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| LTC3876_15 Datasheet, PDF (4/48 Pages) Linear Technology – Dual DC/DC Controller for DDR Power with Differential VDDQ Sensing and 50mA VTT Reference | |||
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LTC3876
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
CONDITIONS
MIN TYP MAX UNITS
Start-Up and Shutdown
VRUN(TH)
VRUN(HYS)
IRUN(OFF)
IRUN(HYS)
VUVLO(INTVCC)
RUN Pin On Threshold
RUN Pin On Hysteresis
RUN Pin Pull-Up Current When Off
RUN Pin Pull-Up Current Hysteresis
INTVCC Undervoltage Lockout
ITRACK/SS
Soft-Start Pull-Up Current
Frequency and Clock Synchronization
VRUN Rising
VRUN Falling from VRUN(TH)
RUN = SGND
IRUN(HYS) = IRUN(ON) â IRUN(OFF)
INTVCC Falling
INTVCC Rising
0V < TRACK/SS < 0.6V
l 1.15 1.2 1.25
V
100
mV
2.5
μA
10
μA
l 3.3 3.7
V
l
4.2 4.5
V
1
μA
fCLKOUT
Clock Output Frequency
(Steady-State Switching Frequency)
ÏVTT
VTT Channel 2 Phase
(Relative to Channel 1)
ÏCLKOUT
CLKOUT Phase
(Relative to Channel 1)
VCLKOUT(H)
VCLKOUT(L)
VPLLIN(H)
VPLLIN(L)
RMODE/PLLIN
Gate Drivers
Clock Output Voltage High
Clock Output Voltage Low
Clock Input Voltage High
Clock Input Voltage Low
MODE/PLLIN Input DC Resistance
RT = 205k
RT = 80.6k
RT = 18.2k
VPHASMD = SGND
VPHASMD = Floating
VPHASMD = INTVCC
VPHASMD = SGND
VPHASMD = Floating
VPHASMD = INTVCC
Pulling to INTVCC
Pulling to SGND
fMODE/PLLIN >100kHz
fMODE/PLLIN >100kHz
200
kHz
450 500 550 kHz
2000
kHz
180
Deg
180
Deg
240
Deg
60
Deg
90
Deg
120
Deg
VINTVCC
V
0
V
2
V
â0.5
V
600
kΩ
RTG(UP)1,2
RTG(DOWN)1,2
RBG(UP)1
RBG(UP)2
RBG(DOWN)1,2
TD(TG/BG)1,2
TD(BG/TG)1,2
VTT Reference
TG Driver Pull-Up On-Resistance
TG High
TG Driver Pull-Down On-Resistance
TG Low
BG Driver 1 Pull-Up On-Resistance
BG1 High
BG Driver 2 Pull-Up On-Resistance
BG2 High
BG Driver Pull-Down On-Resistance
BG Low
Top Gate Off to Bottom Gate On Delay Time (Note 6)
Bottom Gate Off to Top Gate On Delay Time (Note 6)
2.5
Ω
1.2
Ω
2.5
Ω
1.6
Ω
0.8
Ω
20
ns
15
ns
VTTR(IVTTR)
VTTR Load Regulation
(VTTR(IVTTR) is Measured Through an
Internal Kelvin Connection to the VTTR Pin
and is Specified as the Ratio (VTTR(IVTTR)/
VDDQ)
â50mA < IVTTR < 50mA; TA = â40°C to 125°C
1.5 < VDDQ < 2.5
1.0 < VDDQ < 1.5
l 0.4940
l 0.4930
0.5060 V/V
0.5070 V/V
Internal VCC Regulator
VDRVCC1
Internal Regulated DRVCC1 Voltage
âVDRVCC1
DRVCC1 Load Regulation
VEXTVCC(TH)
EXTVCC Switchover Voltage
VEXTVCC(HYS) EXTVCC Switchover Hysteresis
âVDRVCC2
EXTVCC to DRVCC2 Voltage Drop
6V < VIN < 38V
ICC = 0mA to 100mA
EXTVCC Rising
VEXTVCC = 5V, IDRVCC2 = 100mA
5.0 5.3 5.6
V
â1.5 â3
%
4.4 4.6 4.8
V
200
mV
200
mV
3876f
4
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