Unitrode UC3524ADW, UC3524AQ, UC3524AN, UC3524AL, UC3524AJ Datasheet

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Unitrode UC3524ADW, UC3524AQ, UC3524AN, UC3524AL, UC3524AJ Datasheet

UC1524A

UC2524A

UC3524A

Advanced Regulating Pulse Width Modulators

FEATURES

Fully Interchangeable with Standard UC1524 Family

Precision Reference Internally Trimmed to ±1%

High-Performance Current Limit Function

Under-Voltage Lockout with Hysteretic Turn-on

Start-Up Supply Current Less Than 4mA

Output Current to 200mA

60V Output Capability

Wide Common-Mode Input Range for both Error and Current Limit Amplifiers

PWM Latch Insures Single Pulse per Period

Double Pulse Suppression Logic

200ns Shutdown through PWM Latch

Guaranteed Frequency Accuracy

Thermal Shutdown Protection

BLOCK DIAGRAM

DESCRIPTION

The UC1524A family of regulating PWM ICs has been designed to retain the same highly versatile architecture of the industry standard UC1524 (SG1524) while offering substantial improvements to many of its limitations. The UC1524A is pin compatible with “non-A” models and in most existing applications can be directly interchanged with no effect on power supply performance. Using the UC1524A, however, frees the designer from many concerns which typically had required additional circuitry to solve.

The UC1524A includes a precise 5V reference trimmed to ±1% accuracy, eliminating the need for potentiometer adjustments; an error amplifier with an input range which includes 5V, eliminating the need for a reference divider; a current sense amplifier useful in either the ground or power supply output lines; and a pair of 60V, 200mA uncommitted transistor switches which greatly enhance output versatility.

An additional feature of the UC1524A is an under-voltage lockout circuit which disables all the internal circuitry, except the reference, until the input voltage has risen to 8V. This holds standby current low until turn-on, greatly simplifying the design of low power, off-line supplies. The turn-on circuit has approximately 600mV of hysteresis for jitter-free activation.

Other product enhancements included in the UC1524A’s design include a PWM latch which insures freedom from multiple pulsing within a period, even in noisy environments, logic to eliminate double pulsing on a single output, a 200ns external shutdown capability, and automatic thermal protection from excessive chip temperature. The oscillator circuit of the UC1524A is usable beyond 500kHz and is now easier to synchronize with an external clock pulse.

The UC1524A is packaged in a hermetic 16-pin DIP and is rated for operation from -55°C to +125°C. The UC2524A and 3524A are available in either ceramic or plastic packages and are rated for operation from -25°C to +85°C and 0°C to 70°C, respectively. Surface mount devices are also available.

VIN

15

 

 

 

 

 

 

 

 

 

 

 

OSC

3

RT

 

 

 

 

 

6

CT

 

 

7

COMP

 

 

 

 

 

 

 

9

INV. INPUT

 

 

 

 

1

N.I. INPUT

 

 

 

 

 

2

CL (+) SENSE

 

 

 

 

4

CL (–) SENSE

 

 

 

 

5

 

 

 

 

 

 

 

+5V

 

 

 

 

REFERENCE

 

U.V.

POWER TO

REGULATOR

 

 

 

 

INTERNAL

 

 

SENSE

 

 

 

CIRCUITRY

 

 

 

FLIP

 

 

 

 

 

 

 

 

FLOP

 

 

 

 

T

OSC

CLOCK

 

 

 

 

 

 

 

 

RAMP

COMP

R

 

 

 

S

PWM

 

 

 

S

 

 

VIN

LATCH

 

 

 

 

 

 

E/A

 

 

1k

200mV

VIN

6V

10k

5.5V

+

 

 

 

 

 

 

C/L

 

 

 

16 VREF

12 CA

11 EA

13CB

14EB

10 SHUTDOWN

8 GND

UDG-99178

SLUS181A - NOVEMBER 1999

ABSOLUTE MAXIMUM RATINGS

Supply Voltage (VIN) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40V Collector Supply Voltage (VC) . . . . . . . . . . . . . . . . . . . . . . . 60V Output Current (each Output). . . . . . . . . . . . . . . . . . . . . 200mA Maximum Forced Voltage (Pin 9, 10) . . . . . . . . . . . . . -3 to +5V Maximum Forced Current (Pin 9, 10) . . . . . . . . . . . . . . . ±10mA Reference Output Current . . . . . . . . . . . . . . . . . . . . . . . . 50mA Oscillator Charging Current . . . . . . . . . . . . . . . . . . . . . . . . 5mA Power Dissipation at TA = +25°C. . . . . . . . . . . . . . . . . 1000mW Power Dissipation at TC = +25°C . . . . . . . . . . . . . . . . 2000mW Operating Temperature Range . . . . . . . . . . . . -55°C to +125°C Storage Temperature Range. . . . . . . . . . . . . . -65°C to +150°C Lead Temperature, (Soldering, 10 seconds) . . . . . . . . . +300°C

Note: Consult packaging section of Databook for thermal limitations and considerations of package.

DIL-16, SOIC-16 (TOP VIEW)

J or N Package, DW Package

UC1524A

UC2524A

UC3524A

CONNECTION DIAGRAMS

PLCC-20, LCC-20 (TOP VIEW)

Q or L Package

PACKAGE PIN FUNCTION

FUNCTION

PIN

N/C

1

Inv. Input

2

Non-Inv. Input

3

OSC/SYNC

4

C.L. (+) sense

5

N/C

6

C.L. (-) sense

7

RT

8

CT

9

Ground

10

N/C

11

Compensation

12

Shutdown

13

Emitter A

14

Collector A

15

N/C

16

Collector B

17

Emitter B

18

+VIN

19

+5V VREF

20

ELECTRICAL CHARACTERISTICS: Unless otherwise stated, these specifications apply for TA = -55°C to +125°C for the UC1524A, -25° to +85°C for the UC2524A, and 0°C to + 70°C for the UC3524A; VIN

= VC = 20V, TA = TJ.

PARAMETER

TEST CONDITIONS

UC1524A / UC2524A

 

UC3524A

 

UNITS

MIN

TYP

MAX

MIN

 

TYP

 

MAX

 

 

 

 

 

 

Turn-on Characteristics

 

 

 

 

 

 

 

 

 

 

Input Voltage

Operating Range after Turn-on

8

 

40

8

 

 

 

40

V

Turn-on Threshold

 

6.5

7.5

8.5

6.5

 

7.5

 

8.5

V

Turn-on Current

VIN = 6V

 

2.5

4

 

 

2.5

 

4

mA

Operating Current

VIN = 8 to 40V

 

5

10

 

 

5

 

10

mA

Turn-on Hysteresis*

 

 

0.5

 

 

 

0.5

 

 

V

Reference Section

 

 

 

 

 

 

 

 

 

 

Output Voltage

TJ = 25°C

4.95

5.00

5.05

4.90

 

5.00

 

5.10

V

 

Over Operating Range

4.9

 

5.1

4.85

 

 

 

5.15

V

Line Regulation

VIN = 10 to 40V

 

10

20

 

 

10

 

30

mV

Load Regulation

IL = 0 to 20 mA

 

20

25

 

 

20

 

35

mV

Temperature Stability*

Over Operating Range*

 

20

25

 

 

20

 

35

mV

Short Circuit Current

VREF = 0, 25°C TJ 125°C

 

80

100

 

 

80

 

100

mA

Output Noise Voltage*

10Hz f 10kHz, TJ =25°C

 

40

 

 

 

40

 

 

Vrms

Long Term Stability*

TJ =125°C, 1000 Hrs.

 

20

50

 

 

20

 

50

mV

* These parameters are guaranteed by design but not 100% tested in production.

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UC1524A

UC2524A

UC3524A

ELECTRICAL CHARACTERISTICS: Unless otherwise stated, these specifications apply for TA = -55°C to +125°C for the UC1524A, -25° to +85°C for the UC2524A, and 0°C to + 70°C for the UC3524A; VIN = VC = 20V, TA = TJ.

PARAMETER

TEST CONDITIONS

UC1524A / UC2524A

 

UC3524A

 

UNITS

MIN

TYP

MAX

MIN

 

TYP

 

MAX

 

 

 

 

 

 

Oscillator Section (Unless otherwise specified, RT = 2700Ω, CT = 0.01 mfd)

 

 

 

 

 

 

 

 

Initial Accuracy

TJ = 25°C

41

43

45

39

 

43

 

47

kHz

 

Over Operating Range

40.2

 

45.9

38.2

 

 

 

47.9

kHz

Temperature Stability*

Over Operating Temperature Range

 

1

2

 

 

1

 

2

%

Minimum Frequency

RT = 150kΩ, CT = 0.1mfd

 

 

140

 

 

 

 

120

Hz

Maximum Frequency

RT = 2.0kΩ, CT = 470pF

500

 

 

500

 

 

 

 

kHz

Output Amplitude*

 

3

3.5

 

3

 

3.5

 

 

V

Output Pulse Width*

 

0.29

0.5

1.0

0.3

 

0.5

 

1.0

µs

Ramp Peak

 

3.3

3.5

3.7

3.3

 

3.5

 

3.7

V

Ramp Valley

TJ = 25°C

0.7

0.8

0.9

0.7

 

0.8

 

0.9

V

Ramp Valley T.C.

 

 

-1.0

 

 

 

-1.0

 

 

mV/°C

Error Amplifier Section (Unless otherwise specified, VCM = 2.5V)

 

 

 

 

 

 

 

 

 

Input Offset Voltage

 

 

0.5

5

 

 

2

 

10

mV

Input Bias Current

 

 

1

5

 

 

1

 

10

µA

Input Offset Current

 

 

.05

1

 

 

0.5

 

1

µA

Common Mode Rejection Ratio

VCM = 1.5 to 5.5V

70

80

 

70

 

80

 

 

dB

Power Supply Rejection Ratio

VIN = 10 to 40V

70

80

 

70

 

80

 

 

dB

Output Swing (Note 1)

 

5.0

 

0.5

5.0

 

 

 

0.5

V

Open Loop Voltage Gain

∆VO= 1 to 4V, RL ≥ 10MΩ

72

80

 

64

 

80

 

 

dB

Gain-Bandwidth*

TJ = 25°C, AV = 0dB

1

3

 

1

 

3

 

 

MHz

DC Transconductance*§

TJ = 25°C, 30kΩ ≤ RL ≤ 1MΩ

1.7

2.3

 

1.7

 

2.3

 

 

mS

P.W.M. Comparator (RT = 2kΩ, CT = 0.01mfd)

 

 

 

 

 

 

 

 

 

Minimum Duty Cycle

VCOMP = 0.5V

 

 

0

 

 

 

 

0

%

Maximum Duty Cycle

VCOMP = 3.8V

45

 

 

45

 

 

 

 

%

Current Limit Amplifier (Unless otherwise specified, Pin 5 = 0V)

 

 

 

 

 

 

 

 

 

Input Offset Voltage

TJ = 25°C, E/A Set for Maximum

190

200

210

180

 

200

 

220

mV

 

Output

 

 

 

 

 

 

 

 

 

 

Over Operating Temperature Range

180

 

220

170

 

 

 

230

mV

Input Bias Current

 

 

-1

-10

 

 

-1

 

-10

µA

Common Mode Rejection Ratio

V(pin 5) = -0.3V to + 5.5V

50

60

 

50

 

60

 

 

dB

Power Supply Rejection Ratio

VIN = 10 to 40V

50

60

 

50

 

60

 

 

dB

Output Swing (Note 1)

Minimum Total Range

5.0

 

0.5

5.0

 

 

 

0.5

V

Open-Loop Voltage Gain

∆VO = 1 to 4V, RL ≥ 10MΩ

70

80

 

70

 

80

 

 

dB

Delay Time*

Pin 4 to Pin 9, ∆VIN = 300mV

 

300

 

 

 

300

 

 

ns

Output Section (Each Output)

 

 

 

 

 

 

 

 

 

 

Collector Emitter Voltage

IC = 100µA

60

80

 

60

 

80

 

 

V

Collector Leakage Current

VCE = 50V

 

.1

20

 

 

.1

 

20

µA

* These parameters are guaranteed by design but not 100% tested in production.

§DC transconductance (gM) relates to DC open-loop voltage gain according to the following equation: AV = gMRL where RL is the resistance from pin 9 to the common mode voltage.

The minimum gM specification is used to calculate minimum AV when the error amplifier output is loaded. Note 1: Min Limit applies to output high level, max limit applies to output low level.

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