Details

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BUY UC3844BD1013TR https://www.utsource.net/itm/p/12543102.html

Parameter	Symbol	Conditions	Min	Typ	Max	Unit
Supply Voltage	Vcc	Operating	10	-	40	V
Startup Current	Istrt		0.7	-	1.3	mA
Quiescent Current	Iq	Vcc = 16V	2.5	-	4.0	mA
Error Amplifier Transconductance	Gm		1.5	-	2.5	mS
Frequency Compensation Pin Capacitance	Cc	fsw = 100kHz	100	-	1000	pF
Slope Compensation	Vsc		0.8	-	1.2	V/us
Oscillator Frequency	fosc	RT = 20kΩ, CT = 1nF	100	-	500	kHz
Reference Voltage	Vref		4.95	-	5.05	V
Maximum Duty Cycle	Dmax		0.5	-	0.95
Under-Voltage Lockout	UVLO	Release	10	-	12	V
Overcurrent Protection Threshold	Isense		0.35	-	0.65	A

Instructions for UC3844BD1013TR:

1. Power Supply Connection:

   • Connect the supply voltage (Vcc) between 10V and 40V to pin 7.
   • Ensure a bypass capacitor is connected from pin 7 to ground for stable operation.

2. Startup and Quiescent Current:

   • The startup current should be within 0.7mA to 1.3mA.
   • The quiescent current at Vcc = 16V should be between 2.5mA and 4.0mA.

3. Error Amplifier Configuration:

   • Set up the error amplifier with a transconductance (Gm) between 1.5mS and 2.5mS.
   • Use an appropriate frequency compensation capacitor on pin 4.

4. Frequency Compensation:

   • Select a capacitance value for the frequency compensation pin (pin 4) between 100pF and 1000pF depending on the switching frequency.

5. Slope Compensation:

   • Ensure slope compensation is set to a rate between 0.8V/us and 1.2V/us to prevent sub-harmonic oscillations.

6. Oscillator Setup:

   • Configure the oscillator frequency using external resistors (RT) and capacitors (CT). For example, use RT = 20kΩ and CT = 1nF for frequencies between 100kHz and 500kHz.

7. Reference Voltage:

   • The internal reference voltage is maintained between 4.95V and 5.05V.

8. Duty Cycle Control:

   • Limit the maximum duty cycle to between 50% and 95% to ensure proper operation and avoid saturation.

9. Under-Voltage Lockout (UVLO):

   • The device will enter UVLO mode when Vcc drops below 10V and will restart once it rises above 12V.

10. Overcurrent Protection:

    • Set the overcurrent protection threshold between 0.35A and 0.65A by configuring the sense resistor appropriately.

(For reference only)