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UC3854N-F Datasheet, PDF (3/12 Pages) Texas Instruments – High Power Factor Preregulator
UC1854
UC2854
UC3854
ELECTRICAL
CHARACTERISTICS
Unless otherwise stated, VCC=18V, RSET=15k to ground, CT=1.5nF to ground, PKLMT=1V, ENA=7.5V,
VRMS=1.5V, IAC=100µA, ISENSE=0V, CA Out=3.5V, VA Out=5V, VSENSE=7.5V, no load on SS, CA Out,
VA Out, REF, GT Drv, –55oC<TA<125oC for the UC1854, –40oC<TA<85oC for the UC2854, and
0oC<TA<70oC for the UC3854, and TA=TJ.
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX UNITS
CURRENT AMPLIFIER
Current Amp Offset Voltage
–4
4
mV
ISENSE Bias Current
–500
–120
500
nA
Input Range, ISENSE, Mult Out
–0.3 to 2.5
V
Current Amp Gain
80
110
dB
Current Amp Output Swing
0.5 to 16
V
Current Amp Short Circuit Current CA Out=0V
Current Amp Gain-BW Product TA=25oC (Note 6)
–36
–20
400
800
–5
mA
kHz
REFERENCE
Reference Output Voltage
IREF=0mA, TA=25oC
7.4
7.5
7.6
V
IREF=0mA, Over Temp.
7.35
7.5
7.65
V
VREF Load Regulation
–10mA<IREF<0mA
–15
5
15
mV
VREF Line Regulation
15V<VCC<35V
–10
2
10
mV
VREF Short Circuit Current
REF=0V
–50
–28
–12
mA
MULTIPLIER
Mult Out Current IAC Limited
IAC=100µA, RSET=10k, VRMS=1.25V
–220
–200
–180
µA
Mult Out Current Zero
IAC=0µA, RSET=15k
–2.0
–0.2
2.0
µA
Mult Out Current RSET Limited
IAC=450µA, RSET=15k, VRMS=1V, VA Out = 6V –280
–255
–220
µA
Mult Out Current
IAC=50µA, VRMS=2V, VA=4V
–50
–42
–33
µA
IAC=100µA, VRMS=2V, VA=2V
IAC=200µA, VRMS=2V, VA=4V
–38
–27
–12
µA
–165
–150
–105
µA
IAC=300µA, VRMS=1V, VA=2V
–250
–225
–150
µA
IAC=100µA, VRMS=1V, VA=2V
–95
–80
–60
µA
Multiplier Gain Constant
(Note 5)
–1.0
V
OSCILLATOR
Oscillator Frequency
RSET=15k
46
55
62
kHz
RSET=8.2k
86
102
118
kHz
CT Ramp Peak-to-Valley Amplitude
4.9
5.4
5.9
V
CT Ramp Valley Voltage
0.8
1.1
1.3
V
GATE DRIVER
Maximum GT Drv Output Voltage 0mA load on GT Drv, 18V<VCC<35V
13
14.5
18
V
GT Drv Output Voltage High
–200mA load on GT Drv, VCC=15V
12
12.8
V
GT Drv Output Voltage Low, Off VCC=0V, 50mA load on GT Drv
0.9
1.5
V
GT Drv Output Voltage Low
200mA load on GT Drv
1.0
2.2
V
10mA load on GT Drv
0.1
0.4
V
Peak GT Drv Current
10nF from GT Drv to Gnd
1.0
A
GT Drv Rise/Fall Time
1nF from GT Drv to Gnd
35
ns
GT Drv Maximum Duty Cycle
VCA Out=7V
95
%
CURRENT LIMIT
PKLMT Offset Voltage
–10
10
mV
PKLMT Input Current
PKLMT=–0.1V
–200
–100
µA
PKLMT to GT Drv Delay
PKLMT falling from 50mV to –50mV
175
ns
Note 5: Multiplier Gain Constant (k) is defined by:
IMult
Out
=
k
×
IAC × (VA Out−1)
VRMS2
Note 6: Guaranteed by design. Not 100% tested in production.
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