Datasheet

LTC3876
4
3876f
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
Start-Up and Shutdown
V
RUN(TH)
RUN Pin On Threshold V
RUN
Rising
l
1.15 1.2 1.25 V
V
RUN(HYS)
RUN Pin On Hysteresis V
RUN
Falling from V
RUN(TH)
100 mV
I
RUN(OFF)
RUN Pin Pull-Up Current When Off RUN = SGND 2.5 µA
I
RUN(HYS)
RUN Pin Pull-Up Current Hysteresis I
RUN(HYS)
= I
RUN(ON)
– I
RUN(OFF)
10 µA
V
UVLO(INTVCC)
INTV
CC
Undervoltage Lockout INTV
CC
Falling
INTV
CC
Rising
l
l
3.3 3.7
4.2 4.5
V
V
I
TRACK/SS
Soft-Start Pull-Up Current 0V < TRACK/SS < 0.6V 1 µA
Frequency and Clock Synchronization
f
CLKOUT
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
φ
VTT
VTT Channel 2 Phase
(Relative to Channel 1)
V
PHASMD
= SGND
V
PHASMD
= Floating
V
PHASMD
= INTV
CC
180
180
240
Deg
Deg
Deg
φ
CLKOUT
CLKOUT Phase
(Relative to Channel 1)
V
PHASMD
= SGND
V
PHASMD
= Floating
V
PHASMD
= INTV
CC
60
90
120
Deg
Deg
Deg
V
CLKOUT(H)
Clock Output Voltage High Pulling to INTV
CC
V
INTVCC
V
V
CLKOUT(L)
Clock Output Voltage Low Pulling to SGND 0 V
V
PLLIN(H)
Clock Input Voltage High f
MODE/PLLIN
>100kHz 2 V
V
PLLIN(L)
Clock Input Voltage Low f
MODE/PLLIN
>100kHz –0.5 V
R
MODE/PLLIN
MODE/PLLIN Input DC Resistance 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
BG Driver 1 Pull-Up On-Resistance BG1 High 2.5 
R
BG(UP)2
BG Driver 2 Pull-Up On-Resistance BG2 High 1.6 
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
VTT Reference
VTTR(I
VTTR
) VTTR Load Regulation
(VTTR(I
VTTR
) is Measured Through an
Internal Kelvin Connection to the VTTR Pin
and is Specified as the Ratio (VTTR(I
VTTR
)/
VDDQ)
–50mA < I
VTTR
< 50mA; T
A
= –40°C to 125°C
1.5 < VDDQ < 2.5
1.0 < VDDQ < 1.5
l
l
0.4940
0.4930
0.5060
0.5070
V/V
V/V
Internal V
CC
Regulator
V
DRVCC1
Internal Regulated DRV
CC1
Voltage 6V < V
IN
< 38V 5.0 5.3 5.6 V
∆V
DRVCC1
DRV
CC1
Load Regulation I
CC
= 0mA to 100mA –1.5 –3 %
V
EXTVCC(TH)
EXTV
CC
Switchover Voltage EXTV
CC
Rising 4.4 4.6 4.8 V
V
EXTVCC(HYS)
EXTV
CC
Switchover Hysteresis 200 mV
∆V
DRVCC2
EXTV
CC
to DRV
CC2
Voltage Drop V
EXTVCC
= 5V, I
DRVCC2
= 100mA 200 mV
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)