MAX8520ETP+T Datasheet MAX8520ETP+, MAX8521ETP+, MAX8521ETP+T | P4-P6

MAX8520/MAX8521

Smallest TEC Power Drivers for Optical

Modules

4 _______________________________________________________________________________________

ELECTRICAL CHARACTERISTICS

(V

DD

= V

PV

DD1

= V

PV

DD2

= V

SHDN

= 5V, 1MHz mode (Note 4). PGND1 = PGND2 = GND, CTLI = MAXV = MAXIP = MAXIN = REF,

T

A

= -40°C to +85°C, unless otherwise noted.) (Note 8)

PARAMETER SYMBOL CONDITIONS MIN MAX UNITS

Input Supply Range V

DD

3.0 5.5 V

Maximum TEC Current ±1.5 A

Reference Voltage V

REF

V

DD

= 3V to 5.5V, I

REF

= 150µA 1.480 1.515 V

Reference Load Regulation ∆V

REF

V

DD

= 3V to 5V, I

REF

= 10µA to 1mA 5 mV

V

MAXI_

= V

REF

140 160

V

DD

= 5V

V

MAXI_

= V

REF

/3 40 60

V

MAXI_

= V

REF

143 155

MAXIP/MAXIN Threshold

Accuracy

V

DD

= 3V

V

MAXI_

= V

REF

/3 45 55

mV

V

DD

= 5V, I = 0.2A 0.14

nFET On-Resistance R

DS

(

ON-N

)

V

DD

= 3V, I = 0.2A 0.16

Ω

V

DD

= 5V, I = 0.2A 0.23

pFET On-Resistance R

DS

(

ON-P

)

V

DD

= 3V, I = 0.2A 0.30

Ω

500kHz mode 14

V

COMP

= V

REF

=

1.500V, V

DD

= 5V

1MHz mode 21

500kHz mode 11

No Load Supply Current

I

DD(NO

LOAD)

V

COMP

= V

REF

=

1.500V, V

DD

= 3.3V

1MHz mode 14

mA

Shutdown Supply Current I

DD-SD

SHDN = GND, V

DD

= 5V (Note 5) 3 mA

V

DD

Rising 2.50 2.80

UVLO Threshold V

UVLO

V

DD

Falling 2.40 2.70

V

MAX8521, FREQ = V

DD

, V

DD

= 3V to 5V 0.8 1.2

MAX8521, FREQ = GND, V

DD

= 3V to 5V 0.4 0.6

MAX8520, R

EXT

= 60kΩ, V

DD

= 5V 0.8 1.2

MAX8520, R

EXT

= 60kΩ, V

DD

= 3V 0.76 1.10

MAX8520, R

EXT

= 150kΩ, V

DD

= 5V 0.4 0.6

Internal Oscillator Switching

Frequency

f

SW-INT

MAX8520, R

EXT

= 150kΩ, V

DD

= 3V 0.36 0.56

MHz

External Sync Frequency Range 25% < duty cycle < 75% (MAX8521 only) 0.7 1.2 MHz

LX_ Duty Cycle Note 6 0 100 %

OS1, OS2, CS Input Current

I

OS1

, I

OS2

,

I

CS

0V or V

DD

-100 +100 µA

SHDN, FREQ Input Current

I

SHDN

,

I

FREQ

0V or V

DD

, FREQ applicable for the

MAX8521 only

-5 +5 µA

SHDN, FREQ Input Low Voltage V

IL

V

DD

= 3V to 5.5V, FREQ applicable for the

MAX8521 only

V

DD

x

0.25

V

SHDN, FREQ Input High Voltage V

IH

V

DD

= 3V to 5.5V, FREQ applicable for the

MAX8521 only

V

DD

x

0.75

V

MAX8520/MAX8521

Smallest TEC Power Drivers for Optical

Modules

_______________________________________________________________________________________ 5

ELECTRICAL CHARACTERISTICS (continued)

(V

DD

= V

PV

DD1

= V

PV

DD2

= V

SHDN

= 5V, 1MHz mode (Note 4). PGND1 = PGND2 = GND, CTLI = MAXV = MAXIP = MAXIN = REF,

T

A

= -40°C to +85°C, unless otherwise noted.) (Note 8)

PARAMETER SYMBOL CONDITIONS MIN MAX UNITS

V

MAXV

= V

REF

x 0.67, V

OS1

to V

OS2

= ±4V,

V

DD

= 5V

-2 +2 %

MAXV Threshold Accuracy

V

MAXV

= V

REF

x 0.33, V

OS1

to V

OS2

= ±2V,

V

DD

= 3V

-3 +3 %

MAXV, MAXI_ Input Bias Current

I

MAXV-

BIAS

,

I

MAXI_-BIAS

V

MAXV

= V

MAXI_

= 0.1V or 1.5V -0.1 +0.1 µA

CTLI Gain A

CTLI

V

CTLI

= 0.5V to 2.5V (Note 7) 9.5 10.5 V/V

CTLI Input Resistance R

CTLI

1MΩ terminated at REF 0.5 2.0 MΩ

Error-Amp Transconductance g

m

50 160 µS

V

ITEC

Accuracy

V

OS1

to V

CS

= ±100mV

V

OS1

= V

DD

/2

-10 +10 %

Note 4: Enter 1MHz mode by connecting a 60kΩ resistor from FREQ to ground for the MAX8520, and connecting FREQ to V

DD

for

the MAX8521.

Note 5: Includes power FET leakage.

Note 6: Duty-cycle specification is guaranteed by design and not production tested.

Note 7: CTLI Gain is defined as:

Note 8: Specifications to -40°C are guaranteed by design and not production tested.

A

V

VV

CTLI

OS CS

=

−

()

∆

1

Typical Operating Characteristics

(V

DD

= 5V, circuit of Figure 1, T

A

= +25°C unless otherwise noted.)

EFFICIENCY vs. TEC CURRENT

V

DD

= 5V, R

TEC

= 2Ω

MAX8520/21 toc01

TEC CURENT (A)

EFFICIENCY (%)

1.41.20.8 10.4 0.60.2

10

20

30

40

50

60

70

80

90

0

0 1.6

FREQ = 500kHz

FREQ = 1MHz

EFFICIENCY vs. TEC CURRENT

V

DD

= 3.3V, R

TEC

= 1.3Ω

MAX8520/21 toc02

TEC CURRENT (A)

EFFICIENCY (%)

1.41.20.8 10.4 0.60.2

10

20

30

40

50

60

70

80

90

0

01.6

FREQ = 500kHz

FREQ = 1MHz

COMMON-MODE

OUTPUT VOLTAGE RIPPLE

MAX8520/21 toc03

400ns/div

V

OS2

20mV/div

AC-COUPLED

V

OS1

20mV/div

AC-COUPLED

I

TEC

= 1A

C

2

= C

7

= 1µF

MAX8520/MAX8521

Smallest TEC Power Drivers for Optical

Modules

6 _______________________________________________________________________________________

DIFFERENTIAL

OUTPUT VOLTAGE RIPPLE

MAX8520/21 toc04

400ns/div

V

OS2

- V

OS1

1mV/div

AC-COUPLED

C

2

= C

7

= 1µF

I

TEC

= 1A

V

DD

RIPPLE

MAX8520/21 toc05

400ns/div

V

DD

20mV/div

AC-COUPLED

I

TEC

= 1A

TEC CURRENT RIPPLE

MAX8520/21 toc06

400ns/div

10mA/div

AC-COUPLED

0A

1.5A

TEC CURRENT vs. CTLI VOLTAGE

MAX8520/21 toc07

20ms/div

V

CTLI

1V/div

I

TEC

1A/div

0A

0V

ZERO-CROSSING TEC CURRENT

MAX8520/21 toc08

1ms/div

V

CTLI

I00mV/div

I

TEC

100mA/div

0A

1.5V

V

ITEC

vs. TEC CURRENT

MAX8520/21 toc09

TEC CURRENT (A)

V

ITEC

(V)

1.51.00.50-0.5-1.0-1.5

0.5

1.0

1.5

2.0

2.5

3.0

0

-2.0 2.0

Typical Operating Characteristics (continued)

(V

DD

= 5V, circuit of Figure 1, T

A

= +25°C unless otherwise noted.)

I

TEC

vs. AMBIENT TEMPERATURE

MAX8520/21 toc10

AMBIENT TEMPERATURE (°C)

TEC CURRENT (A)

+60+40+200-20

0.460

0.470

0.480

0.490

0.500

0.510

0.520

0.450

-40 +80

FREQ = 1MHz

V

CTLI

= 2V

R

TEC

= 1Ω

SWITCHING FREQUENCY

vs. TEMPERATURE

MAX8520/21 toc11

TEMPERATURE (°C)

SWITCHING FREQUENCY (kHz)

+80+60+40+200-20

500

600

700

800

900

1000

1100

400

-40

FREQ = 1MHz

V

CTLI

= 1.5V

R

TEC

= 1Ω

FREQ = 500KHz

MAX8520ETP+T

MAX8520ETP+T

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