UC3844B, UC3845B, UC2844B, UC2845B
http://onsemi.com
2
MAXIMUM RATINGS
Rating Symbol Value Unit
Bias and Driver Voltages (Zero Series Impedance, see also Total Device spec) (Note 1) V
CC
, V
C
36 V
Total Power Supply and Zener Current (I
CC
+ I
Z
) 30 mA
Output Current, Source or Sink (Note 2) I
O
1.0 A
Output Energy (Capacitive Load per Cycle) W 5.0
mJ
Current Sense and Voltage Feedback Inputs V
in
− 0.3 to + 5.5 V
Error Amp Output Sink Current I
O
10 mA
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
P
D
R
q
JA
P
D
R
q
JA
P
D
R
q
JA
862
145
702
178
1.25
100
mW
°C/W
mW
°C/W
W
°C/W
Operating Junction Temperature T
J
+150 °C
Operating Ambient Temperature UC3844B, UC3845B
UC2844B, UC2845B
UC3844BV, UC3845BV
T
A
0 to +70
−25 to +85
−40 to +105
°C
Storage Temperature Range T
stg
− 65 to +150 °C
Stresses exceeding Maximum Ratings may damage the device. Maximum Ratings are stress ratings only. Functional operation above the
Recommended Operating Conditions is not implied. Extended exposure to stresses above the Recommended Operating Conditions may affect
device reliability.
1. The voltage is clamped by a zener diode (see page 9 Under Voltage Lockout section). Therefore this voltage may be exceeded as long as
the total power supply and zener current is not exceeded.
2. Maximum package power dissipation limits must be observed.
3. This device series contains ESD protection and exceeds the following tests: Human Body Model 4000 V per JEDEC Standard
JESD22-A114B, Machine Model Method 200 V per JEDEC Standard JESD22-A115-A
4. This device contains latch-up protection and exceeds 100 mA per JEDEC Standard JESD78
ELECTRICAL CHARACTERISTICS (V
CC
= 15 V [Note 5], 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 6], unless otherwise noted.)
UC284xB UC384xB, xBV, NCV384xBV
Characteristic Symbol Min Typ Max Min Typ Max Unit
REFERENCE SECTION
Reference Output Voltage (I
O
= 1.0 mA, T
J
= 25°C) V
ref
4.95 5.0 5.05 4.9 5.0 5.1 V
Line Regulation (V
CC
= 12 V to 25 V) Reg
line
− 2.0 20 − 2.0 20 mV
Load Regulation (I
O
= 1.0 mA to 20 mA) Reg
load
− 3.0 25 − 3.0 25 mV
Temperature Stability T
S
− 0.2 − − 0.2 − mV/°C
Total Output Variation over Line, Load, & Temperature V
ref
4.9 − 5.1 4.82 − 5.18 V
Output Noise Voltage (f = 10 Hz to 10 kHz, T
J
= 25°C) V
n
− 50 − − 50 −
mV
Long Term Stability (T
A
= 125°C for 1000 Hours) S − 5.0 − − 5.0 − mV
Output Short Circuit Current I
SC
− 30 − 85 −180 − 30 − 85 −180 mA
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)
f
OSC
49
48
225
52
−
250
55
56
275
49
48
225
52
−
250
55
56
275
kHz
Frequency Change with Voltage (V
CC
= 12 V to 25 V)
Df
OSC
/DV
− 0.2 1.0 − 0.2 1.0 %
Frequency Change w/ Temperature (T
A
= T
low
to T
high
)
Df
OSC
/DT
− 1.0 − − 0.5 − %
Oscillator Voltage Swing (Peak−to−Peak) V
OSC
− 1.6 − − 1.6 − V
5. Adjust V
CC
above the Startup threshold before setting to 15 V.
6. 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 UC384xBV, NCV384xBV =+105°C for UC3844BV, UC3845BV
= +125°C for NCV384xBV
