CURRENT MODE PWM CONTROLLER

LM3842A/3A/4A/5A

ELECTRICAL CHARACTERISTIC

Characteristic

Symbol

Test Condition

Min

Typ

Max

Unit

REFERENCE SECTION

Reference Output Voltage

4.90

5.00

5.10

V

Line Regulation

Vo

12V ≤ Vcc ≤ 25V

2

20

mV

Load Regulation

Vo

1mA ≤ Io ≤ 20mA

3

2.5

mV

Output Short Circuit Current

Isc

-85

-180

mA

OSCILLATOR SECTION

Normal Frequency

47

52

57

kHz

Voltage Stability

Sv

12V ≤ Vcc ≤ 25V

0.2

1

%

Amplitude

Vosc

1.6

Vp-p

ERROR AMPLIFIER SECTION

Input B

Current

I

-0.1

-2

μA

Feedback Input Voltage

Vo=2.5V

2.42

2.50

2.58

V

Open Loop Voltage Gain

2V≤ Vo ≤ 4V

65

90

dB

Power Supplier Rejection Ratio

12V ≤ Vcc ≤ 25V

60

70

dB

Output Sink Current

27

mA

Output source Current

V

= 2.3V, Vo=5V

-0.5

-1.0

mA

Output Voltage High

56

V

Output Voltage Low

0.8

1.1

V

CURRENT SENSE SECTION

Input Voltage Gain

Av

(Note 2 & 3)

2.85

3

3.15

V/V

Maximum Input Signal

Vo=5V (Note 2)

0.9

1

1.1

V

Power Supply Rejection Ratio

12V ≤ Vcc ≤ 25V

70

dB

Input Bias Current

I

-2

-1.0

μA

OUTPUT SECTION

Output Voltage Low

0.1

0.4

V

s

= 20mA

1.5

2.2

V

Output Voltage High

13

13.5

V

s

= 20mA

12

13.0

V

Rise Time

T

45

150

nS

Fail Time

T

35

150

nS

UNDERVOLTAGE LOCKOUT SECTION

Start-up Threshold

3842A / 3844A

14.5

16

17.5

V

3843A / 3845A

7.8

8.4

9

V

Minimum Operating Voltage

3842A / 3844A

8.5

10

11.5

V

(After Turn-On )

3843A / 3845A

7.0

7.6

8.2

V

TOTAL STANDBY CURRENT

Start-up Current

Vcc=14V

0.17

0.3

mA

Operating Supply Current

C

13

mA

17

Zener Voltage

V

Icc = 25mA

30

38

V

Note: 1. Adjust Vcc above the start threshould before setting at 15V.

3. Comparator Gain defined as:

HTC

2

ΔV Output Compensation(pin FB)

ΔV Current Sanseinput(pin CS)

A

V

=

;