LTC1778EGN-1 Ver la hoja de datos (PDF) - Linear Technology
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LTC1778EGN-1 Datasheet PDF : 24 Pages
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LTC1778/LTC1778-1
ELECTRICAL CHARACTERISTICS The ● denotes specifications which apply over the full operating
temperature range, otherwise specifications are TA = 25°C. VIN = 15V unless otherwise noted.
SYMBOL
PARAMETER
CONDITIONS
MIN TYP MAX
tOFF(MIN)
VSENSE(MAX)
Minimum Off-Time
Maximum Current Sense Threshold
VPGND – VSW
VSENSE(MIN)
Minimum Current Sense Threshold
VPGND – VSW
∆VFB(OV)
Output Overvoltage Fault Threshold
VFB(UV)
Output Undervoltage Fault Threshold
VRUN/SS(ON)
RUN Pin Start Threshold
VRUN/SS(LE)
RUN Pin Latchoff Enable Threshold
VRUN/SS(LT)
RUN Pin Latchoff Threshold
IRUN/SS(C)
Soft-Start Charge Current
IRUN/SS(D)
Soft-Start Discharge Current
VIN(UVLO)
Undervoltage Lockout
VIN(UVLOR)
Undervoltage Lockout Release
TG RUP
TG Driver Pull-Up On Resistance
TG RDOWN
TG Driver Pull-Down On Resistance
BG RUP
BG Driver Pull-Up On Resistance
BG RDOWN
BG Driver Pull-Down On Resistance
TG tr
TG Rise Time
TG tf
TG Fall Time
BG tr
BG Rise Time
BG tf
BG Fall Time
Internal VCC Regulator
VINTVCC
Internal VCC Voltage
∆VLDO(LOADREG) Internal VCC Load Regulation
VEXTVCC
EXTVCC Switchover Voltage
∆VEXTVCC
EXTVCC Switch Drop Voltage
∆VEXTVCC(HYS) EXTVCC Switchover Hysteresis
PGOOD Output (LTC1778 Only)
ION = 30µA
VRNG = 1V, VFB = 0.76V
VRNG = 0V, VFB = 0.76V
VRNG = INTVCC, VFB = 0.76V
VRNG = 1V, VFB = 0.84V
VRNG = 0V, VFB = 0.84V
VRNG = INTVCC, VFB = 0.84V
RUN/SS Pin Rising
RUN/SS Pin Falling
VRUN/SS = 0V
VRUN/SS = 4.5V, VFB = 0V
VIN Falling
VIN Rising
TG High
TG Low
BG High
BG Low
CLOAD = 3300pF
CLOAD = 3300pF
CLOAD = 3300pF
CLOAD = 3300pF
6V < VIN < 30V, VEXTVCC = 4V
ICC = 0mA to 20mA, VEXTVCC = 4V
ICC = 20mA, VEXTVCC Rising
ICC = 20mA, VEXTVCC = 5V
250 400
● 113
133
153
● 79
93
107
● 158
186
214
– 67
– 47
– 93
5.5
7.5
9.5
520
600
680
● 0.8
1.5
2
4
4.5
3.5
4.2
– 0.5 – 1.2
–3
0.8
1.8
3
●
3.4
3.9
●
3.5
4
2
3
2
3
3
4
1
2
20
20
20
20
● 4.7
5
5.3
– 0.1
±2
● 4.5
4.7
150 300
200
∆VFBH
∆VFBL
∆VFB(HYS)
VPGL
PGOOD Upper Threshold
PGOOD Lower Threshold
PGOOD Hysteresis
PGOOD Low Voltage
VFB Rising
VFB Falling
VFB Returning
IPGOOD = 5mA
5.5
7.5
9.5
– 5.5 – 7.5 – 9.5
1
2
0.15
0.4
UNITS
ns
mV
mV
mV
mV
mV
mV
%
mV
V
V
V
µA
µA
V
V
Ω
Ω
Ω
Ω
ns
ns
ns
ns
V
%
V
mV
mV
%
%
%
V
Note 1: Absolute Maximum Ratings are those values beyond which the life of
a device may be impaired.
Note 2: TJ is calculated from the ambient temperature TA and power
dissipation PD as follows:
LTC1778E: TJ = TA + (PD • 130°C/W)
Note 3: The LTC1778 is tested in a feedback loop that adjusts VFB to achieve
a specified error amplifier output voltage (ITH).
Note 4: The LTC1778E is guaranteed to meet performance specifications from
0°C to 70°C. Specifications over the –40°C to 85°C operating temperature
range are assured by design, characterization and correlation with statistical
process controls. The LTC1778I is guaranteed over the full – 40°C to 125°C
operating temperature range.
1778fb
3
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