UC384XBD MOTOROLA [Motorola, Inc], UC384XBD Datasheet - Page 6

• Manufacturer Part Number: UC384XBD
• Description: HIGH PERFORMANCE CURRENT MODE CONTROLLERS
• Manufacturer: MOTOROLA [Motorola, Inc]

– 2.0
6
8–Pin
–1.0
3.0
2.0
1.0
1
2
3
4
5
6
7
8
0
0
0
Ä Ä Ä Ä
Pin
V CC
Ä Ä Ä Ä
Figure 13. Output Cross Conduction
2,4,6,13
14–Pin
Figure 11. Output Saturation Voltage
10
12
14
T A = – 55 C
11
1
3
5
7
8
9
Ä Ä Ä
T A = 25 C
200
I O , OUTPUT LOAD CURRENT (mA)
versus Load Current
Compensation
Voltage
Feedback
Current Sense
R T /C T
Gnd
Output
V CC
V ref
Power
Ground
V C
Gnd
NC
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
F
Function
Source Saturation
(Load to Ground)
Sink Saturation
(Load to V CC )
T A = – 55 C
100 ns/DIV
400
i
Ä Ä Ä Ä Ä
Ä Ä Ä Ä Ä
Ä Ä Ä Ä Ä
Ä Ä Ä
Ä Ä Ä
resistor R T .
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 T to V ref and capacitor C T to ground. Oscillator operation to 1.0 kHz is possible.
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 T through
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 OH ) is set by the voltage applied to this pin. With a separate power
source 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 power source ground.
No connection. These pins are not internally connected.
UC3844B, 45B UC2844B, 45B
V CC = 15 V
80 s Pulsed Load
120 Hz Rate
Ä Ä Ä Ä
Gnd
600
T A = 25 C
PIN FUNCTION DESCRIPTION
V CC = 30 V
C L = 15 pF
T A = 25 C
800
90%
10%
25
20
15
10
5
0
Figure 14. Supply Current versus Supply Voltage
0
D
Description
i i
MOTOROLA ANALOG IC DEVICE DATA
Figure 12. Output Waveform
10
V CC , SUPPLY VOLTAGE (V)
50 ns/DIV
20
Ä Ä Ä Ä
Ä Ä Ä Ä
Ä Ä Ä Ä
R T = 10 k
C T = 3.3 nF
V FB = 0 V
I Sense = 0 V
T A = 25 C
30
V CC = 15 V
C L = 1.0 nF
T A = 25 C
40