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SLUS334C − AUGUST 1995 − REVISED AUGUST 2004
ELECTRICAL CHARACTERISTICS
T
R
= −55°C to 125°C for the UC1823A/UC1825A, T = −40°C to 85°C for the UC2823x/UC2825x, T = 0°C to 70°C for the UC3823x/UC3825x,
A A
A
T
= 3.65 kΩ, C = 1 nF, V = 12 V, T = T (unless otherwise noted)
T
CC A J
PWM COMPARATOR
I
Bias current, RAMP
V
= 0 V
−1
−8
µA
BIAS
RAMP
Minimum duty cycle
0%
Maximum duty cycle
Leading edge blanking time
85%
300
8.5
t
R
= 2 kΩ,
C
= 470 pF
375
10.0
1.25
50
450
11.5
1.4
ns
kΩ
V
LEB
LEB
LEB
R
Leading edge blanking resistance
V
V
V
= 3 V
LEB
CLK/LEB
V
Zero dc threshold voltage, EAOUT
Delay-to-output time
= 0 V
1.10
ZDC
RAMP
t
= 2.1 V,
V = 0 V to 2 V step
ILIM
80
ns
DELAY
EAOUT
CURRENT LIMIT / START SEQUENCE / FAULT
I
Soft-start charge current
Full soft-start threshold voltage
Restart discharge current
Restart threshold voltage
ILIM bias current
V
V
V
= 2.5 V
8
4.3
14
5
20
µA
V
SS
SS
V
SS
DSCH
SS
I
I
I
I
= 2.5 V
SS
100
250
0.3
350
0.5
µA
V
= 0 V to 2 V step
= 0 V to 2 V step
15
µA
BIAS
CL
ILIM
Current limit threshold voltage
Overcurrent threshold voltage
0.95
1.14
1
1.2
50
1.05
1.26
80
V
(1)
Delay-to-output time, ILIM
t
d
V
ILIM
ns
OUTPUT
I
I
I
I
= 20 mA
= 200 mA
= 20 mA
= 200 mA
0.25
1.2
1.9
2
0.4
2.2
2.9
3
OUT
OUT
OUT
OUT
Low-level output saturation voltage
High-level output saturation voltage
V
t
r,
t
f
(1)
Rise/fall time
C
L
= 1 nF
20
45
ns
UNDERVOLTAGE LOCKOUT (UVLO)
Start threshold voltage
Stop threshold voltage
OVLO hysteresis
UC2823B, UC2825B, UC3825B, UC3825B
16
9.2
10
0.8
6
17
UC1823A, UC1825A, UC2823A, UC2825A
UC3825A, UC3825A
8.4
9
9.6
UC2823B, UC2825B, UC3825B, UC3825B
V
UC1823A, UC1825A, UC2823A, UC2825A
UC3825A, UC3825A
0.4
5
1.2
7
UC2823B, UC2825B, UC3825B, UC3825B
SUPPLY CURRENT
I
I
Startup current
Input current
VC = VCC = V
TH
= −0.5 V
100
28
300
36
µA
su
mA
CC
(1)
Ensured by design. Not production tested.
5
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