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LTC3855_15 Datasheet, PDF (4/44 Pages) Linear Technology – Dual, Multiphase Synchronous DC/DC Controller with Differential Remote Sense
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LTC3855
Electrical Characteristics The l denotes the specifications which apply over the full operating
junction temperature range (E-Grade), otherwise specifications are at TA = 25°C. VIN = 15V, VRUN1,2 = 5V unless otherwise noted.
SYMBOL PARAMETER
CONDITIONS
MIN
TYP MAX UNITS
TG/BG t1D Top Gate Off to Bottom Gate On Delay CLOAD = 3300pF Each Driver
Synchronous Switch-On Delay Time
30
ns
BG/TG t2D Bottom Gate Off to Top Gate On Delay CLOAD = 3300pF Each Driver
Top Switch-On Delay Time
30
ns
tON(MIN)
Minimum On-Time
INTVCC Linear Regulator
VINTVCC
Internal VCC Voltage
VLDO INT INTVCC Load Regulation
VEXTVCC
EXTVCC Switchover Voltage
VLDO EXT EXTVCC Voltage Drop
VLDOHYS EXTVCC Hysteresis
Oscillator and Phase-Locked Loop
(Note 7)
6V < VIN < 38V
ICC = 0mA to 20mA
EXTVCC Ramping Positive
ICC = 20mA, VEXTVCC = 5V
4.8
l 4.5
90
ns
5
5.2
V
0.5
2
%
4.7
V
50
100 mV
200
mV
fNOM
Nominal Frequency
fLOW
Lowest Frequency
fHIGH
Highest Frequency
RMODE/PLLIN MODE/PLLIN Input Resistance
IFREQ
Frequency Setting Current
CLKOUT Phase (Relative to Controller 1)
CLKHIGH Clock High Output Voltage
CLKLOW Clock Low Output Voltage
PGOOD Output
VFREQ = 1.2V
VFREQ = 0V
VFREQ ≥ 2.4V
PHASMD = GND
PHASMD = Float
PHASMD = INTVCC
450
500
550 kHz
210
250
290 kHz
700
770
850 kHz
250
kΩ
9
10
11
µA
60
Deg
90
Deg
120
Deg
4
5
V
0
0.2
V
VPGL
IPGOOD
VPG
PGOOD Voltage Low
PGOOD Leakage Current
PGOOD Trip Level, Either Controller
Differential Amplifier
IPGOOD = 2mA
VPGOOD = 5V
VFB with Respect to Set Output Voltage
VFB Ramping Negative
VFB Ramping Positive
0.1
0.3
V
±2
µA
–10
%
10
%
ADA
RIN
VOS
PSRROA
ICL
VOUT(MAX)
GBW
Gain
Input Resistance
Input Offset Voltage
Power Supply Rejection Ratio
Maximum Output Current
Maximum Output Voltage
Gain Bandwidth Product
Measured at DIFFP Input
VDIFFP = VDIFFOUT = 1.5V, IDIFFOUT = 100µA
5V < VIN < 38V
IDIFFOUT = 300µA
(Note 8)
l 0.998
1
1.002 V/V
80
kΩ
2
mV
100
dB
2
3
mA
VINTVCC – 1.4 VINTVCC – 1.1
V
3
MHz
Slew Rate Differential Amplifier Slew Rate
(Note 8)
2
V/µs
3855f

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