UC3844BNG ON Semiconductor, UC3844BNG Datasheet - Page 6

• Manufacturer Part Number: UC3844BNG
• Description: IC CTLR CURRENT MODE 8-DIP
• Manufacturer: ON Semiconductor
• Type: Pulse Width Modulator Controllerr

Specifications of UC3844BNG

• Pwm Type: Current Mode
• Number Of Outputs: 1
• Frequency - Max: 275kHz
• Duty Cycle: 50%
• Voltage - Supply: 11.5 V ~ 25 V
• Buck: No
• Boost: Yes
• Flyback: Yes
• Inverting: Yes
• Doubler: No
• Divider: No
• Cuk: No
• Isolated: Yes
• Operating Temperature: 0°C ~ 70°C
• Package / Case: 8-DIP (0.300", 7.62mm)
• Frequency-max: 275kHz
• Number Of Pwm Outputs: 1
• On/off Pin: No
• Adjustable Output: No
• Topology: Boost/Flyback
• Switching Freq: 500KHz
• Operating Supply Voltage (max): 30V
• Output Current: 1000A
• Synchronous Pin: No
• Rise Time: 50ns
• Fall Time: 50ns
• Operating Temperature Classification: Commercial
• Mounting: Through Hole
• Pin Count: 8
• Package Type: PDIP
• Duty Cycle (max): 48 % (Typ)
• Output Voltage: 4.9 V to 5.1 V
• Mounting Style: Through Hole
• Switching Frequency: 500 KHz
• Operating Supply Voltage: 30 V
• Maximum Operating Temperature: 70 C
• Minimum Operating Temperature: 0 C
• Current, Input Bias: -2 μA
• Current, Output: +12 mA (Sink), -1 mA (Source)
• Current, Supply: 30 mA
• Frequency, Oscillator: 250 kHz
• Power Dissipation: 1.25 W
• Regulation, Line: 2 mV
• Regulation, Load: 3 mV
• Regulator Type: DC-DC
• Temperature, Operating, Range: 0 to +70 °C
• Time, Fall: 50 ns
• Time, Rise: 50 ns
• Voltage, Gain: 3 V/V
• Voltage, Input: -0.3 to +5.5 V
• Voltage, Noise: 50 μV
• Voltage, Output: 5 V
• Voltage, Output, High: 13.5 V
• Voltage, Output, Low: 1.6 V
• Voltage, Supply: 36 V
• Voltage, Supply, Rejection Ratio: 70 dB
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: UC3844BNGOS

PIN FUNCTION DESCRIPTION
8−Pin
- 2.0
-1.0
3.0
2.0
1.0
1
2
3
4
5
6
7
8
0
0
0
Pin
Ä Ä
2,4,6,13
14−Pin
V
CC
Ä Ä Ä Ä
Ä Ä Ä Ä
Figure 14. Output Cross Conduction
Figure 12. Output Saturation Voltage
10
12
14
11
1
3
5
7
8
9
T
A
Ä Ä Ä
Ä Ä Ä
T
= - 55°C
A
200
= 25°C
Compensation
Current Sense
I
O
versus Load Current
, OUTPUT LOAD CURRENT (mA)
Feedback
Function
Voltage
Ground
Output
Power
R
Ä Ä Ä Ä Ä
Ä Ä Ä Ä Ä
Ä Ä Ä Ä
Ä Ä Ä Ä
Ä Ä Ä Ä Ä
Ä Ä Ä Ä Ä
GND
GND
V
V
NC
T
V
CC
ref
/C
C
Source Saturation
(Load to Ground)
Sink Saturation
(Load to V
T
T
100 ns/DIV
A
= - 55°C
400
CC
This pin is the Error Amplifier output and is made available for loop compensation.
This is the inverting input of the Error Amplifier. It is normally connected to the switching power
supply output through a resistor divider.
A voltage proportional to inductor current is connected to this input. The PWM uses this
information to terminate the output switch conduction.
The Oscillator frequency and maximum Output duty cycle are programmed by connecting resistor
R
This pin is the combined control circuitry and power ground.
This output directly drives the gate of a power MOSFET. Peak currents up to 1.0 A are sourced
and sunk by this pin. The output switches at one−half the oscillator frequency.
This pin is the positive supply of the control IC.
This is the reference output. It provides charging current for capacitor C
This pin is a separate power ground return that is connected back to the power source. It is used
to reduce the effects of switching transient noise on the control circuitry.
The Output high state (V
connection, it can reduce the effects of switching transient noise on the control circuitry.
This pin is the control circuitry ground return and is connected back to the powersource ground.
No connection. These pins are not internally connected.
)
T
to V
Ä Ä Ä Ä Ä
Ä Ä Ä Ä Ä
Ä Ä Ä
ref
V
80 ms Pulsed Load
120 Hz Rate
GND
Ä Ä Ä Ä
Ä Ä Ä Ä
CC
600
and capacitor C
= 15 V
T
A
V
C
T
A
CC
= 25°C
L
= 25°C
= 15 pF
= 30 V
http://onsemi.com
800
OH
T
) is set by the voltage applied to this pin. With a separate power source
to ground. Oscillator operation to 1.0 kHz is possible.
6
90
10
%
%
25
20
15
10
5
0
Figure 15. Supply Current versus Supply Voltage
0
Description
Figure 13. Output Waveform
10
V
CC
, SUPPLY VOLTAGE (V)
50 ns/DIV
20
T
through resistor R
Ä Ä Ä Ä
Ä Ä Ä Ä
Ä Ä Ä Ä
Ä Ä Ä Ä
R
C
V
I
T
Sense
A
FB
T
T
= 25°C
= 10 k
= 3.3 nF
= 0 V
30
V
C
T
= 0 V
A
CC
L
= 25°C
= 1.0 nF
= 15 V
T
.
40