Datasheet

LTC3856
4
3856f
elecTrical characTerisTics
The l denotes the specifications which apply over the full operating
junction temperature range, otherwise specifications are at T
A
= 25°C (Note 2). V
IN
= 15V, V
RUN
= 5V, unless otherwise noted.
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
TG1,2 t
r
TG1,2 t
f
TG Transition Time
Rise Time
Fall Time
(Note 6)
C
LOAD
= 3300pF
C
LOAD
= 3300pF
25
25
ns
ns
BG1,2 t
r
BG1,2 t
f
BG Transition Time
Rise Time
Fall Time
(Note 6)
C
LOAD
= 3300pF
C
LOAD
= 3300pF
25
25
ns
ns
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 5.0 5.2 V
V
LDO
INT INTV
CC
Load Regulation I
CC
= 0mA to 20mA 0.5 2.0 %
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
MODE Input Resistance 250 kΩ
I
FREQ
Frequency Setting Output Current 9 10 11 µA
CLKOUT Phase (Relative to Controller 1) PHASMD = GND; Non Stage Shedding Mode
PHASMD = FLOAT; Non Stage Shedding Mode
PHASMD = INTV
CC
; Non Stage Shedding Mode
Stage Shedding Mode
60
90
120
180
Deg
Deg
Deg
Deg
CLKHIGH Clock High Output Voltage 4 5 V
CLKLOW Clock Low Output Voltage 0 0.2 V
PGOOD Output
V
PGL
PGOOD Voltage Low I
PGOOD
= 2mA 0.1 0.2 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
%
%