Rainbow Electronics MAX5095A User Manual

General Description

The MAX5094A/B/C/D/MAX5095A/B/C BiCMOS, high­performance, current-mode PWM controllers have all the
features required for wide input-voltage range
isolated/nonisolated power supplies. These controllers
are used for low- and high-power universal input volt­age and telecom power supplies.

The MAX5094/MAX5095 contain a fast comparator with
only 60ns typical delay from current sense to the output
for overcurrent protection. The MAX5094 has an inte­grated error amplifier with the output at COMP. Soft­start is achieved by controlling the COMP voltage rise
using external components.

The oscillator frequency is adjustable from 20kHz to
1MHz with an external resistor and capacitor. The tim­ing capacitor discharge current is trimmed allowing for
programmable dead time and maximum duty cycle for
a given frequency. The available saw-toothed waveform
at RTCTcan be used for slope compensation when
needed.

The MAX5095A/MAX5095B include a bidirectional syn­chronization circuit allowing for multiple controllers to
run at the same frequency to avoid beat frequencies.
Synchronization is accomplished by simply connecting
the SYNC of all devices together. When synchronizing
with other devices, the MAX5095A/MAX5095B with the
highest frequency synchronizes the other devices.
Alternatively, the MAX5095A/MAX5095B can be syn­chronized to an external clock with an open-drain out­put stage running at a higher frequency.

The MAX5095C provides a clock output pulse
(ADV_CLK) that leads the driver output (OUT) by
110ns. The advanced clock signal is used to drive the
secondary-side synchronous rectifiers.

The MAX5094A/B/C are available in the 8-pin SO and
8-pin µMAX®packages. The MAX5094D and
MAX5095A/B/C are available in the 8-pin µMAX pack­age. All devices operate over the automotive tempera­ture range of -40°C to +125°C.

Applications

Universal Input AC/DC Power Supplies

Isolated Telecom Power Supplies

Isolated Power-Supply Modules

Networking Systems

Computer Systems/Servers

Industrial Power Conversion

Isolated Keep-Alive Circuits

Features

♦ Pin-for-Pin Replacement for UCC28C43

(MAX5094A) and UCC28C45 (MAX5094B)

♦ 2A Drive Source and 1A Sink Capability

♦ Up to 1MHz Switching Frequency Operation

♦ Bidirectional Frequency Synchronization

(MAX5095A/MAX5095B)

♦ Advanced Output Drive for Secondary-Side

Synchronous Rectification (MAX5095C)

♦ Fast 60ns Cycle-by-Cycle Current Limit

♦ Trimmed Oscillator Capacitor Discharge Current

Sets Maximum Duty Cycle Accurately

♦ Accurate ±5% Start Voltage with 0.8V Hysteresis

♦ Low 32µA Startup Current

♦ 5V Regulator Output (REF) with 20mA Capability

♦ Versions with 0.3V Current-Sense Threshold

MAX5094A/B/C/D/MAX5095A/B/C

High-Performance, Single-Ended, Current-Mode

PWM Controllers

________________________________________________________________ Maxim Integrated Products 1

OUT

GNDR

T/CT

1

2

87REF

V

CC

FB

CS

COMP

µMAX/SO

TOP VIEW

3

4

6

5

MAX5094

Pin Configurations

Ordering Information

19-3864; Rev 0; 10/05

For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.

PART

TEMP RANGE

PIN-

PKG

CODE

MAX5094AASA

8 SO S8-4

MAX5094AAUA

8 µMAX U8-1

MAX5094BASA*

8 SO S8-4

MAX5094BAUA*

8 µMAX U8-1

MAX5094CASA*

8 SO S8-4

MAX5094CAUA*

8 µMAX U8-1

MAX5094DAUA*

8 µMAX U8-1

MAX5095AAUA

8 µMAX U8-1

MAX5095BAUA*

8 µMAX U8-1

MAX5095CAUA*

8 µMAX U8-1

Pin Configurations continued at end of data sheet.

µMAX is a registered trademark of Maxim Integrated Products, Inc.

*Future product—contact factory for availability.

Ordering Information continued at end of data sheet.

PACKAGE

-40°C to +125°C

-40°C to +125°C

-40°C to +125°C

-40°C to +125°C

-40°C to +125°C

-40°C to +125°C

-40°C to +125°C

-40°C to +125°C

-40°C to +125°C

-40°C to +125°C

MAX5094A/B/C/D/MAX5095A/B/C

High-Performance, Single-Ended, Current-Mode
PWM Controllers

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(VCC= +15V, RT= 10kΩ, CT= 3.3nF, REF = open, C

REF

= 0.1µF, COMP = open, VFB= 2V, CS = GND, TA= TJ= -40°C to +85°C,

unless otherwise noted.) (Note 1)

Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.

VCC(Low-Impedance Source) to GND ..................-0.3V to +30V

V

CC(ICC

< 30mA).....................................................Self Limiting

OUT to GND ...............................................-0.3V to (V

CC

+ 0.3V)

OUT Current.............................................................±1A for 10µs

FB, SYNC, COMP, CS, R

T/CT

, REF to GND .............-0.3V to +6V

COMP Sink Current (MAX5094)..........................................10mA

Continuous Power Dissipation (T

A

= +70°C)

8-Pin µMAX (derate 4.5mW/°C above +70°C) .............362mW

8-Pin SO (derate 5.9mW/°C above +70°C)...............470.6mW

Operating Temperature Range .........................-40°C to +125°C

Maximum Junction Temperature .....................................+150°C

Storage Temperature Range .............................-65°C to +150°C

Lead Temperature (soldering, 10s) .................................+300°C

PARAMETER SYMBOL CONDITIONS

UNITS

REFERENCE

Output Voltage V

REF

TA = +25°C, I

REF

= 1mA

V

Line Regulation ∆V

LINE

12V ≤ V

CC

≤ 25V, I

REF

= 1mA 0.4 4 mV

Load Regulation ∆V

LOAD

1mA ≤ I

REF

≤ 20mA 6 25 mV

Total Output Variation V

REFT

1mA ≤ I

REF

≤ 20mA, 12V ≤ V

CC

≤ 25V 4.9 5.1 V

Reference Output-Noise Voltage

V

NOISE

10Hz ≤ f ≤ 10kHz, TA = +25°C 50 µV

Reference Output Short Circuit I

S_SC

V

REF =

0 -30

mA

OSCILLATOR

Initial Accuracy TA = +25°C 51 54 57 kHz
Voltage Stability 12V ≤ VCC ≤ 25V 0.2 0.5 %
Temp Stability -40°C ≤ TA ≤ +85°C 0.5 %

RT/CT Voltage Ramp (

P-P

)V

RAMP

1.7 V

RT/CT Voltage Ramp Valley

1.1 V

V

RT/CT

= 2V, TA = +25°C 7.9 8.3 8.7

Discharge Current I

DIS

V

RT/CT

= 2V, -40°C ≤ TA ≤ +85°C 7.5 8.3 9.0

mA

Frequency Range f

OSC

20

kHz

ERROR AMPLIFIER (MAX5094)

FB Input Voltage V

FB

FB shorted to COMP

2.5

V

FB Input Bias Current I

B(FB)

µA

Open-Loop Voltage Gain A

VOL

2V ≤ V

COMP

≤ 4V

dB

Unity-Gain Bandwidth f

GBW

1

MHz

Power-Supply Rejection Ratio PSRR 12V ≤ VCC ≤ 25V (Note 2) 60 80 dB

COMP Sink Current I

SINK

VFB = 2.7V, V

COMP

= 1.1V 2 6 mA

COMP Source Current I

SOURCE

VFB = 2.3V, V

COMP

= 5V

mA

COMP Output High Voltage V

COMPH

VFB = 2.3V, R

COMP

= 15kΩ to GND 5 5.8 V

COMP Output Low Voltage V

COMPL

VFB = 2.7V, R

COMP

= 15kΩ to REF 0.1 1.1 V

CURRENT-SENSE AMPLIFIER

(MAX5094A/MAX5094B)

3

V/V

Gain (Notes 3, 4) A

CS

(MAX5094C/D, MAX5095_)

3

V/V

MIN TYP MAX

4.950 5.000 5.050

-100 -180

V

RAMP_VALLEY

2.465

-0.01 -0.1

100

-0.5 -1.2 -1.8

2.85

2.85

1000

2.535

3.26

3.40

MAX5094A/B/C/D/MAX5095A/B/C

High-Performance, Single-Ended, Current-Mode

PWM Controllers

_______________________________________________________________________________________ 3

ELECTRICAL CHARACTERISTICS (continued)

(VCC= +15V, RT= 10kΩ, CT= 3.3nF, REF = open, C

REF

= 0.1µF, COMP = open, VFB= 2V, CS = GND, TA= TJ= -40°C to +85°C,

unless otherwise noted.) (Note 1)

PARAMETER SYMBOL CONDITIONS

UNITS

MAX5094A/B (Note 3)

1

MAX5094C/MAX5094D (Note 3)

0.3

Maximum Current-Sense Signal V

CS_MAX

V

COMP

= 5V, MAX5095

0.3

V

Power-Supply Rejection Ratio PSRR 12V ≤ VCC ≤ 25V 70 dB

Input Bias Current I

CS

V

COMP

= 0V -1

µA

Delay From CS to OUT

50mV overdrive 60 ns

MOSFET DRIVER

OUT Low-Side On-Resistance

I

SINK

= 200mA 4.5 10 Ω

OUT High-Side On-Resistance

I

SOURCE

= 100mA 3.5 7 Ω

I

SOURCE

(Peak) I

SOURCE

C

OUT

= 10nF 2 A

I

SINK

(Peak) I

SINK

C

OUT

= 10nF 1 A

Rise Time t

R

C

OUT

= 1nF 15 ns

Fall Time t

F

C

OUT

= 1nF 22 ns

UNDERVOLTAGE LOCKOUT/STARTUP

Startup Voltage Threshold

V

Minimum Operating Voltage After
Turn-On

V

CC_MIN

7.1 7.6 8.0 V

Undervoltage-Lockout Hysteresis

0.8 V

PWM

MAX5094A/MAX5094C/MAX5095A

96

Maximum Duty Cycle D

MAX

MAX5094B/MAX5094D/MAX5095B/
MAX5095C

48

50

%

Minimum Duty Cycle D

MIN

0%

SUPPLY CURRENT

Startup Supply Current I

START

VCC = 7.5V 32 65 µA

Operating Supply Current I

CC

VFB = VCS = 0 3 5 mA

Zener Bias Voltage at V

CC

V

Z

ICC = 25mA 24

V

SYNCHRONIZATION (MAX5095A/MAX5095B only) (Note 5)

SYNC Frequency Range f

SYNC

20

kHz

SYNC Clock Input High
Threshold

V

SYNCINH

3.5 V

SYNC Clock Input Low Threshold

V

SYNCINL

0.8 V

SYNC Clock Input Minimum
Pulse Width

ns

SYNC Clock Output High Level V

SYNCOH

1mA external pulldown 4.0 4.7 V

SYNC Clock Output Low Level V

SYNCOL

R

SYNC

= 5kΩ 0 0.1 V

SYNC Leakage Current I

SYNC

V

SYNC

= 0

0.1 µA

t

CS_DELAY

V

RDS_ONL

V

RDS_ONH

V

CC_START

UVLO

HYST

t

PW_SYNCIN

MIN TYP MAX

0.95

0.275

0.275

7.98 8.40 8.82

94.5

49.8

26.5

200

0.01

1.05

0.325

0.325

-2.5

97.5

1000

MAX5094A/B/C/D/MAX5095A/B/C

High-Performance, Single-Ended, Current-Mode
PWM Controllers

4 _______________________________________________________________________________________

ELECTRICAL CHARACTERISTICS (continued)

(VCC= +15V, RT= 10kΩ, CT= 3.3nF, REF = open, C

REF

= 0.1µF, COMP = open, VFB= 2V, CS = GND, TA= TJ= -40°C to +85°C,

unless otherwise noted.) (Note 1)

PARAMETER SYMBOL CONDITIONS

UNITS

ADV_CLK (MAX5095C only)

ADV_CLK High Voltage

I

ADV_CLK

= 10mA source 2.4 3 V

ADV_CLK Low Voltage

I

ADV_CLK

= 10mA sink 0.4 V

ADV_CLK Output Pulse Width t

PULSE

85 ns

ADV_CLK Rising Edge to OUT
Rising Edge

t

ADV_CLK

ns

ADV_CLK Source and Sink
Current

I

ADV_CLK

10 mA

ELECTRICAL CHARACTERISTICS

(VCC= +15V, RT= 10kΩ, CT= 3.3nF, REF = open, C

REF

= 0.1µF, COMP = open, VFB= 2V, CS = GND, TA= TJ= -40°C to +125°C,

unless otherwise noted.) (Note 1)

PARAMETER SYMBOL CONDITIONS

UNITS

REFERENCE

Output Voltage V

REF

TA = +25°C, I

REF

= 1mA

V

Line Regulation ∆V

LINE

12V ≤ V

CC

≤ 25V, I

REF

= 1mA 0.4 4 mV

Load Regulation ∆V

LOAD

1mA ≤ I

REF

≤ 20mA 6 25 mV

Total Output Variation V

REFT

1mA ≤ I

REF

≤ 20mA, 12V ≤ V

CC

≤ 25V 4.9 5.1 V

Reference Output-Noise Voltage

V

NOISE

10Hz ≤ f ≤ 10kHz, TA = +25°C 50 µV

Reference Output Short Circuit I

S_SC

V

REF

= 0 -30

mA

OSCILLATOR

Initial Accuracy TA = +25°C 51 54 57 kHz
Voltage Stability 12V ≤ VCC ≤ 25V 0.2 0.5 %
Temp Stability -40°C ≤ TA ≤ +125°C 1 %

RT/CT Voltage Ramp (

P-P

)V

RAMP

1.7 V

RT/CT Voltage Ramp Valley

1.1 V

V

RT/CT

= 2V, TA = +25°C 7.9 8.3 8.7

Discharge Current I

DIS

V

RT/CT

= 2V, -40°C ≤ TA ≤ +125°C 7.5 8.3 9.0

mA

Frequency Range f

OSC

20

kHz

ERROR AMPLIFIER (MAX5094)

FB Input Voltage V

FB

FB shorted to COMP

2.5

V

FB Input Bias Current I

B(FB)

µA

Open-Loop Voltage Gain A

VOL

2V ≤ V

COMP

≤ 4V

dB

Unity-Gain Bandwidth f

GBW

1

MHz

Power-Supply Rejection Ratio PSRR 12V ≤ VCC ≤ 25V (Note 2) 60 80 dB

COMP Sink Current I

SINK

V

FB

= 2.7V, V

COMP

= 1.1V 2 6 mA

COMP Source Current I

SOURCE

V

FB

= 2.3V, V

COMP

= 5V

mA

COMP Output High Voltage V

COMPH

V

FB

= 2.3V, R

COMP

=15kΩ to GND 5 5.8 V

COMP Output Low Voltage V

COMPL

V

FB

= 2.7V, R

COMP

= 15kΩ to REF 0.1 1.1 V

V

ADV_CLKH

V

ADV_CLKL

MIN TYP MAX

110

MIN TYP MAX

4.950 5.000 5.050

V

RAMP_VALLEY

-100 -180

2.465

-0.01 -0.1

100

-0.5 -1.2 -1.8

1000

2.535

MAX5094A/B/C/D/MAX5095A/B/C

High-Performance, Single-Ended, Current-Mode

PWM Controllers

_______________________________________________________________________________________ 5

ELECTRICAL CHARACTERISTICS (continued)

(VCC= +15V, RT= 10kΩ, CT= 3.3nF, REF = open, C

REF

= 0.1µF, COMP = open, VFB= 2V, CS = GND, TA= TJ= -40°C to +125°C,

unless otherwise noted.) (Note 1)

PARAMETER SYMBOL CONDITIONS

UNITS

CURRENT-SENSE AMPLIFIER

MAX5094A/MAX5094B

3

V/V

Gain (Notes 3, 4) A

CS

MAX5094C/D, MAX5095_

3

V/V

MAX5094A/B (Note 3)

1

MAX5094C/MAX5094D (Note 3)

Maximum Current-Sense Signal V

CS_MAX

V

COMP

= 5V, MAX5095_

V

Power-Supply Rejection Ratio PSRR 12V ≤ VCC ≤ 25V 70 dB

Input Bias Current I

CS

V

COMP

= 0V -1

µA

Delay From CS to OUT

50mV overdrive 60 ns

MOSFET DRIVER

OUT Low-Side On-Resistance

I

SINK

= 200mA 4.5 12 Ω

OUT High-Side On-Resistance

I

SOURCE

= 100mA 3.5 9 Ω

I

SOURCE

(Peak) I

SOURCE

C

OUT

= 10nF 2 A

I

SINK

(Peak) I

SINK

C

OUT

= 10nF 1 A

Rise Time t

R

C

OUT

= 1nF 15 ns

Fall Time t

F

C

OUT

= 1nF 22 ns

UNDERVOLTAGE LOCKOUT/STARTUP

Startup Voltage Threshold

8.4

V

Minimum Operating Voltage After
Turn-On

V

CC_MIN

7.1 7.6 8.0 V

Undervoltage-Lockout Hysteresis

0.8 V

PWM

MAX5094A/MAX5094C/MAX5095A

96

Maximum Duty Cycle D

MAX MAX5094B/MAX5094D/MAX5095B/

MAX5095C

48

50

%

Minimum Duty Cycle D

MIN

0%

SUPPLY CURRENT

Startup Supply Current I

START

VCC = 7.5V 32 65 µA

Operating Supply Current I

CC

VFB = VCS = 0 3 5 mA

Zener Bias Voltage at V

CC

V

Z

ICC = 25mA 24

V

SYNCHRONIZATION (MAX5095A/MAX5095B only, Note 5)

SYNC Frequency Range f

SYNC

20

kHz

SYNC Clock Input High
Threshold

3.5 V

SYNC Clock Input-Low Threshold

V

SYNCINL

0.8 V

SYNC Clock Input Minimum
Pulse Width

ns

SYNC Clock Output High Level V

SYNCOH

1mA external pulldown 4.0 4.7 V

SYNC Clock Output Low Level V

SYNCOL

R

SYNC

= 5kΩ 0 0.1 V

t

CS_DELAY

V

RDS_ONL

V

RDS_ONH

V

CC_START

UVLO

HYST

V

SYNCINH

t

PW_SYNCIN

MIN TYP MAX

2.85

2.85

0.95

0.275 0.300 0.325

0.275 0.300 0.325

7.98

94.5

49.8

26.5

200

3.26

3.40

1.05

-2.5

8.82

97.5

1000

MAX5094A/B/C/D/MAX5095A/B/C

High-Performance, Single-Ended, Current-Mode
PWM Controllers

6 _______________________________________________________________________________________

ELECTRICAL CHARACTERISTICS (continued)

(VCC= +15V, RT= 10kΩ, CT= 3.3nF, REF = open, C

REF

= 0.1µF, COMP = open, VFB= 2V, CS = GND, TA= TJ= -40°C to +125°C,

unless otherwise noted.) (Note 1)

PARAMETER SYMBOL CONDITIONS

UNITS

SYNC Leakage Current I

SYNC

V

SYNC

= 0

0.1 µA

ADV_CLK (MAX5095C only)

ADV_CLK High Voltage

I

ADV_CLK

= 10mA source 2.4 3 V

ADV_CLK Low Voltage

I

ADV_CLK

= 10mA sink 0.4 V

ADV_CLK Output Pulse Width t

PULSE

85 ns

ADV_CLK Rising Edge to OUT
Rising Edge

t

ADV_CLK

ns

ADV_CLK Source and Sink
Current

I

ADV_CLK

10 mA

Note 1:All devices are 100% tested at +25°C. All limits over temperature are guaranteed by design, not production tested.
Note 2: Guaranteed by design, not production tested.
Note 3: Parameter measured at trip point of latch with V

FB

= 0 (MAX5094 only).

Note 4: Gain is defined as A = ∆V

COMP

/ ∆VCS, 0 ≤ VCS≤ 0.8V for MAX5094A/MAX5094B, 0 ≤ VCS≤ 0.2V for

MAX5094C/MAX5094D/ MAX5095_.

Note 5: Output frequency equals oscillator frequency for MAX5094A/MAX5094C/MAX5095A. Output frequency is one-half oscillator

frequency for MAX5094B/MAX5094D/MAX5095B/MAX5095C.

Typical Operating Characteristics

(VCC= 15V, TA = +25°C, unless otherwise noted.)

BOOTSTRAP UVLO vs. TEMPERATURE

MAX5094/95 toc01

TEMPERATURE (°C)

V

CC

(V)

1109565 80-10 5 20 35 50-25

0

1

2

3

4

5

6

7

8

9

10

-40 125

VCC RISING

VCC FALLING

HYSTERESIS

25

27

39

31

29

33

35

37

41

-40 -10 5 20-25 35 50 9580 11065 125

START-UP CURRENT

vs. TEMPERATURE

MAX5094/95 toc02

TEMPERATURE (°C)

I

CC

(µA)

VCC = 7.5V

3.5

3.7

4.9

4.1

3.9

4.3

4.5

4.7

5.1

OPERATING SUPPLY CURRENT

vs. TEMPERATURE AFTER STARTUP

(f

OSC

= fSW = 300kHz)

MAX5094/95 toc03

I

CC

(mA)

-40 -10 5 20-25 35 50 9580 11065 125

TEMPERATURE (°C)

CT = 560pF

MAX5094A/MAX5094C/MAX5095A

V

ADV_CLKH

V

ADV_CLKL

MIN TYP MAX

0.01

110

MAX5094A/B/C/D/MAX5095A/B/C

High-Performance, Single-Ended, Current-Mode

PWM Controllers

_______________________________________________________________________________________ 7

Typical Operating Characteristics (continued)

(VCC= 15V, TA = +25°C, unless otherwise noted.)

4.90

4.94

4.92

5.00

4.98

4.96

5.02

5.04

5.06

5.08

REFERENCE VOLTAGE

vs. TEMPERATURE

MAX5094/95 toc04

V

REF

(V)

-40 -10 5 20-25 35 50 9580 11065 125

TEMPERATURE (°C)

I

REF

= 1mA

I

REF

= 20mA

4.65

4.75

4.70

4.85

4.80

5.00

4.95

4.90

5.05

02010 30 40 50 60 70

REFERENCE VOLTAGE

vs. REFERENCE LOAD CURRENT

MAX5094/95 toc05

I

REF

(mA)

V

REF

(V)

4.980

4.984

4.982

4.988

4.986

4.992

4.990

4.994

4.998

4.996

5.000

10 14 1612 18 20 22 24 26

REFERENCE VOLTAGE
vs. SUPPLY VOLTAGE

MAX5094/95 toc06

VCC (V)

V

REF

(V)

I

REF

= 1mA

450

470

460

500

490

480

510

520

540

530

550

-40 -10 5-25 20 3550658095110125

OSCILLATOR FREQUENCY (f

OSC

)

vs. TEMPERATURE

MAX5094/95 toc07

TEMPERATURE (°C)

OSCILLATOR FREQUENCY (kHz)

RT = 3.65kΩ
C

T

= 560pF

7.88

7.90

8.02

7.94

7.92

7.96

7.98

8.00

8.04

-40 -10 5 20-25 35 50 9580 11065 125

OSCILLATOR RT/CT DISCHARGE CURRENT

vs. TEMPERATURE

MAX5094/95 toc08

TEMPERATURE (°C)

R

T

/C

T

DISCHARGE CURRENT (mA)

V

RT/CT

= 2V

0

20

10

50

40

30

60

70

90

80

100

MAXIMUM DUTY CYCLE

vs. TEMPERATURE

MAX5094/95 toc09

DUTY CYCLE (%)

MAX5094A/MAX5094C/MAX5095A

-40 -10 5 20-25 35 50 9580 11065 125

TEMPERATURE (°C)

MAX5094B/MAX5094D/MAX5095B/MAX5095C

RT = 5kΩ
C

T

= 560pF

0 1000 1500500 2000 2500 3000 3500 4000

MAXIMUM DUTY CYCLE vs. FREQUENCY

MAX5094A/MAX5094C/MAX5095A

MAX5094/95 toc10

OSCILLATOR FREQUENCY (kHz)

CT = 100pF

CT = 220pF

CT = 560pF

CT = 1000pF

0

20

10

50

40

30

60

70

90

80

100

DUTY CYCLE (%)

0.90

0.94

0.92

1.00

0.98

0.96

1.02

1.04

1.08

1.06

1.10

CURRENT-SENSE TRIP THRESHOLD

vs. TEMPERATURE

MAX5094/95 toc11a

CS THRESHOLD (V)

MAX5094A/MAX5094B

-40 -10 5 20-25 35 50 9580 11065 125

TEMPERATURE (°C)

VFB = 0V

0.20

0.24

0.22

0.30

0.28

0.26

0.32

0.34

0.38

0.36

0.40

CURRENT-SENSE TRIP THRESHOLD

vs. TEMPERATURE

MAX5094/95 toc11b

CS THRESHOLD (V)

-40 -10 5 20-25 35 50 9580 11065 125

TEMPERATURE (°C)

MAX5094C/D: VFB = 0V
MAX5095_: V

COMP

= 5V

MAX5094A/B/C/D/MAX5095A/B/C

High-Performance, Single-Ended, Current-Mode
PWM Controllers

8 _______________________________________________________________________________________

Typical Operating Characteristics (continued)

(VCC= 15V, TA = +25°C, unless otherwise noted.)

TIMING RESISTANCE

vs. OSCILLATOR FREQUENCY

MAX5094/95 toc12

FREQUENCY (Hz)

R

T

(kΩ)

1,000,000100,000

1

10

100

1000

0.1
10,000 10,000,000

CT = 1nF

CT = 560pF

CT = 220pF

CT = 100pF

CT = 10nF

CT = 4.7nF

CT = 3.3nF

CT = 2.2nF

OUT IMPEDANCE vs. TEMPERATURE

(R

DS_ON

PMOS DRIVER)

MAX5094/95 toc13

TEMPERATURE (°C)

R

DS_ON

(Ω)

1109565 80-10 5 20 35 50-25

2.2

2.4

2.6

2.8

3.0

3.2

3.4

3.6

3.8

4.0

4.2

4.4

4.6

4.8

5.0

2.0

-40 125

I

SOURCE

= 100mA

0

2

1

5

4

3

6

7

9

8

10

OUT IMPEDANCE vs. TEMPERATURE

(R

DS_ON

NMOS DRIVER)

MAX5094/95 toc14

R

DS_ON

(Ω)

-40 -10 5 20-25 35 50 9580 11065 125

TEMPERATURE (°C)

I

SINK

= 200mA

0

20

10

50

40

30

60

70

90

80

100

PROPAGATION DELAY FROM CURRENT-LIMIT

COMPARATOR TO OUT vs. TEMPERATURE

MAX5094/95 toc15

PROPAGATION DELAY (ns)

-40 -10 5 20-25 35 50 9580 11065 125

TEMPERATURE (°C)

ERROR-AMPLIFIER OPEN-LOOP GAIN

AND PHASE vs. FREQUENCY

MAX5094/95 toc16

FREQUENCY (Hz)

GAIN (dB)

1M100k1k 10k10 1001

0

20

40

60

80

100

120

140

-20

0.01

100M

10M

-165

-140

-115

-90

-65

-40

-15

10

-190

PHASE

GAIN

PHASE (DEGREES)

1.5

1.6

2.2

1.8

1.7

1.9

2.0

2.1

2.3

-40 -10 5 20-25 35 50 9580 11065 125

COMP VOLTAGE LEVEL TO TURN

OFF DEVICE vs. TEMPERATURE

MAX5094/95 toc17

TEMPERATURE (°C)

V

COMP

(V)

VCC = 15V

100

104

102

110

108

106

112

114

118

116

120

ADV_CLK RISING EDGE TO OUT RISING

EDGE TIME vs. TEMPERATURE

MAX5094/95 toc18

TIME (ns)

-40 -10 5 20-25 35 50 9580 11065 125

TEMPERATURE (°C)

MAX5095C

t = 20ns/div

ADV_CLK AND OUT WAVEFORMS

OUT
10V/div

ADV_CLK
5V/div
LOAD = 4.75k

Ω

MAX5094/95 toc19

VCC = 15V
MAX5095C

MAX5094A/B/C/D/MAX5095A/B/C

High-Performance, Single-Ended, Current-Mode

PWM Controllers

_______________________________________________________________________________________ 9

Typical Operating Characteristics (continued)

(VCC= 15V, TA = +25°C, unless otherwise noted.)

Pin Descriptions

PIN NAME FUNCTION

1 COMP Error-Amplifier Output. COMP can be used for soft-start.

2FBError-Amplifier Inverting Input

3CS

PWM Comparator and Overcurrent Protection Comparator Input. The current-sense signal is
compared to a signal proportional to the error-amplifier output voltage.

4R

T/CT

Timing Resistor/Capacitor Connection. A resistor RT from RT/CT to REF and capacitor CT from RT/C

T

to GND set the oscillator frequency.

5 GND

Power-Supply Ground. Place the V

CC

and REF bypass capacitors close to the IC to minimize ground

loops.

6 OUT MOSFET Driver Output. OUT connects to the gate of the external n-channel MOSFET.

7V

CC

Power-Supply Input. Bypass VCC to GND with a 0.1µF ceramic capacitor or a parallel combination of
a 0.1µF and a higher value ceramic capacitor.

8 REF

5V Reference Output. Bypass REF to GND with a 0.1µF ceramic capacitor or a parallel combination
of a 0.1µF and a higher value ceramic capacitor no larger then 4.7µF.

MAX5094_

t = 400ns/div

OUT SOURCE AND SINK CURRENTS

I

OUT

4A/div

V

OUT

10V/div

MAX5094/95 toc20

VCC = 15V
C

OUT

= 10nF

2.0

3.0

2.5

4.0

3.5

5.0

4.5

5.5

6.5

6.0

7.0

20 220 320 420120 520 620 720 920820 1020

SUPPLY CURRENT

vs. OSCILLATOR FREQUENCY

MAX5094/95 toc21

FREQUENCY (kHz)

I

CC

(mA)

TA = +125°C

MAX5095C
C

T

= 100pF

TA = -40°C

MAXIMUM DUTY CYCLE

vs. R

T

MAX5094A/MAX5095A

MAX5094/95 toc22

RT (Ω)

DUTY CYCLE (%)

10,0001000

30

40

50

60

70

80

90

100

20

100 100,000

CT = 100nF

CT = 560pF

CT = 220pF

CT = 1000pF

MAX5094A/B/C/D/MAX5095A/B/C

High-Performance, Single-Ended, Current-Mode
PWM Controllers

10 ______________________________________________________________________________________

Pin Descriptions (continued)

PIN

MAX5095A/

MAX5095B

NAME FUNCTION

11COMP

Current Limit/PWM Comparator Input. COMP is level-shifted and connected to the
inverting input of the PWM comparator. Pull up COMP to REF through a resistor and
connect an optocoupler from COMP to GND for proper operation.

2—SYNC

Bidirectional Synchronization Input. When synchronizing with other
MAX5095A/MAX5095Bs, the higher frequency part synchronizes all other devices.

—2

Advance Clock Output. ADV_CLK is an 85ns clock output pulse preceding the rising
edge of OUT (see Figure 4). Use the pulse to drive the secondary-side synchronous
rectifiers through a pulse transformer or an optocoupler (see Figure 8).

33CS

PWM Comparator/Overcurrent Protection Comparator Input. The current-sense signal is
compared to the level shifted voltage at COMP.

44R

T/CT

Timing Resistor/Capacitor Connection. A resistor RT from RT/CT to REF and capacitor C

T

from RT/CT to GND set the oscillator frequency.

55GND

Power-Supply Ground. Place the V

CC

and REF bypass capacitors close to the IC to

minimize ground loops.

66OUT MOSFET Driver Output. OUT connects to the gate of the external n-channel MOSFET.

77V

CC

Power-Supply Input. Bypass VCC to GND with a 0.1µF ceramic capacitor or a parallel
combination of a 0.1µF and a higher value ceramic capacitor.

88REF

5V Reference Output. Bypass REF to GND with a 0.1µF ceramic capacitor or a parallel
combination of a 0.1µF and a higher value ceramic capacitor no larger than 4.7µF.

MAX5095_

MAX5095C

ADV_CLK

Detailed Description

The MAX5094_/MAX5095_ current-mode PWM con­trollers are designed for use as the control and regulation
core of flyback or forward topology switching power sup­plies. These devices incorporate an integrated low-side
driver, adjustable oscillator, error amplifier (MAX5094_
only), current-sense amplifier, 5V reference, and external
synchronization capability (MAX5095A/MAX5095B only).
An internal +26.5V current-limited VCCclamp prevents
overvoltage during startup.

Eight different versions of the MAX5094/MAX5095 are
available as shown in the Selector Guide. The
MAX5094A/MAX5094B are the standard versions with a

feedback input (FB) and internal error amplifier. The
MAX5095A/MAX5095B include bidirectional synchroniza­tion (SYNC). This enables multiple MAX5095A/
MAX5095Bs to be connected and synchronized to the
device with the highest frequency. The MAX5095C
includes an ADV_CLK output, which precedes the
MAX5095C’s drive output (OUT) by 110ns. Figures 1, 2,
and 3 show the internal functional diagrams of the
MAX5094_, MAX5095A/MAX5095B, and MAX5095C,
respectively. The MAX5094A/MAX5094C/MAX5095A are
capable of 100% maximum duty cycle. The MAX5094B/
MAX5094D/MAX5095B/MAX5095C limit the maximum
duty cycle to 50%.

MAX5094A/B/C/D/MAX5095A/B/C

High-Performance, Single-Ended, Current-Mode

PWM Controllers

______________________________________________________________________________________ 11

UVLO

REFERENCE

2.5V

PREREGULATOR

5V

VOLTAGE-

DIVIDER

THERMAL

SHUTDOWN

EN-REF

BG

SNS

V

DD

5V REGULATOR

VOLTAGE-

DIVIDER

8

7

26.5V

V

CC

REF

2.5V

VP

REG_OK

DELAY

SRQ

OSC Q

4

RT/C

T

6

OUT

ILIM

CPWM

1V (MAX5094A/B)

0.3V (MAX5094C/D)

EN-DRV-BAR

R

2R

VEA

3

5

2

1

CS

GND

FB

COMP

CLK

MAX5094_

VP

2.5V

8.4V/7.6V

100% MAX DUTY CYCLE (MAX5094A/MAX5094C)
50% MAX DUTY CYCLE (MAX5094B/MAX5094D)

Figure 1. MAX5094_ Functional Diagram

MAX5094A/B/C/D/MAX5095A/B/C

Current-Mode Control Loop

The advantages of current-mode control over voltage­mode control are twofold. First, there is the feed-forward
characteristic brought on by the controller’s ability to
adjust for variations in the input voltage on a cycle-by­cycle basis. Secondly, the stability requirements of the
current-mode controller are reduced to that of a single­pole system unlike the double pole in the voltage-mode
control scheme.

The MAX5094/MAX5095 use a current-mode control loop
where the output of the error amplifier is compared to the
current-sense voltage (VCS). When the current-sense sig­nal is lower than the inverting input of the CPWM com­parator, the output of the comparator is low and the
switch is turned on at each clock pulse. When the cur­rent-sense signal is higher than the inverting input of the
CPWM comparator, the output is high and the switch is
turned off.

High-Performance, Single-Ended, Current-Mode
PWM Controllers

12 ______________________________________________________________________________________

UVLO

REFERENCE

2.5V

PREREGULATOR

5V

VOLTAGE-

DIVIDER

THERMAL

SHUTDOWN

EN-REF

BG

SNS

V

DD

5V REGULATOR

VOLTAGE-

DIVIDER

8

7

26.5V

V

CC

REF

2.5V

VP

REG_OK

DELAY

SRQ

OSC Q

4

RT/C

T

6

OUT

ILIM

CPWM

0.3V

EN-DRV-BAR

R

2R

3

5

1

2

CS

GND

COMP

SYNC

CLK

MAX5095A
MAX5095B

VP

2.5V

BIDIRECTIONAL

SYNC

100% MAX DUTY CYCLE (MAX5095A)
50% MAX DUTY CYCLE (MAX5095B)

8.4V/7.6V

Figure 2. MAX5095A/B Functional Diagram

VCCand Startup

In normal operation, VCCis derived from a tertiary wind­ing of the transformer. However, at startup there is no
energy delivered through the transformer, thus a resistor
must be connected from V

CC

to the input power source

(see RSTand CSTin Figures 5 to 8). During startup, C

ST

charges up through RST. The 5V reference generator,
comparator, error amplifier, oscillator, and drive circuit
remain off during UVLO to reduce startup current below
65µA. When VCCreaches the undervoltage-lockout
threshold of 8.4V, the output driver begins to switch and
the tertiary winding supplies power to V

CC

. VCChas an
internal 26.5V current-limited clamp at its input to protect
the device from overvoltage during startup.

Size the startup resistor, R

ST

, to supply both the maxi-

mum startup bias (I

START

) of the device (65µA max)
and the charging current for CST. The startup capacitor
CSTmust charge to 8.4V within the desired time period
tST(for example, 500ms). The size of the startup
capacitor depends on:

1) IC operating supply current at a programmed oscilla-

tor frequency (f

OSC

).

2) The time required for the bias voltage, derived from

a bias winding, to go from 0 to 9V.

3) The MOSFET total gate charge.

4) The operating frequency of the converter (fSW).

MAX5094A/B/C/D/MAX5095A/B/C

High-Performance, Single-Ended, Current-Mode

PWM Controllers

______________________________________________________________________________________ 13

UVLO

REFERENCE

2.5V

PREREGULATOR

5V

VOLTAGE-

DIVIDER

THERMAL

SHUTDOWN

EN-REF

BG

SNS

V

DD

5V REGULATOR

VOLTAGE-

DIVIDER

8

7

26.5V

V

CC

REF

2.5V

VP

REG_OK

DELAY

SRQ

OSC Q

4

RT/C

T

6

OUT

ILIM

CPWM

0.3V

EN-DRV-BAR

R

2R

3

5

1

2

CS

GND

COMP

ADV_CLK

CLK

MAX5095C

VP

2.5V

50% MAX DUTY CYCLE

8.4V/7.6V

Figure 3. MAX5095C Functional Diagram

MAX5094A/B/C/D/MAX5095A/B/C

To calculate the capacitance required, use the following
formula:

where:

IG= QGf

SW

ICCis the MAX5094/MAX5095s’ maximum internal sup­ply current after startup (see the Typical Operating
Characteristics to find the IINat a given f

OSC

). QG is the
total gate charge for the MOSFET, fSWis the converter
switching frequency, V

HYST

is the bootstrap UVLO hys­teresis (0.8V), and tSSis the soft-start time, which is set
by external circuitry.

Size the resistor RSTaccording to the desired startup
time period, tST, for the calculated CST. Use the follow­ing equations to calculate the average charging current
(I

CST

) and the startup resistor (RST):

Where V

INMIN

is the minimum input supply voltage for

the application (36V for telecom), V

SUVR

is the bootstrap

UVLO wake-up level (8.4V), and I

START

is the VINsupply
current at startup (65µA, max). Choose a higher value for
RSTthan the one calculated above if longer startup times
can be tolerated to minimize power loss in R

ST

.

The equation for C

ST

above gives a good approximation
of CST, yet neglects the current through RST. Fine tune
CSTusing:

The above startup method is applicable to circuits where
the tertiary winding has the same phase as the output
windings. Thus, the voltage on the tertiary winding at any
given time is proportional to the output voltage and goes
through the same soft-start period as the output voltage.

The minimum discharge time of CSTfrom 8.4V to 7.6V
must be greater than the soft-start time (tSS).

Undervoltage Lockout (UVLO)

The minimum turn-on supply voltage for the
MAX5094/MAX5095 is 8.4V. Once VCCreaches 8.4V,
the reference powers up. There is 0.8V of hysteresis
from the minimum turn-on voltage to the UVLO thresh­old. Once VCCreaches 8.4V, the MAX5094/MAX5095
operates with V

CC

down to 7.6V. Once VCCgoes below

7.6V the device is in UVLO. When in UVLO, the quies­cent supply current into VCCfalls back to 32µA (typ),
and OUT and REF are pulled low.

MOSFET Driver

OUT drives an external n-channel MOSFET and swings
from GND to VCC. Ensure that VCCremains below the
absolute maximum VGSrating of the external MOSFET.
OUT is a push-pull output with the on-resistance of the
PMOS typically 3.5Ω and the on-resistance of the NMOS
typically 4.5Ω. The driver can source 2A typically and
sink 1A typically. This allows for the MAX5094/MAX5095
to quickly turn on and off high gate-charge MOSFETs.

Bypass VCCwith one or more 0.1µF ceramic capacitors
to GND, placed close to the MAX5094/MAX5095. The
average current sourced to drive the external MOSFET
depends on the total gate charge (QG) and operating
frequency of the converter. The power dissipation in the
MAX5094/MAX5095 is a function of the average output­drive current (I

DRIVE

). Use the following equation to cal-

culate the power dissipation in the device due to I

DRIVE

:

I

DRIVE

= QGx f

SW

PD = (I

DRIVE

+ ICC) x V

CC

where, ICCis the operating supply current. See the
Typical Operating Characteristics for the operating
supply current at a given frequency.

Error Amplifier (MAX5094)

The MAX5094 includes an internal error amplifier. The
inverting input is at FB and the noninverting input is inter­nally connected to a 2.5V reference. The internal error
amplifier is useful for nonisolated converter design (see
Figure 6) and isolated design with primary-side regulation
through a bias winding (see Figure 5). In the case of a
nonisolated power supply, the output voltage is:

where, R1 and R2 are from Figure 6.

V

R

R

V

OUT

=+











×1

1

2

25.

C

II

VV

R

V

t

ST

CC G

INMIN

ST

HYST

SS

=

+−

−































8

()

R

V

V

II

ST

INMIN

SUVR

CST START

≅

−











+

2

I

VC

t

CST

SUVR ST

ST

=

×

C

IIt

V

ST

CC G SS

HYST

=

+

[]

()

High-Performance, Single-Ended, Current-Mode
PWM Controllers

14 ______________________________________________________________________________________

MAX5095_Feedback

The MAX5095A/MAX5095B/MAX5095C use either an
external error amplifier when designed into a nonisolat­ed converter or an error amplifier and optocoupler
when designed into an isolated power supply. The
COMP input is level-shifted and connected to the
inverting terminal of the PWM comparator (CPWM).
Connect the COMP input to the output of the external
error amplifier for nonisolated design. Pull COMP high
externally to 5V (or REF) and connect the optocoupler
transistor as shown in Figures 7 and 8. COMP can be
used for soft-start and also as a shutdown. See the
Typical Operating Characteristics to find the turn-off
COMP voltage at different temperatures.

Oscillator

The oscillator frequency is programmed by adding an
external capacitor and resistor at RT/CT(see RTand C

T

in the Typical Application Circuits). RTis connected
from RT/CTto the 5V reference (REF) and CTis con­nected from RT/CTto GND. REF charges CTthrough R

T

until its voltage reaches 2.8V. CTthen discharges
through an 8.3mA internal current sink until CT’s voltage
reaches 1.1V, at which time CTis allowed to charge
through RTagain. The oscillator’s period will be the
sum of the charge and discharge times of CT. Calculate
the charge time as

tC= 0.57 x RTx C

T

The discharge time is then

The oscillator frequency will then be

For the MAX5094A/MAX5094C/MAX5095A, the convert­er output switching frequency (fSW) is the same as the
oscillator frequency (f

OSC

). For the MAX5094B/
MAX5094D/MAX5095B/MAX5095C, the output switch­ing frequency is 1/2 the oscillator frequency.

Reference Output

REF is a 5V reference output that can source 20mA.
Bypass REF to GND with a 0.1µF capacitor.

Current Limit

The MAX5094/MAX5095 include a fast current-limit com­parator to terminate the ON cycle during an overload or a
fault condition. The current-sense resistor (RCS), connect­ed between the source of the MOSFET and GND, sets
the current limit. The CS input has a voltage trip level
(VCS) of 1V (MAX5094A/B) or 0.3V (MAX5094C/D,
MAX5095_). Use the following equation to calculate RCS:

I

P-P

is the peak current in the primary that flows through
the MOSFET. When the voltage produced by this current
(through the current-sense resistor) exceeds the current­limit comparator threshold, the MOSFET driver (OUT) will
turn the switch off within 60ns. In most cases, a small RC
filter is required to filter out the leading-edge spike on the
sense waveform. Set the time constant of the RC filter at
50ns. Use a current transformer to limit the losses in the
current-sense resistor and achieve higher efficiency
especially at low input-voltage operation.

Synchronization (MAX5095A/MAX5095B)

SYNC

SYNC is a bidirectional input/output that outputs a syn­chronizing pulse and accepts a synchronizing pulse
from other MAX5095A/MAX5095Bs (see Figures 7 and

9). As an output, SYNC is an open-drain p-channel
MOSFET driven from the internal oscillator and requires
an external pulldown resistor (R

SYNC

) between 500Ω

and 5kΩ. As an input, SYNC accepts the output pulses
from other MAX5095A/MAX5095Bs.

Synchronize multiple MAX5095A/MAX5095Bs by con­necting their SYNC pins together. All devices connected
together will synchronize to the one operating at the
highest frequency. The rising edge of SYNC will precede
the rising edge of OUT by approximately the discharge
time (t

D

) of the oscillator (see the Oscillator section). The
pulse width of the SYNC output is equal to the time
required to discharge the stray capacitance at SYNC
through R

SYNC

plus the CTdischarge time tD. Adjust

RT/CTsuch that the minimum discharge time tDis 200ns.

R

V

I

CS

CS

PP

=

−

f

tt

OSC

CD

=

+

1

t

RC

R

D

TT

T

=

××

×−×

10

488 18 10

3

3

..

MAX5094A/B/C/D/MAX5095A/B/C

High-Performance, Single-Ended, Current-Mode

PWM Controllers

______________________________________________________________________________________ 15

MAX5094A/B/C/D/MAX5095A/B/C

Advance Clock Output (ADV_CLK) (MAX5095C)

ADV_CLK is an advanced pulse output provided to
facilitate the easy implementation of secondary-side
synchronous rectification using the MAX5095C. The
ADV_CLK pulse width is 85ns (typically) with its rising
edge leading the rising edge of OUT by 110ns. Use
this leading pulse to turn off the secondary-side syn­chronous-rectifier MOSFET (QS) before the voltage
appears on the secondary (see Figure 8). Turning off
the secondary-side synchronous MOSFET earlier
avoids the shorting of the secondary in the forward
converter. The ADV_CLK pulse can be propagated to
the secondary side using a pulse transformer or high­speed optocoupler. The 85ns pulse, with 3V drive volt­age (10mA source), significantly reduces the
volt-second requirement of the pulse transformer and
the advanced pulse alleviates the need for a high­speed optocoupler.

High-Performance, Single-Ended, Current-Mode
PWM Controllers

16 ______________________________________________________________________________________

t

ADV_CLK

= 110ns

t

PULSE

= 85ns

OUT

ADV_CLK

R

T/CT

Figure 4. ADV_CLK

Typical Application Circuits

R

T

R1

R2

1

2

4

3

REF

V

CC

GND

OUT

COMP

FB

R

T/CT

CS

8

7

5

6

MAX5094_

C

T

R

ST

V

IN

C

ST

V

OUT

N

R

CS

Figure 5. MAX5094_ Typical Application Circuit (Isolated Flyback with Primary-Side Regulation)

MAX5094A/B/C/D/MAX5095A/B/C

High-Performance, Single-Ended, Current-Mode

PWM Controllers

______________________________________________________________________________________ 17

Typical Application Circuits (continued)

R

T

R1

R2

1

2

4

3

REF

V

CC

GND

OUT

COMP

FB

R

T/CT

CS

8

7

5

6

MAX5094_

C

T

R

ST

V

IN

C

ST

R

CS

V

OUT

N

Figure 6. MAX5094_ Typical Application Circuit (Nonisolated Flyback)

R

T

1

2

4

3

REF

V

CC

GND

OUT

COMP

SYNC

R

T/CT

CS

8

7

5

6

MAX5095A
MAX5095B

C

T

R

ST

V

IN

C

ST

V

OUT

SYNC

INPUT/OUTPUT

N

R

SYNC

R

CS

Figure 7. MAX5095A/MAX5095B Typical Application Circuit (Isolated Flyback)

MAX5094A/B/C/D/MAX5095A/B/C

High-Performance, Single-Ended, Current-Mode
PWM Controllers

18 ______________________________________________________________________________________

Typical Application Circuits (continued)

MAX5095C

V

CC

GND

COMP

R

T/CT

REF

CS

OUT

R

T

C

T

V

IN

ADV_CLK

C

ST

R

ST

0.5V/µs PULSE TRANSFORMER

MAX5078

V

D

QR

N

N

N

QS

V

OUT

V

D

R

CS

Figure 8. MAX5095C Typical Application Circuit (Isolated Forward with Secondary-Side Synchronous Rectification)

MAX5094A/B/C/D/MAX5095A/B/C

High-Performance, Single-Ended, Current-Mode

PWM Controllers

______________________________________________________________________________________ 19

MAX5095A
MAX5095B

V

CC

GND

SYNC

R

T/CT

REF

CS

OUT

R

T

C

T

V

IN

MAX5095A
MAX5095B

V

CC

GND

SYNC

R

T/CT

REF

CS

OUT

R

T

C

T

V

IN

MAX5095A
MAX5095B

V

CC

GND

SYNC

R

T/CT

REF

CS

OUT

R

T

C

T

V

IN

TO OTHER
MAX5095A/Bs

R

SYNC

NN N

Figure 9. Synchronization of MAX5095A/MAX5095B

MAX5094A/B/C/D/MAX5095A/B/C

High-Performance, Single-Ended, Current-Mode
PWM Controllers

20 ______________________________________________________________________________________

Chip Information

TRANSISTOR COUNT: 1987

PROCESS: BiCMOS

OUT

GNDR

T/CT

1

2

87REF

V

CC

SYNC

CS

COMP

µMAX

TOP VIEW

3

4

6

5

MAX5095A
MAX5095B

OUT

GNDR

T/CT

1

2

87REF

V

CC

ADV_CLK

CS

COMP

µMAX

3

4

6

5

MAX5095C

Pin Configurations (continued)

Selector Guide

PART FEATURE

UVLO

(V)

CS

(V)

MAX DUTY

CYCLE

(%)

COMPETITORS PART

NUMBER

PIN-

PACKAGE

MAX5094AASA Feedback 8.4 1 100

8 SO

MAX5094AAUA Feedback 8.4 1 100

8 µMAX

MAX5094BASA Feedback 8.4 1 50

8 SO

MAX5094BAUA Feedback 8.4 1 50

8 µMAX

MAX5094CASA Feedback 8.4 0.3 100 Improved UCC28C43 8 SO

MAX5094CAUA Feedback 8.4 0.3 100 Improved UCC28C43 8 µMAX

MAX5094DAUA Feedback 8.4 0.3 50 Improved UCC28C45 8 µMAX

MAX5095AAUA Sync 8.4 0.3 100 Improved UCC28C43 8 µMAX

MAX5095BAUA Sync 8.4 0.3 50 Improved UCC28C45 8 µMAX

MAX5095CAUA ADV_CLK 8.4 0.3 50 Improved UCC28C45 8 µMAX

Ordering Information (continued)

PART

TEMP RANGE

PIN-

PKG

CODE

MAX5094AASA+

8 SO S8-4

MAX5094AAUA+

8 µMAX U8-1

MAX5094BASA+

8 SO S8-4

MAX5094BAUA+

8 µMAX U8-1

MAX5094CASA+*

8 SO S8-4

MAX5094CAUA+*

8 µMAX U8-1

MAX5094DAUA+*

8 µMAX U8-1

MAX5095AAUA+

8 µMAX U8-1

MAX5095BAUA+*

8 µMAX U8-1

MAX5095CAUA+

8 µMAX U8-1

+Denotes Lead-Free package

*Future product—contact factory for availability.

THRESHOLD

THRESHOLD

UCC28C43 2nd source

UCC28C43 2nd source

UCC28C45 2nd source

UCC28C45 2nd source

PACKAGE

-40°C to +125°C

-40°C to +125°C

-40°C to +125°C

-40°C to +125°C

-40°C to +125°C

-40°C to +125°C

-40°C to +125°C

-40°C to +125°C

-40°C to +125°C

-40°C to +125°C

MAX5094A/B/C/D/MAX5095A/B/C

High-Performance, Single-Ended, Current-Mode

PWM Controllers

______________________________________________________________________________________ 21

Package Information

(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information
go to www.maxim-ic.com/packages

.)

SOICN .EPS

PACKAGE OUTLINE, .150" SOIC

1

1

21-0041

B

REV.DOCUMENT CONTROL NO.APPROVAL

PROPRIETARY INFORMATION

TITLE:

TOP VIEW

FRONT VIEW

MAX

0.010

0.069

0.019

0.157

0.010

INCHES

0.150

0.007

E

C

DIM

0.014

0.004

B

A1

MIN

0.053A

0.19

3.80 4.00

0.25

MILLIMETERS

0.10

0.35

1.35

MIN

0.49

0.25

MAX

1.75

0.050

0.016L

0.40 1.27

0.3940.386D

D

MINDIM

D

INCHES

MAX

9.80 10.00

MILLIMETERS

MIN

MAX

16

AC

0.337 0.344 AB8.758.55 14

0.189 0.197 AA5.004.80 8

N MS012

N

SIDE VIEW

H 0.2440.228 5.80 6.20

e 0.050 BSC 1.27 BSC

C

HE

e

B

A1

A

D

0∞-8∞

L

1

VARIATIONS:

MAX5094A/B/C/D/MAX5095A/B/C

High-Performance, Single-Ended, Current-Mode
PWM Controllers

Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.

22 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600

© 2005 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products, Inc.

Package Information (continued)

(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information
go to www.maxim-ic.com/packages

.)

8LUMAXD.EPS

PACKAGE OUTLINE, 8L uMAX/uSOP

1

1

21-0036

J

REV.DOCUMENT CONTROL NO.APPROVAL

PROPRIETARY INFORMATION

TITLE:

MAX

0.043

0.006

0.014

0.120

0.120

0.198

0.026

0.007

0.037

0.0207 BSC

0.0256 BSC

A2

A1

c

e

b

A

L

FRONT VIEW

SIDE VIEW

E H

0.6±0.1

0.6±0.1

Ø0.50±0.1

1

TOP VIEW

D

8

A2

0.030

BOTTOM VIEW

1

6°

S

b

L

H

E

D

e

c

0°

0.010

0.116

0.116

0.188

0.016

0.005

8

4X S

INCHES

-

A1

A

MIN

0.002

0.950.75

0.5250 BSC

0.25 0.36

2.95 3.05

2.95 3.05

4.78

0.41

0.65 BSC

5.03

0.66
6°0°

0.13 0.18

MAX

MIN

MILLIMETERS

- 1.10

0.05 0.15

α

α

DIM