Datasheet

LTC3855
4
3855f
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
TG/BG t
1D
Top Gate Off to Bottom Gate On Delay
Synchronous Switch-On Delay Time
C
LOAD
= 3300pF Each Driver 30 ns
BG/TG t
2D
Bottom Gate Off to Top Gate On Delay
Top Switch-On Delay Time
C
LOAD
= 3300pF Each Driver 30 ns
t
ON(MIN)
Minimum On-Time (Note 7) 90 ns
INTV
CC
Linear Regulator
V
INTVCC
Internal V
CC
Voltage 6V < V
IN
< 38V 4.8 5 5.2 V
V
LDO
INT INTV
CC
Load Regulation I
CC
= 0mA to 20mA 0.5 2 %
V
EXTVCC
EXTV
CC
Switchover Voltage EXTV
CC
Ramping Positive
l
4.5 4.7 V
V
LDO
EXT EXTV
CC
Voltage Drop I
CC
= 20mA, V
EXTVCC
= 5V 50 100 mV
V
LDOHYS
EXTV
CC
Hysteresis 200 mV
Oscillator and Phase-Locked Loop
f
NOM
Nominal Frequency V
FREQ
= 1.2V 450 500 550 kHz
f
LOW
Lowest Frequency V
FREQ
= 0V 210 250 290 kHz
f
HIGH
Highest Frequency V
FREQ
≥ 2.4V 700 770 850 kHz
R
MODE/PLLIN
MODE/PLLIN Input Resistance 250 kΩ
I
FREQ
Frequency Setting Current 9 10 11 µA
CLKOUT Phase (Relative to Controller 1) PHASMD = GND
PHASMD = Float
PHASMD = INTV
CC
60
90
120
Deg
Deg
Deg
CLK
HIGH
Clock High Output Voltage 4 5 V
CLK
LOW
Clock Low Output Voltage 0 0.2 V
PGOOD Output
V
PGL
PGOOD Voltage Low I
PGOOD
= 2mA 0.1 0.3 V
I
PGOOD
PGOOD Leakage Current V
PGOOD
= 5V ±2 µA
V
PG
PGOOD Trip Level, Either Controller V
FB
with Respect to Set Output Voltage
V
FB
Ramping Negative
V
FB
Ramping Positive
–10
10
%
%
Differential Amplifier
A
DA
Gain
l
0.998 1 1.002 V/V
R
IN
Input Resistance Measured at DIFFP Input 80 kΩ
V
OS
Input Offset Voltage V
DIFFP
= V
DIFFOUT
= 1.5V, I
DIFFOUT
= 100µA 2 mV
PSRR
OA
Power Supply Rejection Ratio 5V < V
IN
< 38V 100 dB
I
CL
Maximum Output Current 2 3 mA
V
OUT(MAX)
Maximum Output Voltage I
DIFFOUT
= 300µA V
INTVCC
– 1.4 V
INTVCC
– 1.1 V
GBW Gain Bandwidth Product (Note 8) 3 MHz
Slew Rate Differential Amplifier Slew Rate (Note 8) 2 V/µs
elecTrical characTerisTics
The l denotes the specifications which apply over the full operating
junction temperature range (E-Grade), otherwise specifications are at T
A
= 25°C. V
IN
= 15V, V
RUN1,2
= 5V unless otherwise noted.