Datasheet

UC1823A, UC2823A, UC2823B,
UC3823A, UC3823B, UC1825A,
UC2825A, UC2825B, UC3825A, UC3825B
SLUS334E − AUGUST 1995 − REVISED SEPTEMBER 2010
www.ti.com
5
ELECTRICAL CHARACTERISTICS
T
A
= −55°C to 125°C for the UC1823A/UC1825A, T
A
= −40°C to 85°C for the UC2823x/UC2825x, T
A
= 0°C to 70°C for the UC3823x/UC3825x,
R
T
= 3.65 kΩ, C
T
= 1 nF, V
CC
= 12 V, T
A
= T
J
(unless otherwise noted)
PWM COMPARATOR
I
BIAS
Bias current, RAMP V
RAMP
= 0 V −1 −8 μA
Minimum duty cycle 0%
Maximum duty cycle 85%
t
LEB
Leading edge blanking time R
LEB
= 2 kΩ, C
LEB
= 470 pF 300 375 450 ns
R
LEB
Leading edge blanking resistance V
CLK/LEB
= 3 V 8.5 10.0 11.5 kΩ
V
ZDC
Zero dc threshold voltage, EAOUT V
RAMP
= 0 V 1.10 1.25 1.4 V
t
DELAY
Delay-to-output time
(1)
V
EAOUT
= 2.1 V, V
ILIM
= 0 V to 2 V step 50 80 ns
CURRENT LIMIT / START SEQUENCE / FAULT
I
SS
Soft-start charge current V
SS
= 2.5 V 8 14 20 μA
V
SS
Full soft-start threshold voltage 4.3 5 V
I
DSCH
Restart discharge current V
SS
= 2.5 V 100 250 350 μA
I
SS
Restart threshold voltage 0.3 0.5 V
I
BIAS
ILIM bias current V
ILIM
= 0 V to 2 V step 15 μA
I
CL
Current limit threshold voltage 0.95 1 1.05
V
Overcurrent threshold voltage 1.14 1.2 1.26
V
t
d
Delay-to-output time, ILIM
(1)
V
ILIM
= 0 V to 2 V step 50 80 ns
OUTPUT
Low level output saturation voltage
I
OUT
= 20 mA 0.25 0.4
Low-level output saturation voltage
I
OUT
= 200 mA 1.2 2.2
V
High level output saturation voltage
I
OUT
= 20 mA 1.9 2.9
V
High-level output saturation voltage
I
OUT
= 200 mA 2 3
t
r,
t
f
Rise/fall time
(1)
C
L
= 1 nF 20 45 ns
UNDERVOLTAGE LOCKOUT (UVLO)
UC2823B, UC2825B, UC3825B, UC3825B 16 17
Start threshold voltage
UC1823A, UC1825A, UC2823A, UC2825A
UC3825A, UC3825A
8.4 9.2 9.6
Stop threshold voltage UC2823B, UC2825B, UC3825B, UC3825B 9 10
V
OVLO h
y
steresis
UC1823A, UC1825A, UC2823A, UC2825A
UC3825A, UC3825A
0.4 0.8 1.2
V
OVLO hysteresis
UC2823B, UC2825B, UC3825B, UC3825B 5 6 7
SUPPLY CURRENT
I
su
Startup current VC = VCC = V
TH
(start) − 0.5 V 100 300 μA
I
CC
Input current 28 36 mA
(1)
Ensured by design. Not production tested.