Datasheet

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ELECTRICAL CHARACTERISTICS
UC1879
UC2879
UC3879
SLUS230B – JUNE 1998 – REVISED JUNE 2007
Unless specified; VC = VIN = V
UVSEL
= 12 V, CT = 470 pF, RT = 9.53k, R
DELSETA-B
= R
DELSEC-D
= 4.8k, C
DELSETA-B
= C
DELSETC-D
= 0.01 µ F, T
A
= T
J
.
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
Undervoltage Lockout
V
UVSEL
= VIN 9 10.75 12.5
Start threshold
V
UVSEL
= Open 12.5 15.25 16.5
V
V
UVSEL
= VIN 1.15 1.75 2.15
UVLO hysteresis
V
UVSEL
= Open 5.2 6 7.4
Input bias, UVSEL pin V
UVSEL
= VIN = 8 V 30 µ A
Supply Current
VIN = V
UVSEL
= 8 V, VC = 18 V,
I
VIN
startup 150 600
I
DELSETA-B
= I
DELSETC-D = 0
µ A
VIN = V
UVSEL
= 8 V, VC = 18 V,
I
VC
startup 10 100
I
DELSETA-B
= I
DELSETC-D = 0
UC3879, UC2879 23 35
I
VIN
operating
UC1879 23 36 mA
I
VC
operating 4 8
Voltage Reference
Output voltage T
J
= 25 ° C 4.92 5 5.08 V
Line regulation 11 V < VIN < 18 V 1 10
mV
Load regulation I
VREF
= –10 mA 5 20
Total variation Line, Load, Temperature 4.875 5.125 V
Short circuit current VREF = 0 V, T
J
= 25 ° C –60 –15 mA
Error Amplifier
Error amplifier input voltage 2.4 2.5 2.6 V
Input bias current 0.6 3 µ A
AVOL 1 V < VCOMP < 4 V 60 90
dB
PSRR 11 V < VIN < 18 V 85 100
Output sink current V
COMP
= 1 V 1 2.5
mA
Output source current V
COMP
= 4 V –1.3 –0.5
Output voltage high I
COMP
= –0.5 mA 4 4.7 5
V
Output voltage low I
COMP
= 1 mA 0 0.5 1
Slew rate T
A
= 25 ° C 6 11 V/ µ s
4
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