UC3844B, UC3845B, UC2844B, UC2845B
MAXIMUM RATINGS
Rating
Symbol
Value
Unit
mA
A
Total Power Supply and Zener Current
Output Current, Source or Sink (Note 1)
Output Energy (Capacitive Load per Cycle)
Current Sense and Voltage Feedback Inputs
Error Amp Output Sink Current
(I + I )
30
CC
Z
I
O
1.0
5.0
W
mJ
V
in
− 0.3 to + 5.5
10
V
I
O
mA
Power Dissipation and Thermal Characteristics
D Suffix, Plastic Package, SOIC−14 Case 751A
Maximum Power Dissipation @ T = 25°C
Thermal Resistance, Junction−to−Air
P
862
145
mW
°C/W
A
D
R
q
JA
D1 Suffix, Plastic Package, SOIC−8 Case 751
Maximum Power Dissipation @ T = 25°C
Thermal Resistance, Junction−to−Air
N Suffix, Plastic Package, Case 626
P
702
178
mW
°C/W
A
D
R
q
JA
Maximum Power Dissipation @ T = 25°C
Thermal Resistance, Junction−to−Air
P
1.25
100
W
°C/W
A
D
R
q
JA
Operating Junction Temperature
T
+150
°C
°C
J
Operating Ambient Temperature
UC3844B, UC3845B
T
A
0 to + 70
UC2844B, UC2845B
− 25 to + 85
Storage Temperature Range
T
stg
− 65 to +150
°C
Maximum ratings are those values beyond which device damage can occur. Maximum ratings applied to the device are individual stress limit
values (not normal operating conditions) and are not valid simultaneously. If these limits are exceeded, device functional operation is not implied,
damage may occur and reliability may be affected.
1. Maximum package power dissipation limits must be observed.
ELECTRICAL CHARACTERISTICS (V = 15 V [Note 2], R = 10 k, C = 3.3 nF. For typical values T = 25°C, for min/max values
CC
T
T
A
T is the operating ambient temperature range that applies [Note 3], unless otherwise noted.)
A
UC284XB
UC384XB, XBV
Characteristic
REFERENCE SECTION
Reference Output Voltage (I = 1.0 mA, T = 25°C)
Symbol
Min
Typ
Max
Min
Typ
Max
Unit
V
ref
4.95
−
5.0
2.0
3.0
0.2
−
5.05
20
25
−
4.9
−
5.0
2.0
3.0
0.2
−
5.1
20
V
mV
mV
mV/°C
V
O
J
Line Regulation (V = 12 V to 25 V)
Reg
CC
line
load
S
Load Regulation (I = 1.0 mA to 20 mA)
Reg
−
−
25
O
Temperature Stability
T
−
−
−
Total Output Variation over Line, Load, and Temperature
Output Noise Voltage (f = 10 Hz to 10 kHz, T = 25°C)
V
ref
4.9
−
5.1
−
4.82
−
5.18
−
V
n
50
50
mV
J
Long Term Stability (T = 125°C for 1000 Hours)
S
−
5.0
− 85
−
−
5.0
− 85
−
mV
mA
A
Output Short Circuit Current
I
− 30
−180
− 30
−180
SC
OSCILLATOR SECTION
Frequency
f
kHz
OSC
T = 25°C
49
48
52
−
55
56
49
48
52
−
55
56
J
T = T
to T
high
A
low
T = 25°C (R = 6.2 k, C = 1.0 nF)
225
250
275
225
250
275
J
T
T
Frequency Change with Voltage (V = 12 V to 25 V)
Df
Df
/DV
/DT
−
−
−
0.2
1.0
1.6
1.0
−
−
−
−
0.2
0.5
1.6
1.0
−
%
%
CC
OSC
Frequency Change with Temperature (T = T
to T
)
A
low
high
OSC
Oscillator Voltage Swing (Peak−to−Peak)
V
−
−
V
OSC
Discharge Current (V
= 2.0 V)
I
mA
OSC
dischg
T = 25°C
7.8
7.5
−
8.3
−
−
8.8
8.8
−
7.8
7.6
7.2
8.3
−
−
8.8
8.8
8.8
J
T = T
to T
to T
(UC284XB, UC384XB)
(UC384XBV)
A
low
low
high
high
T = T
A
2. Adjust V above the Startup threshold before setting to 15 V.
CC
3. Low duty cycle pulse techniques are used during test to maintain junction temperature as close to ambient as possible.
T
low
= 0°C for UC3844B, UC3845B
= − 25°C for UC2844B, UC2845B
= − 40°C for UC3844BV, UC3845BV
T
= + 70°C for UC3844B, UC3845B
= + 85°C for UC2844B, UC2845B
= +105°C for UC3844BV, UC3845BV
high
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