UC3844B, UC3845B, UC2844B, UC2845B
MAXIMUM RATINGS
Rating
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
Power Dissipation and Thermal Characteristics
D Suffix, Plastic Package, SOIC−14 Case 751A
Maximum Power Dissipation @ T
A
= 25°C
Thermal Resistance, Junction−to−Air
D1 Suffix, Plastic Package, SOIC−8 Case 751
Maximum Power Dissipation @ T
A
= 25°C
Thermal Resistance, Junction−to−Air
N Suffix, Plastic Package, Case 626
Maximum Power Dissipation @ T
A
= 25°C
Thermal Resistance, Junction−to−Air
Operating Junction Temperature
Operating Ambient Temperature
UC3844B, UC3845B
UC2844B, UC2845B
Storage Temperature Range
Symbol
(I
CC
+ I
Z
)
I
O
W
V
in
I
O
Value
30
1.0
5.0
− 0.3 to + 5.5
10
Unit
mA
A
mJ
V
mA
P
D
R
qJA
P
D
R
qJA
P
D
R
qJA
T
J
T
A
862
145
702
178
1.25
100
+150
0 to + 70
− 25 to + 85
mW
°C/W
mW
°C/W
W
°C/W
°C
°C
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
CC
= 15 V [Note 2], R
T
= 10 k, C
T
= 3.3 nF. For typical values T
A
= 25°C, for min/max values
T
A
is the operating ambient temperature range that applies [Note 3], unless otherwise noted.)
UC284XB
Characteristic
REFERENCE SECTION
Reference Output Voltage (I
O
= 1.0 mA, T
J
= 25°C)
Line Regulation (V
CC
= 12 V to 25 V)
Load Regulation (I
O
= 1.0 mA to 20 mA)
Temperature Stability
Total Output Variation over Line, Load, and Temperature
Output Noise Voltage (f = 10 Hz to 10 kHz, T
J
= 25°C)
Long Term Stability (T
A
= 125°C for 1000 Hours)
Output Short Circuit Current
OSCILLATOR SECTION
Frequency
T
J
= 25°C
T
A
= T
low
to T
high
T
J
= 25°C (R
T
= 6.2 k, C
T
= 1.0 nF)
Frequency Change with Voltage (V
CC
= 12 V to 25 V)
Frequency Change with Temperature (T
A
= T
low
to T
high
)
Oscillator Voltage Swing (Peak−to−Peak)
Discharge Current (V
OSC
= 2.0 V)
T
J
= 25°C
T
A
= T
low
to T
high
(UC284XB, UC384XB)
T
A
= T
low
to T
high
(UC384XBV)
f
OSC
49
48
225
Df
OSC
/DV
Df
OSC
/DT
V
OSC
I
dischg
7.8
7.5
−
8.3
−
−
8.8
8.8
−
7.8
7.6
7.2
8.3
−
−
8.8
8.8
8.8
−
−
−
52
−
250
0.2
1.0
1.6
55
56
275
1.0
−
−
49
48
225
−
−
−
52
−
250
0.2
0.5
1.6
55
56
275
1.0
−
−
%
%
V
mA
kHz
V
ref
Reg
line
Reg
load
T
S
V
ref
V
n
S
I
SC
4.95
−
−
−
4.9
−
−
− 30
5.0
2.0
3.0
0.2
−
50
5.0
− 85
5.05
20
25
−
5.1
−
−
−180
4.9
−
−
−
4.82
−
−
− 30
5.0
2.0
3.0
0.2
−
50
5.0
− 85
5.1
20
25
−
5.18
−
−
−180
V
mV
mV
mV/°C
V
mV
mV
mA
Symbol
Min
Typ
Max
UC384XB, XBV
Min
Typ
Max
Unit
2. Adjust V
CC
above the Startup threshold before setting to 15 V.
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
T
high
= + 70°C for UC3844B, UC3845B
= − 25°C for UC2844B, UC2845B
= + 85°C for UC2844B, UC2845B
= − 40°C for UC3844BV, UC3845BV
= +105°C for UC3844BV, UC3845BV
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