LTC3851_15 Datasheet, PDF (3/28 Pages) Linear Technology – Synchronous Step-Down Switching Regulator Controller

LTC3851
ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T_A = 25°C. V_IN = 15V, V_RUN = 5V unless otherwise noted.
SYMBOL PARAMETER
CONDITIONS
MIN TYP MAX UNITS
Main Control Loops
V_IN
V_FB
I_FB
V_REFLNREG
V_LOADREG
g_m
g_m GBW
I_Q
UVLO
UVLO Hys
Operating Input Voltage Range
Regulated Feedback Voltage
Feedback Current
I_TH = 1.2V (Note 4)
(Note 4)
Reference Voltage Line Regulation
Output Voltage Load Regulation
Transconductance Amplifier g_m
Transconductance Amp Gain Bandwidth
Input DC Supply Current
Normal Mode
Shutdown
Undervoltage Lockout on INTV_CC
UVLO Hysteresis
V_IN = 6V to 38V (Note 4)
(Note 4)
Measured in Servo Loop,
ΔI_TH = 1.2V to 0.7V
(Note 4)
Measured in Servo Loop,
ΔI_TH = 1.2V to 1.6V
I_TH = 1.2V, Sink/Source = 5μA (Note 4)
I_TH = 1.2V
(Note 5)
V_RUN = 5V
V_RUN = 0V
V_INTVCC Ramping Down
l
4
38
V
l 0.792 0.800 0.808
V
–10
–50
nA
0.002 0.02
%/V
l
0.01
0.1
%
l
–0.01 –0.1
%
2
mmho
3
MHz
1.2
mA
20
35
μA
3.25
V
0.4
V
V_OVL
I_SENSE
I_TK/SS
V_RUN
V_RUNHYS
V_SENSE(MAX)
Feedback Overvoltage Lockout
SENSE Pins Current
Soft-Start Charge Current
RUN Pin On Threshold
RUN Pin On Hysteresis
Maximum Current Sense Threshold
TG R_UP
TG R_DOWN
BG R_UP
BG R_DOWN
TG t_r
TG t_f
BG tr
BG tf
TG/BG t_1D
TG Driver Pull-Up On-Resistance
TG Driver Pull-Down On-Resistance
BG Driver Pull-Up On-Resistance
BG Driver Pull-Down On-Resistance
TG Transition Time
Rise Time
Fall Time
BG Transition Time
Rise Time
Fall Time
Top Gate Off to Bottom Gate On Delay
Bottom Switch-On Delay Time
Measured at V_FB
V_TK/SS = 0V
V_RUN Rising
V_FB = 0.7V, V_SENSE = 3.3V, I_LIM = 0V
V_FB = 0.7V, V_SENSE = 3.3V, I_LIM = Float
V_FB = 0.7V, V_SENSE = 3.3V, I_LIM = INTV_CC
TG High
TG Low
BG High
BG Low
(Note 6)
C_LOAD = 3300pF
C_LOAD = 3300pF
(Note 6)
C_LOAD = 3300pF
C_LOAD = 3300pF
C_LOAD = 3300pF Each Driver
(Note 6)
l 0.86 0.88 0.90
V
±1
±2
μA
0.6
1
2
μA
l 1.10 1.25 1.35
V
130
mV
l 20
30
40
mV
l 40
50
65
mV
l 65
75
90
mV
2.6
Ω
1.5
Ω
2.4
Ω
1.1
Ω
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
(Note 6)
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
(Note 7)
6V < V_IN < 38V
I_CC = 0mA to 50mA
90
ns
4.8
5
5.2
V
0.5
2
%
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