0.63V, V
SENSE
–
= 2.5V
V
RNG
= 0V, V
FB
= 0.63V, V
SENSE
–
= 2.5V
V
RNG
= INTV
CC
, V
FB
= 0.63V, V
SENSE
–
= 2.5V
–50
–15
–25
mV
mV
mV
I
SENSE1,2
+
SENSE1,2
+
Pins Input Bias Current V
SENSE
+
= 0.6V
V
SENSE
+
= 5V
±5
1
±50
±2
nA
µA
I
SENSE1,2
–
SENSE1,2
–
Pins Input Bias Current
(Internal 500k Resistor to SGND)
V
SENSE
–
= 0.6V
V
SENSE
–
= 5V
1.2
10
µA
µA
Start-Up and Shutdown
V
RUN1,2
RUN Pin On Threshold V
RUN1,2
Rising
l
1.1 1.2 1.3 V
RUN Pin On Hysteresis V
RUN1,2
Falling from On Threshold 100 mV
I
RUN1,2
RUN Pin Pull-Up Current when Off RUN1,2 = SGND 1.2 µA
RUN Pin Pull-Up Current Hysteresis I
RUN1,2(HYS)
= I
RUN1,2(ON)
– I
RUN1,2(OFF)
5µA
UVLO INTV
CC
Undervoltage Lockout INTV
CC
Falling
INTV
CC
Rising
l
l
3.3 3.7
4.2 4.5
V
V
I
TRACK/SS1,2
Soft-Start Pull-Up Current 0V < TRACK/SS1,2 < 0.6V 1 µA
Frequency and Clock Synchronization
Clock Output Frequency
(Steady-State Switching Frequency)
R
T
= 205k
R
T
= 80.6k
R
T
= 18.2k
450
200
500
2000
550
kHz
kHz
kHz
Channel 2 Phase (Relative to Channel 1) PHASMD = SGND
PHASMD = Floating
PHASMD = INTV
CC
180
180
240
Deg
Deg
Deg
CLKOUT Phase (Relative to Channel 1) PHASMD = SGND
PHASMD = Floating
PHASMD = INTV
CC
60
90
120
Deg
Deg
Deg
V
PLLIN(H)
Clock Input High Level Into MODE/PLLIN 2 V
V
PLLIN(L)
Clock Input Low Level Into MODE/PLLIN 0.5 V
R
MODE/PLLIN
MODE/PLLIN Input DC Resistance With Respect to SGND 600 k
Gate Drivers
R
TG(UP)1,2
TG Driver Pull-Up On Resistance TG High 2.5 
R
TG(DOWN)1,2
TG Driver Pull-Down On Resistance TG Low 1.2 
R
BG(UP)1,2
BG Driver Pull-Up On Resistance BG High 2.5 
R
BG(DOWN)1,2
BG Driver Pull-Down On Resistance BG Low 0.8 
t
D(TG/BG)1,2
Top Gate Off to Bottom Gate On Delay Time (Note 6) 20 ns
t
D(BG/TG)1,2
Bottom Gate Off to Top Gate On Delay Time (Note 6) 15 ns