UC2845BVD1R2G View Datasheet(PDF) - ON Semiconductor
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UC2845BVD1R2G Datasheet PDF : 19 Pages
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UC3844B, UC3845B, UC2844B, UC2845B
ELECTRICAL CHARACTERISTICS (VCC = 15 V [Note 7], RT = 10 k, CT = 3.3 nF. For typical values TA = 25°C, for min/max values
TA is the operating ambient temperature range that applies [Note 8], unless otherwise noted.)
UC284xB
UC384xB, xBV,
NCV384xBV
Characteristic
Symbol Min Typ Max Min Typ Max Unit
OSCILLATOR SECTION
Discharge Current (VOSC = 2.0 V)
TJ = 25°C
TA = Tlow to Thigh (UC284XB, UC384XB)
(UC384XBV)
Idischg
7.8 8.3 8.8 7.8 8.3 8.8 mA
7.5
−
8.8 7.6
−
8.8
−
−
−
7.2
−
8.8
ERROR AMPLIFIER SECTION
Voltage Feedback Input (VO = 2.5 V)
Input Bias Current (VFB = 5.0 V)
Open Loop Voltage Gain (VO = 2.0 V to 4.0 V)
Unity Gain Bandwidth (TJ = 25°C)
Power Supply Rejection Ratio (VCC = 12 V to 25 V)
Output Current − Sink (VO = 1.1 V, VFB = 2.7 V)
Output Current − Source (VO = 5.0 V, VFB = 2.3 V)
Output Voltage Swing
High State (RL = 15 k to ground, VFB = 2.3 V)
Low State (RL = 15 k to Vref, VFB = 2.7 V)
(UC284XB, UC384XB)
(UC384XBV)
VFB
IIB
AVOL
BW
PSRR
ISink
ISource
VOH
VOL
2.45 2.5 2.55 2.42 2.5 2.58 V
− − 0.1 −1.0 − − 0.1 − 2.0 mA
65
90
−
65
90
−
dB
0.7 1.0
−
0.7 1.0
− MHz
60
70
−
60
70
−
dB
2.0 12
−
2.0 12
− mA
− 0.5 −1.0 − − 0.5 −1.0 −
V
5.0 6.2
−
5.0 6.2
−
−
0.8 1.1
−
0.8 1.1
−
−
−
−
0.8 1.2
CURRENT SENSE SECTION
Current Sense Input Voltage Gain (Notes 9 & 10)
(UC284XB, UC384XB)
(UC384XBV)
AV
V/V
2.85 3.0 3.15 2.85 3.0 3.15
−
−
− 2.85 3.0 3.25
Maximum Current Sense Input Threshold (Note 9)
(UC284XB, UC384XB)
(UC384XBV)
Vth
V
0.9 1.0 1.1 0.9 1.0 1.1
−
−
− 0.85 1.0 1.1
Power Supply Rejection Ratio (VCC = 12 V to 25 V) (Note 9)
Input Bias Current
Propagation Delay (Current Sense Input to Output)
PSRR
−
70
−
IIB
− − 2.0 −10
tPLH(In/Out)
−
150 300
−
70
−
dB
− − 2.0 −10 mA
−
150 300 ns
OUTPUT SECTION
Output Voltage
Low State (ISink = 20 mA)
(ISink = 200 mA, UC284XB, UC384XB)
(ISink = 200 mA, UC384XBV)
High State (ISource = 20 mA, UC284XB, UC384XB)
(ISource = 20 mA, UC384XBV)
(ISource = 200 mA)
V
VOL
−
0.1 0.4
−
0.1 0.4
−
1.6 2.2
−
1.6 2.2
−
−
−
−
1.6 2.3
VOH
13 13.5 −
13 13.5 −
−
−
− 12.9 −
−
12 13.4 −
12 13.4 −
Output Voltage with UVLO Activated (VCC = 6.0 V, ISink = 1.0 mA) VOL(UVLO) −
0.1 1.1
−
0.1 1.1 V
Output Voltage Rise Time (CL = 1.0 nF, TJ = 25°C)
tr
−
50 150
−
50 150 ns
Output Voltage Fall Time (CL = 1.0 nF, TJ = 25°C)
tf
−
50 150
−
50 150 ns
UNDERVOLTAGE LOCKOUT SECTION
Startup Threshold
UCX844B, BV
Vth
UCX845B, BV
15
16
17 14.5 16 17.5 V
7.8 8.4 9.0 7.8 8.4 9.0
Minimum Operating Voltage After Turn−On
UCX844B, BV VCC(min) 9.0
10
11
8.5 10 11.5 V
UCX845B, BV
7.0 7.6 8.2 7.0 7.6 8.2
7. Adjust VCC above the Startup threshold before setting to 15 V.
8. Low duty cycle pulse techniques are used during test to maintain junction temperature as close to ambient as possible.
Tlow = 0°C for UC3844B, UC3845B
= − 25°C for UC2844B, UC2845B
Thigh = + 70°C for UC3844B, UC3845B
= + 85°C for UC2844B, UC2845B
= − 40°C for UC384xBV, NCV384xBV
= +105°C for UC3844BV, UC3845BV
= +125°C for NCV384xBV
9. This parameter is measured at the latch trip point with VFB = 0 V.
10. Comparator gain is defined as: AV =
DV Output/Compensation
DV Current Sense Input
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