 English |
|
|
|
|
|
|
|
| LTC3851-1_15 Datasheet, PDF (3/28 Pages) Linear Technology – Synchronous Step-Down Switching Regulator Controller | |||
| |||
| ◁ |
LTC3851-1
ELECTRICAL CHARACTERISTICS The l denotes the speciï¬cations which apply over the full operating
junction temperature range, otherwise speciï¬cations are at TA = 25°C. VIN = 15V, VRUN = 5V unless otherwise noted.
SYMBOL PARAMETER
CONDITIONS
MIN TYP MAX
Main Control Loops
VIN
VFB
IFB
VREFLNREG
VLOADREG
gm
gm GBW
IQ
UVLO
UVLO Hys
Input Operating Voltage Range
Regulated Feedback Voltage
Feedback Current
Reference Voltage Line Regulation
Output Voltage Load Regulation
Transconductance Ampliï¬er gm
Transconductance Amp Gain Bandwidth
Input DC Supply Current
Normal Mode
Shutdown
Undervoltage Lockout on INTVCC
UVLO Hysteresis
ITH = 1.2V (Note 4)
(Note 4)
VIN = 6V to 38V (Note 4)
(Note 4)
Measured in Servo Loop,
ÎITH = 1.2V to 0.7V
(Note 4)
Measured in Servo Loop,
ÎITH = 1.2V to 1.6V
ITH = 1.2V, Sink/Source = 5μA (Note 4)
ITH = 1.2V
(Note 5)
VRUN = 5V
VRUN = 0V
VINTVCC Ramping Down
4
l 0.792
0.800
â10
0.002
38
0.808
â50
0.02
l
0.01
0.1
l
â0.01 â0.1
2
3
1
20
35
3.25
0.4
VOVL
ISENSE
ITK/SS
VRUN
VRUNHYS
VSENSE(MAX)
TG RUP
Feedback Overvoltage Lockout
SENSE Pins Current
Soft-Start Charge Current
RUN Pin On Threshold
RUN Pin On Hysteresis
Maximum Current Sense Threshold
TG Driver Pull-Up On-Resistance
Measured at VFB
VTK/SS = 0V
VRUN Rising
VFB = 0.7V, VSENSE = 3.3V
TG High
l 0.86 0.88 0.90
±1
±2
0.6
1
2
l 1.10 1.25 1.35
130
l 40
50
65
2.6
TG RDOWN TG Driver Pull-Down On-Resistance
TG Low
1.5
BG RUP
BG Driver Pull-Up On-Resistance
BG High
2.4
BG RDOWN BG Driver Pull-Down On-Resistance
BG Low
1.1
TG Transition Time
(Note 6)
TG tr
Rise Time
CLOAD = 3300pF
25
TG tf
Fall Time
CLOAD = 3300pF
25
BG Transition Time
(Note 6)
BG tr
Rise Time
CLOAD = 3300pF
25
BG tf
Fall Time
CLOAD = 3300pF
25
TG/BG t1D Top Gate Off to Bottom Gate On Delay CLOAD = 3300pF Each Driver
30
Bottom Switch-On Delay Time
(Note 6)
BG/TG t2D Bottom Gate Off to Top Gate On Delay CLOAD = 3300pF Each Driver
30
Top Switch-On Delay Time
(Note 6)
tON(MIN)
Minimum On-Time
INTVCC Linear Regulator
VINTVCC
Internal VCC Voltage
VLDO INT
INTVCC Load Regulation
Oscillator and Phase-Locked Loop
(Note 7)
6V < VIN < 38V
ICC = 0mA to 50mA
90
4.8
5
5.2
0.5
fNOM
Nominal Frequency
fLOW
Lowest Frequency
RFREQ = 60k
RFREQ = 160k
480
500
530
220
250
280
UNITS
V
V
nA
%/V
%
%
mmho
MHz
mA
μA
V
V
V
μA
μA
V
mV
mV
Ω
Ω
Ω
Ω
ns
ns
ns
ns
ns
ns
ns
V
%
kHz
kHz
38511fa
3
|
▷ |
German
Russian
Spanish
Italian
Polish
Chinese
Japanese
Korean
French
Portuguese