LTC3856_15 Datasheet, PDF (4/40 Pages) Linear Technology – 2-Phase Synchronous Step-Down DC/DC Controller with Diffamp

LTC3856
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
BG1,2 t_r
BG1,2 t_f
TG/BG t_1D
TG Transition Time
Rise Time
Fall Time
BG Transition Time
Rise Time
Fall Time
Top Gate Off to Bottom Gate On Delay
Synchronous Switch-On Delay Time
(Note 6)
C_LOAD = 3300pF
C_LOAD = 3300pF
(Note 6)
C_LOAD = 3300pF
C_LOAD = 3300pF
C_LOAD = 3300pF Each Driver
25
ns
25
ns
25
ns
25
ns
30
ns
BG/TG t_2D Bottom Gate Off to Top Gate On Delay C_LOAD = 3300pF Each Driver
Top Switch-On Delay Time
30
ns
t_ON(MIN)
Minimum On-Time
INTV_CC Linear Regulator
V_INTVCC
Internal V_CC Voltage
V_LDO INT INTV_CC Load Regulation
V_EXTVCC
EXTV_CC Switchover Voltage
V_LDO EXT EXTV_CC Voltage Drop
V_LDOHYS
EXTV_CC Hysteresis
Oscillator and Phase-Locked Loop
(Note 7)
6V < V_IN ≤ 38V
I_CC = 0mA to 20mA
EXTV_CC Ramping Positive
I_CC = 20mA, V_EXTVCC = 5V
90
ns
4.8 5.0 5.2
V
0.5 2.0
%
l 4.5 4.7
V
50 100
mV
200
mV
f_NOM
f_LOW
f_HIGH
R_MODE
I_FREQ
CLKOUT
Nominal Frequency
Lowest Frequency
Highest Frequency
MODE Input Resistance
Frequency Setting Output Current
Phase (Relative to Controller 1)
V_FREQ = 1.2V
V_FREQ = 0V
V_FREQ ≥ 2.4V
PHASMD = GND; Non Stage Shedding Mode
PHASMD = FLOAT; Non Stage Shedding Mode
PHASMD = INTV_CC; Non Stage Shedding Mode
Stage Shedding Mode
450 500 550
kHz
210 250 290
kHz
700 770 850
kHz
250
kΩ
9
10 11
µA
60
Deg
90
Deg
120
Deg
180
Deg
CLKHIGH Clock High Output Voltage
4
5
V
CLKLOW Clock Low Output Voltage
0 0.2
V
PGOOD Output
V_PGL
I_PGOOD
V_PG
PGOOD Voltage Low
PGOOD Leakage Current
PGOOD Trip Level, Either Controller
I_PGOOD = 2mA
V_PGOOD = 5V
V_FB with Respect to Set Output Voltage
V_FB Ramping Negative
V_FB Ramping Positive
0.1 0.2
V
±2
µA
–10
%
10
%
3856f