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LTC3705 Datasheet, PDF (3/20 Pages) Linear Technology – 2-Switch Forward Controller and Gate Driver | |||
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LTC3705
ELECTRICAL CHARACTERISTICS The â denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. VCC = VBOOST = 12V, GND = PGND = VTS = 0V, TA = 25°C, unless
otherwise noted.
SYMBOL
PARAMETER
CONDITIONS
MIN TYP MAX UNITS
IHUVLO
Hysteresis Current
VUVLOOP
Voltage Feedforward Operating Range
Gate Drivers (TG and BG)
VUVLO = 1V
Primary-Side Control
â 4.2
4.9
5.6
µA
VUVLOF(MIN)
3.75
V
ROS
VOH
IPU
tr
tf
Rectifier
Output Pull-Down Resistance
High Output Voltage
Peak Pull-Up Current
Output Rise Time
Output Fall Time
IOUT = 100mA
IOUT = â100mA
10% to 90%, COUT = 4.7nF
10% to 90%, COUT = 4.7nF
1.9
â¦
11
V
1.7
A
40
ns
70
ns
IRECT
Oscillator
Maximum Rectifier DC Output Current
25
mA
fOSC(P)
Oscillator Frequency
âfRFS(P)
Oscillator Resistor Set Accuracy
fOSC(S)
Oscillator Frequency
Soft-Start/Fault (SSFLT)
Primary-Side Control, RFS(P) = 100kâ¦
Primary-Side Control, RFS(P) = 25kâ¦
Primary-Side Control, RFS(P) = 300kâ¦
Primary-Side Control
25k < RFSET < 300k
Secondary-Side Control (During Start-Up),
RFS(S) = 100kâ¦
200
kHz
700
kHz
70
kHz
±15
%
300
kHz
ISS(C)
Soft-Start Charge Current
VLRTO
Linear Regulator Time Out-Threshold
VFLTH
Fault Output High
ISS(D)
Soft-Start Discharge Current
Current Sense Input (IS)
VIS(MAX)
Overcurrent Threshold
Volt Second Limit (VSLMT)
VVSL(MAX) Volt-Second Limit Threshold
IVSLMT(MAX) Maximum Volt-Second Limit Resistor Current
Optoisolator Bias Current
Primary-Side Control, VSSFLT = 2V
Secondary-Side Control, VUVLO = 1.3V,
VSSFLT = 2V
Secondary-Side Control, VUVLO = 3.75V,
VSSFLT = 2V
VCC = 8V
Timing Out After Fault, VSSFLT = 2V
â 5.2
µA
â4
µA
â 1.6
µA
3.9
V
6.7
V
1
µA
300
mV
1.26
V
0.25
mA
VOPTO
IOPTO
Open Circuit Optoisolator Voltage
Optoisolator Bias Current
Primary-Side Control IFB = 0V
Primary-Side Control VFB = 2.5V
Primary-Side Control VFB = 0V
3.3
V
0.5
mA
1.6
mA
Note 1: Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
Note 2: Operating junction temperature TJ (in °C) is calculated from the
ambient temperature TA and the average power dissipation PD (in watts)
by the formula: TJ = TA + θJA ⢠PD. Refer to the Applications Information
section for details.
Note 3: ICC is the sum of current into NDRV and VCC.
Note 4: The LTC3705EGN is guaranteed to meet performance
specifications from 0°C to 85°C. Specifications over the â40°C to 85°C
operating temperature range are assured by design, characterization and
correlation with statistical process controls. The LTC3705IGN is
guaranteed and tested over the â 40°C to 85°C operating temperature
range.
3705fb
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