MOTOROLA MC34025, MC33025 Technical data

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The MC34025 series are high speed, fixed frequency, double–ended pulse width modulator controllers optimized for high frequency operation. They are specifically designed for Off–Line and DC–to–DC converter applications offering the designer a cost effective solution with minimal external components. These integrated circuits feature an oscillator, a temperature compensated reference, a wide bandwidth error amplifier, a high speed current sensing comparator, steering flip–flop, and dual high current totem pole outputs ideally suited for driving power MOSFETs.

Also included are protective features consisting of input and reference undervoltage lockouts each with hysteresis, cycle–by–cycle current limiting, and a latch for single pulse metering.

The flexibility of this series allows it to be easily configured for either current mode or voltage mode control.

• 50 ns Propagation Delay to Outputs

• Dual High Current Totem Pole Outputs

• Wide Bandwidth Error Amplifier

• Fully–Latched Logic with Double Pulse Suppression

• Latching PWM for Cycle–By–Cycle Current Limiting

• Soft–Start Control with Latched Overcurrent Reset

• Input Undervoltage Lockout with Hysteresis

• Low Start–Up Current (500 µA Typ)

• Internally Trimmed Reference with Undervoltage Lockout

• 90% Maximum Duty Cycle (Externally Adjustable)

• Precision Trimmed Oscillator

• Voltage or Current Mode Operation to 1.0 MHz

• Functionally Similar to the UC3825

Simplified Application

V

ref

Clock

R

T

C

T

Ramp

Error Amp

Output

Noninverting

Input

Inverting

Input

Soft–Start

16

4 5

Oscillator

6 7

3

2

1 8

Error Amp

Soft–Star

t

This device contains 227 active transistors.

5.1V

Reference

UVLO

Latching

PWM and

Steering Flip Flop

Ground

10

15

V

CC

13

V

C

14

Output B

11

Output A Power Ground

12

9

Current Limit/ Shutdown

Order this document by MC34025/D

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16

1

P SUFFIX

PLASTIC PACKAGE

CASE 648

16

1

DW SUFFIX

PLASTIC PACKAGE

CASE 751G

(SO–16L)

PIN CONNECTIONS

Error Amp

Inverting Input

Error Amp

Noninverting Input

Error Amp Output

Soft–Start

ORDERING INFORMATION

Device

MC33025DW MC33025P Plastic DIP MC34025DW SO–16L MC34025P

1 2 3 4

Clock

5

R

T

6

C

T

7

Ramp

8

(Top View)

Operating

Temperature Range

TA = –40° to +105°C

TA = 0° to +70°C

16

V

ref

15

V

CC

14

Output B

13

V

C

12

Power Ground

11

Output A

10

Ground Current Limit/

9

Shutdown

Plastic DIP

Package

SO–16L

MOTOROLA ANALOG IC DEVICE DATA

 Motorola, Inc. 1996 Rev 1

1

MC34025 MC33025

MAXIMUM RATINGS

Rating Symbol Value Unit

Power Supply Voltage V Output Driver Supply Voltage V Output Current, Source or Sink (Note 1)

DC

Pulsed (0.5 µs) Current Sense, Soft–Start, Ramp, and Error Amp Inputs V Error Amp Output and Soft–Start Sink Current I Clock and RT Output Current I Power Dissipation and Thermal Characteristics

SO–16 Package (Case 751G)

Maximum Power Dissipation @ TA = +25°C Thermal Resistance, Junction–to–Air

DIP Package (Case 648)

Maximum Power Dissipation @ TA = +25°C

Thermal Resistance, Junction–to–Air Operating Junction Temperature T Operating Ambient Temperature (Note 2)

MC34025 MC33025

Storage Temperature Range T

R

CC

C

I

O

in

O

CO

P

D

θJA

P

D

θJA

J

T

A

stg

30 V 20 V

0.5

2.0

–0.3 to +7.0 V

10 mA

5.0 mA

862 145

1.25 100

mW

°C/W

W

°C/W

+150 °C

°C

0 to +70

–40 to +105 –55 to +150 °C

A

ELECTRICAL CHARACTERISTICS (V

= 15 V, RT = 3.65 kΩ, CT = 1.0 nF, for typical values TA = +25°C, for min/max values TA is

CC

the operating ambient temperature range that applies [Note 2], unless otherwise noted.)

Characteristic

Symbol Min Typ Max Unit

REFERENCE SECTION

Reference Output Voltage (IO = 1.0 mA, TJ = +25°C) V Line Regulation (VCC = 10 V to 30 V) Reg Load Regulation (IO = 1.0 mA to 10 mA) Reg T emperature Stability T Total Output Variation over Line, Load, and Temperature V Output Noise Voltage (f = 10 Hz to 10 kHz, TJ = +25°C) V

ref

line load S

ref

n

5.05 5.1 5.15 V – 2.0 15 mV – 2.0 15 mV – 0.2 – mV/°C

4.95 – 5.25 V – 50 – µV

Long Term Stability (TA = +125°C for 1000 Hours) S – 5.0 – mV Output Short Circuit Current I

SC

–30 –65 –100 mA

OSCILLATOR SECTION

Frequency

TJ = +25°C Line (VCC = 10 V to 30 V) and Temperature (TA = T

low

to T

high

) Frequency Change with Voltage (VCC = 10 V to 30 V) ∆f Frequency Change with Temperature (TA = T

low

to T

) ∆f

high

Sawtooth Peak Voltage V Sawtooth Valley Voltage V

f

osc

/∆V – 0.2 1.0 %

osc

/∆T – 2.0 – %

osc

P V

380 370

400 400

420 430

2.6 2.8 3.0 V

0.7 1.0 1.25 V

Clock Output Voltage

High State Low State

NOTES: 1. Maximum package power dissipation limits must be observed.

2.Low duty cycle pulse techniques are used during test to maintain junction temperature as close to ambient as possible. T

= 0°C for MC34025 T

low

T

= – 40°C for MC33025 T

low

= +70°C for MC34025

high

= +105°C for MC33025

high

V

OH

V

OL

3.9 –

2.3

4.5

–

2.9

kHz

V

2

MOTOROLA ANALOG IC DEVICE DATA

MC34025 MC33025

p

th

ELECTRICAL CHARACTERISTICS (V

= 15 V, RT = 3.65 kΩ, CT = 1.0 nF, for typical values TA = +25°C, for min/max values

CC

TA is the operating ambient temperature range that applies [Note 2], unless otherwise noted.)

Characteristic

Symbol Min Typ Max Unit

ERROR AMPLIFIER SECTION

Input Offset Voltage V Input Bias Current I Input Offset Current I Open–Loop Voltage Gain (VO = 1.0 V to 4.0 V) A

IO IB

IO

VOL

– – 15 mV – 0.6 3.0 µA – 0.1 1.0 µA

60 95 – dB Gain Bandwidth Product (TJ = +25°C) GBW 4.0 8.3 – MHz Common Mode Rejection Ratio (VCM = 1.5 V to 5.5 V) CMRR 75 95 – dB Power Supply Rejection Ratio (VCC = 10 V to 30 V) PSRR 85 110 – dB Output Current, Source (VO = 4.0 V)

Output Current, Sink (VO = 1.0 V)

Output Voltage Swing, High State (IO = – 0.5 mA)

Output Voltage Swing, Low State (IO = 1.0 mA)

I

Source

I

Sink

V

OH

V

OL

0.5

1.0

4.5

3.0

3.6

4.75

0

0.4

– –

5.0

1.0

Slew Rate SR 6.0 12 – V/µs

PWM COMPARATOR SECTION

Ramp Input Bias Current I Duty Cycle, Maximum

Duty Cycle, Minimum

DC

DC Zero Duty Cycle Threshold Voltage Pin 3(4) (Pin 7(9) = 0 V) V Propagation Delay (Ramp Input to Output, TJ = +25°C) t

PLH(in/out)

IB

(max)

(min)

th

– –0.5 –5.0 µA

80

–

90

–

0

–

1.1 1.25 1.4 V – 60 100 ns

SIFT–START SECTION

Charge Current (V

Soft–Start

Discharge Current (V

= 0.5 V) I

Soft–Start

= 1.5 V) I

chg

dischg

3.0 9.0 20 µA

1.0 4.0 – mA

CURRENT SENSE SECTION

Input Bias Current (Pin 9(12) = 0 V to 4.0 V) I Current Limit Comparator Threshold

Shutdown Comparator Threshold

Propagation Delay (Current Limit/Shutdown to Output, TJ = +25°C) t

PLH(in/out)

IB

V

th

V

th

– – 15 µA

0.9

1.0

1.10

1.25 1.40 1.55 – 50 80 ns

OUTPUT SECTION

Output Voltage

Low State (I

High State (I

Output Voltage with UVLO Activated (VCC = 6.0 V, I Output Leakage Current (VC = 20 V) I Output Voltage Rise T ime (CL = 1.0 nF, TJ = +25°C) t Output Voltage Fall T ime (CL = 1.0 nF, TJ = +25°C) t

Sink

(I

Sink Source

(I

Source

= 20 mA) = 200 mA)

= 0.5 mA) V

Sink

V

OL

V

OH

OL(UVLO)

L

r f

– –

13 12

0.25

1.2

13.5 13

0.4

2.2 – –

– 0.25 1.0 V – 100 500 µA – 30 60 ns – 30 60 ns

UNDERVOLTAGE LOCKOUT SECTION

Start–Up Threshold (VCC Increasing) V UVLO Hysteresis Voltage (VCC Decreasing After Turn–On) V

th(on)

H

8.8 9.2 9.6 V

0.4 0.8 1.2 V

TOTAL DEVICE

Power Supply Current

Start–Up (VCC = 8.0 V) Operating

NOTES: 1. Maximum package power dissipation limits must be observed.

2.Low duty cycle pulse techniques are used during test to maintain junction temperature as close to ambient as possible. T

= 0°C for MC34025 T

low

= – 40°C for MC33025 T

T

low

= +70°C for MC34025

high

= +105°C for MC33025

high

I

CC

– –

0.5 25

1.2 35

mA

V

%

V

mA

MOTOROLA ANALOG IC DEVICE DATA

3

Figure 1. Timing Resistor versus

100 k

1

3

Ω

CT=

1. 100 nF

10 k

2. 47 nF

3. 22 nF

4. 10 nF

5. 4.7 nF

, TIMING RESISTOR ( )

6. 2.2 nF

T

R

7. 1.0 nF

1.0 k

8. 470 pF

9. 220 pF

470

100 1000 10

2

Oscillator Frequency

5

7

9

4

6

8

4

f

, OSCILLAT OR FREQUENCY (Hz)

osc

10

5

MC34025 MC33025

VCC = 15 V

TA = +25

6

10

°

C

7

10

1200

1000

, OSCILLAT OR FREQUENCY (kHz)f

osc

Figure 2. Oscillator Frequency versus T emperature

1.0 MHz

800

600

400

200

VCC = 15 V

400 kHz

50 kHz

0

– 55 – 25 0 25 75 100 125

TA, AMBIENT TEMPERATURE (°C)

50

RT = 1.2 k

CT = 1.0 nF

RT = 3.6 k CT = 1.0 nF

RT = 36 k CT = 1.0 nF

Figure 3. Error Amp Open Loop Gain and

Phase versus Frequency

120 100

80 60

40 20

, OPEN LOOP VOL TAGE GAIN (dB)

0

VOL

A

–20

10 100 1.0 k 10 k 100 k 1.0 M 10 M

Phase

Gain

f, FREQUENCY (Hz)

Figure 5. Error Amp Small Signal

Transient Response

2.55 V

0

45

90

θ

135

1.3

1.28

C)

°

1.26

1.24

, ZERO DUTY CYCLE (V)

, EXCESS PHASE (

th

1.22

V

1.2

3.0 V

Figure 4. PWM Comparator Zero Duty Cycle

Threshold V oltage versus Temperature

VCC = 15 V Pin 7(9) = 0 V

–55 –25 0 25 50 75 100

TA, AMBIENT TEMPERATURE (

°

C)

Figure 6. Error Amp Large Signal

Transient Response

125

2.5 V

2.45 V

4

2.5 V

2.0 V

0.1 µs/DIV 0.1 µs/DIV

MOTOROLA ANALOG IC DEVICE DATA

MC34025 MC33025

Figure 7. Reference V oltage Change

0

–5.0

VCC = 15 V

–10

–15

–20

–25

, REFERENCE VOLTAGE CHANGE (mV)

ref

V

–30

0

10 20 30 40 50

Figure 9. Reference Line Regulation Figure 10. Reference Load Regulation

versus Source Current

TA = –55°C

TA = +125°C

I

, SOURCE CURRENT (mA)

Source

TA = +25°C

65.6

65.2

64.8

64.4

, REFERENCE SHORT CIRCUIT CURRENT (mA)

SC

I

Figure 8. Reference Short Circuit Current

versus T emperature

66

VCC = 15 V

64

–55

–25 0 25 50 75 100 125

TA, AMBIENT TEMPERATURE (

°

C)

2.0 mV/DIV

V

LINE REGULA TION 10 V – 24 V

ref

2.0 ms/DIV

Figure 11. Current Limit Comparator Threshold

Change versus T emperature

4.0

2.0 0

–2.0 –4.0 –6.0 –8.0

–10 –12

(CL), CURRENT LIMIT THRESHOLD CHANGE (mV)V

th

∆

TA, AMBIENT TEMPERATURE (°C)

2.0 mV/DIV

V

ref

Figure 12. Shutdown Comparator Threshold

V oltage versus Temperature

1.50

VCC = 15 V

1.46

1.42

1.38

1.34

, SHUTDOWN THRESHOLD VOLTAGE (V)V

th

1.30

100 0

–55 –25 25 50 75 100 125–50 – 25 0 25 50 75 125

TA, AMBIENT TEMPERATURE (

LINE REGULA TION 1.0 mA – 10 mA

2.0 ms/DIV

°

C)

MOTOROLA ANALOG IC DEVICE DATA

5

MC34025 MC33025

Figure 13. Soft–Start Charge Current

versus T emperature

A)

10

µ

, SOFT-ST ART CHARGE CURRENT ( I

chg

VCC = 15 V

9.5

9.0

8.5

8.0

7.5

7.0 –55 –25 0 25 50 75 100 125

TA, AMBIENT TEMPERATURE (

°

C)

, OUTPUT SA TURATION VOLTAGE (V)

sat

V

0

–1.0

–2.0

2.0

1.0

0

Figure 14. Output Saturation Voltage

versus Load Current

Source Saturation

V

CC

(Load to Ground)

VCC = 15 V

µ

s Pulsed Load

80

120 Hz Rate

°

TA = +25

0 0.2 0.4 0.6 0.8 1.0

C

Ground

IO, OUTPUT LOAD CURRENT (A)

Figure 15. Drive Output Rise and Fall Time Figure 16. Drive Output Rise and Fall Time

Sink Saturation

(Load to VCC)

OUTPUT RISE & FALL TIME 1.0 nF LOAD

50 ns/DIV

Figure 17. Supply V oltage versus Supply Current

30

RT = 3.65 k

25

20

15

10

, SUPPLY CURRENT (mA)

CC

5.0

I

CT = 1.0 nF

VCC Decreasing

0

0 4.0 8.0 12 16 20

OUTPUT RISE & FALL TIME 10.0 nF LOAD

50 ns/DIV

Ω

VCC Increasing

VCC, SUPPLY VOLT AGE (V)

6

MOTOROLA ANALOG IC DEVICE DATA