ST UC2842B Скачать руководство пользователя страница 3

ELECTRICAL CHARACTERISTICS ( [note 1] Unless otherwise stated, these specifications apply for
-25 < T

amb

 < 85

°

C for UC284XB; 0 < T

amb

 <  70

°

C for UC384XB; V

i

 = 15V (note 5); R

T

 = 10K; C

T

 = 3.3nF)

Symbol

Parameter

Test Conditions

UC284XB

UC384XB

Unit

Min. Typ. Max. Min. Typ. Max.

REFERENCE SECTION

V

REF

Output Voltage

T

j

 = 25

°

C  I

o

 = 1mA

4.95

5.00

5.05

4.90

5.00

5.10

V

V

REF

Line Regulation

12V 

 V

i

 

 25V

2

20

2

20

mV

V

REF

Load Regulation

 I

o

 

 20mA

3

25

3

25

mV

V

REF

/

T

Temperature Stability

(Note 2)

0.2

0.2

mV/

°

C

Total Output Variation

Line, Load, Temperature

4.9

5.1

4.82

5.18

V

e

N

Output Noise Voltage

10Hz 

 f 

 10KHz T

j

 = 25

°

C

(note 2)

50

50

µ

V

Long Term Stability

T

amb

 = 125

°

C, 1000Hrs

(note 2)

5

25

5

25

mV

I

SC

Output Short Circuit

-30

-100 -180

-30

-100 -180

mA

OSCILLATOR SECTION

f

OSC

Frequency

T

j

 = 25

°

C

T

A

 = T

low

 to T

high

T

J

 = 25°C (R

T

 = 6.2k, C

T

 = 1nF)

49
48

225

52

250

55
56

275

49
48

225

52

250

55
56

275

KHz
KHz
KHz

f

OSC

/

V

Frequency Change with Volt. V

CC

 = 12V to 25V

0.2

1

0.2

1

%

f

OSC

/

T

Frequency Change with Temp.

T

A

 = T

low

 to T

high

1

0.5

%

V

OSC

Oscillator Voltage Swing

(peak to peak)

1.6

1.6

V

I

dischg

Discharge Current (V

OSC

 =2V) T

J

 = 25°C

T

A

 = T

low

 to T

high

7.8
7.5

8.3

8.8
8.8

7.8
7.6

8.3

8.8
8.8

mA
mA

ERROR AMP SECTION

V

2

Input Voltage

V

PIN1

 = 2.5V

2.45

2.50

2.55

2.42

2.50

2.58

V

I

b

Input Bias Current

V

FB

 = 5V

-0.1

-1

-0.1

-2

µ

A

A

VOL

2V 

 V

o

 

 4V

65

90

65

90

dB

BW

Unity Gain Bandwidth

T

J

 = 25°C

0.7

1

0.7

1

MHz

PSRR

Power Supply Rejec. Ratio

12V 

 V

i

 

 25V

60

70

60

70

dB

I

o

Output Sink Current

V

PIN2

 = 2.7V   V

PIN1

 = 1.1V

2

12

2

12

mA

I

o

Output Source Current

V

PIN2 

= 2.3V  V

PIN1

 = 5V

-0.5

-1

-0.5

-1

mA

V

OUT

 High

V

PIN2

 = 2.3V;

R

L

 = 15K

 to Ground

5

6.2

5

6.2

V

V

OUT

 Low

V

PIN2

 = 2.7V;

R

L

 = 15K

 to Pin 8

0.8

1.1

0.8

1.1

V

CURRENT SENSE SECTION

G

V

Gain

(note 3 & 4)

2.85

3

3.15

2.85

3

3.15

V/V

V

3

Maximum Input Signal

V

PIN1

 = 5V (note 3)

0.9

1

1.1

0.9

1

1.1

V

SVR

Supply Voltage Rejection

12 

 V

i

 

 25V (note 3)

70

70

dB

I

b

Input Bias Current

-2

-10

-2

-10

µ

A

Delay to Output

150

300

150

300

ns

THERMAL DATA

Symbol

Description

Minidip

SO8

Unit

R

th j-amb

Thermal Resistance Junction-ambient.                                     max.

100

150

°

C/W

UC2842B/3B/4B/5B - UC3842B/3B/4B/5B

3/15

Содержание UC2842B

Страница 1: ...amp input logic to insure latched operation a PWM comparatorwhich also providescurrent limit control and a totem pole output stage designed to source or sink high peak current The output stage suitabl...

Страница 2: ...to 150 C TL Lead Temperature soldering 10s 300 C PIN FUNCTIONS No Function Description 1 COMP This pin is the Error Amplifier output and is made available for loop compensation 2 VFB This is the inve...

Страница 3: ...1 0 2 1 fOSC T Frequency Change with Temp TA Tlow to Thigh 1 0 5 VOSC Oscillator Voltage Swing peak to peak 1 6 1 6 V Idischg Discharge Current VOSC 2V TJ 25 C TA Tlow to Thigh 7 8 7 5 8 3 8 8 8 8 7 8...

Страница 4: ...High Level ISOURCE 20mA 13 13 5 13 13 5 V ISOURCE 200mA 12 13 5 12 13 5 V VOLS UVLO Saturation VCC 6V ISINK 1mA 0 1 1 1 0 1 1 1 V tr Rise Time Tj 25 C CL 1nF 2 50 150 50 150 ns tf Fall Time Tj 25 C CL...

Страница 5: ...gle point ground The transistor and 5K potentiometerareusedtosampletheoscillator waveform and apply an adjustable ramp to pin 3 10K 20K 30K 50K 100K 200K 300K 500K fOSC KHz 1 2 5 10 20 50 D95IN333 CT...

Страница 6: ...Vi 15V VO 2V to 4V RL 100K TA 25 C Gain Phase Figure 6 Error Amp Open Loop Gain and Phase vs Frequency 0 2 4 6 VO V 0 0 0 2 0 4 0 6 0 8 1 0 Vth V D95IN338 Vi 15V TA 40 C TA 125 C TA 25 C Figure 7 Curr...

Страница 7: ...43 45 UCX842 44 RT 10K CT 3 3nF VFB 0V ISense 0V TA 25 C D95IN342 Figure 11 Supply Current vs Supply Voltage Figure 12 Output Waveform Figure 13 Output Cross Conduction 5V REG OSCILLATOR PWM CLOCK 8 4...

Страница 8: ...MAND TO REST OF IC 7 0 5mA 17mA ICC VCC VOFF VON D95IN346 Figure 17 Current Sense Circuit ERROR AMPL 2R R 1V CURRENT SENSE COMPARATOR 1 CURRENT SENSE COMP C RS R 3 5 GND IS D95IN347 Peak current is is...

Страница 9: ...PE CT RT VREG 8 RT CT ISENSE 4 3 5 GND D95IN348 Figure 19 Isolated MOSFET Drive and Current Transformer Sensing 7 6 COMP LATCH ISOLATION BOUNDARY D95IN349 5 0Vref VCC Q S R 3 R RS NS C Vin Q1 NP VGS W...

Страница 10: ...51 EA Ri 1mA Rd R 2R 5 Cf Rf 1 2 From VO 2 5V EA RP 1mA Rd R 2R 5 Cf Rf 1 2 From VO 2 5V Error Amp compensation circuit for stabilizing any current mode topology except for boost and flyback converter...

Страница 11: ...3 External Duty Cycle Clamp and Multi Unit Synchronization D95IN352 EA R 2R 5 RT 1 2 EXTERNAL SYNC INPUT The diode clamp is required if the Sync amplitude is large enough to cause the bottom side of C...

Страница 12: ...art Circuit D95IN355 R BIAS OSC C R EA R 2R R S Q 8 4 2 1 5 1mA 1V 5Vref R2 R1 VClamp Comp Latch 7 RS VCC Q1 Vin 7 6 5 BC109 VCLAMP R1 R1 R2 where 0 VCLAMP 1V Ipk max VCLAMP RS Figure 25 Soft Start an...

Страница 13: ...010 C 0 25 0 5 0 010 0 020 c1 45 typ D 1 4 8 5 0 0 189 0 197 E 5 8 6 2 0 228 0 244 e 1 27 0 050 e3 3 81 0 150 F 1 3 8 4 0 0 15 0 157 L 0 4 1 27 0 016 0 050 M 0 6 0 024 S 8 max 1 D and F do not includ...

Страница 14: ...1 65 0 045 0 065 b 0 356 0 55 0 014 0 022 b1 0 204 0 304 0 008 0 012 D 10 92 0 430 E 7 95 9 75 0 313 0 384 e 2 54 0 100 e3 7 62 0 300 e4 7 62 0 300 F 6 6 0 260 I 5 08 0 200 L 3 18 3 81 0 125 0 150 Z 1...

Страница 15: ...ice This publication supersedes and replaces all information previously supplied STMi croelectronics products are not authorized for use as critical components in life support devices or systems witho...

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