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MAXIM INTEGRATED PRODUCTS MAX8520 MAX8521 Smallest TEC Power Drivers for Optical Modules

Summary

Optimize temperature control for high-density optical modules using the MAX8520/MAX8521 TEC Power Drivers. These compact, high-efficiency drivers deliver precise $\pm$1.5A current output while maintaining stable operation and eliminating noise in space-constrained systems. Ideal for network equipment, fiber optics, and biotech applications needing reliable thermal management. The manual provides essential details on implementation, specifications, and integration guidelines needed for superior performance.

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Page 1 Text Content

IO IT /M IL

19-2586; Rev 0; 10/02

5mm x 5mm

3mm x 3mm QFN Smallest TEC Power Drivers for CSP

Optical Modules

General Description Features

The MAX8520/MAX8521 are designed to drive thermo- Circuit Footprint of 0.31in2 electric coolers (TECs) in space-constrained optical

Low-Profile Design

modules. Both devices deliver ±1.5A output current and control the TEC current to eliminate harmful current

On-Chip Power MOSFETs

surges. On-chip FETs minimize external components and

High-Efficiency Switch-Mode Design

high switching frequency reduces the size of external components.

Ripple Cancellation for Low Noise

The MAX8520 and MAX8521 operate from a single supply

Direct Current Control Prevents TEC Current

and bias the TEC between the outputs of two synchro-

Surges

nous buck regulators. This operation allows for temper- ature control without “dead zones” or other nonlinearities 5% Accurate Adjustable Heating/Cooling Current at low current. This arrangement ensures that the control

Limits

system does not hunt when the set point is very close to

2% Accurate TEC Voltage Limit

the natural operating point, requiring a small amount of heating or cooling. An analog control signal precisely No Dead Zone or Hunting at Low Output Current sets the TEC current.

ITEC Monitors TEC Current

Both devices feature accurate, individually adjustable

heating current limit and cooling current limit, along 1% Accurate Voltage Reference

with maximum TEC voltage limit to improve the reliability

Switching Frequency Up to 1MHz

of optical modules. An analog output signal monitors

the TEC current. A unique ripple cancellation scheme Synchronization (MAX8521)

helps reduce noise. The MAX8520 is available in a 5mm x 5mm thin QFN package and its switching frequency is adjustable up to

1MHz through an external resistor. The MAX8521 is also Ordering Information

available in a 5mm x 5mm thin QFN, as well as a space-

PART TEMP RANGE PIN-PACKAGE

saving 3mm x 3mm UCSP™, with a pin-selectable

switching frequency of 500k Hz or 1MHz. MAX8520ETP -40°C to +85°C 20 Thin QFN 5mm x 5mm MAX8521EBX -40°C to +85°C 36 UCSP 3mm x 3mm

Applications

MAX8521ETP -40°C to +85°C 20 Thin QFN 5mm x 5mm

SFF/SFP Modules Fiber-Optic Laser Modules Fiber-Optic Network Equipment

Typical Operating Circuit

ATE Biotech Lab Equipment

INPUT VDD LX1 3V TO 5.5V PVDD

FREQ PGND1

SHDN CS

TEC CURRENT

ITEC MAX8521

MONITOR

CURRENT- OS1 OUTPUT

CONTROL ITEC = ± 1.5A

SIGNAL OS2

GND PGND2

Pin Configurations appear at end of data sheet.

ANALOG /DIGITAL TEMPERATURE CONTROL

UCSP is a trademark of Maxim Integrated Products, Inc.

Maxim Integrated Products

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.

Page Summary Contents For MAXIM INTEGRATED PRODUCTS MAX8520 MAX8521 Smallest TEC Power Drivers for Optical Modules

Page 1 IO IT /M IL 19-2586; Rev 0; 10/02 5mm x 5mm 3mm x 3mm QFN Smallest TEC Power Drivers for CSP Optical Modules General Description Features The MAX8520/MAX8521 are designed to drive thermo- Circuit Foot...
Page 2 Smallest TEC Power Drivers for Optical Modules ABSOLUTE MAXIMUM RATINGS VDD to GND..............................................................-0.3V to +6V Continuous Power Dissipation (TA = +70°C) S...
Page 3 Smallest TEC Power Drivers for Optical Modules ELECTRICAL CHARACTERISTICS (continued) (VDD = PVDD1 = PVDD2 = SHDN = 5V, 1MHz mode (Note 3). PGND1 = PGND2 = GND, CTLI = MAXV = MAXIP = MAXIN = REF, TA =...
Page 4 Smallest TEC Power Drivers for Optical Modules ELECTRICAL CHARACTERISTICS (VDD = PVDD1 = PVDD2 = SHDN = 5V, 1MHz mode (Note 2). PGND1 = PGND2 = GND, CTLI = MAXV = MAXIP = MAXIN = REF, TA -40°C to +85°...
Page 5 /M EF FI CI EN CY Smallest TEC Power Drivers for Optical Modules ELECTRICAL CHARACTERISTICS (continued) (VDD = PVDD1 = PVDD2 = SHDN = 5V, 1MHz mode (Note 2). PGND1 = PGND2 = GND, CTLI = MAXV = MAXIP =...
Page 6 Smallest TEC Power Drivers for Optical Modules TE CU RR EN (A Typical Operating Characteristics (continued) (VDD = 5V, circuit of Figure 1, TA = +25°C, unless otherwise noted) DIFFERENTIAL OUTPUT VOLT...
Page 7 /M RE FE RE NC VO LT AG CH AN GE (m V) SW IT CH IN FR EQ UE NC CH AN GE (k Hz Smallest TEC Power Drivers for Optical Modules Typical Operating Characteristics (continued) (VDD = 5V, circuit of Figure ...
Page 8 Smallest TEC Power Drivers for Optical Modules Typical Operating Characteristics (continued) (VDD = 5V, circuit of Figure 1, TA = +25°C unless otherwise noted) THERMAL STABILITY, THERMAL STABILITY, TH...
Page 9 Smallest TEC Power Drivers for Optical Modules Pin Description (continued) NAME FUNCTION QFN UCSP TEC Current-Control Input. Sets TEC current. Center point is 1.50V (no TEC current). The current is gi...
Page 10 Smallest TEC Power Drivers for Optical Modules Detailed Description Table 1. TEC Connection for Figure 1 The MAX8520/MAX8521 TEC drivers consist of two TEC CONNECTION THERMISTOR switching buck regulat...
Page 11 Smallest TEC Power Drivers for Optical Modules VDD LX1 RSENSE 0.09Ω PVDD1 C3 1µF RTHER PGND1 PVDD2 C4 MAX8521 1µF OS2 PGND2 REF LX2 0.1µF COMP VDD 1µFC8 MAXIP MAXIN FREQ 100kΩ CTLI GND MAX4477 MAX4475...
Page 12 Smallest TEC Power Drivers for Optical Modules REFLX1 RSENSE 0.09Ω PVDD1 RTHER PGND1 PVDD2 C4 MAX8520 1µF OS2 PGND2 REF LX2 0.1µF COMP 1µFC8 MAXIP MAXIN FREQ MAXV ON 100kΩ OFF CTLI GND MAX4238 REF VDD...
Page 13 Smallest TEC Power Drivers for Optical Modules 3/4 VDD 1/4 VDD PWM 4X RSENSE CCOMP CSREF 10X OS1 Figure 3. Functional Diagram of the Current-Control Loop Inductor Selection Calculate the inductor valu...
Page 14 Smallest TEC Power Drivers for Optical Modules The output common-mode ripple voltage can be calcu- bypassing may be needed to stabilize the input supply. lated as follows: In such cases, a low-ESR ele...
Page 15 Smallest TEC Power Drivers for Optical Modules Take care not to exceed the positive or negative cur- Applications Information rent limit on the TEC. Refer to the manufacturer’s data The MAX8520/MAX852...
Page 16 Smallest TEC Power Drivers for Optical Modules 6) To ensure high DC loop gain and minimum loop Refer to the MAX8520/MAX8521 evaluation kit for a PC AX IN PV error, keep the board layout adjacent to th...
Page 17 Smallest TEC Power Drivers for Optical Modules Functional Diagram SHDN FREQ (MAX8521) REF 3V TO PVDD1 MAX VTEC = VMAXV × 4 OR VDD MAX ITEC = MAXIP (VMAXIP/VREF) × (0.15V/RSENSE) PWM CONTROL PGND1 AND ...
Page 18 Smallest TEC Power Drivers for Optical Modules Package Information (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline informatio...
Page 19 Smallest TEC Power Drivers for Optical Modules Package Information (continued) (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outlin...

Manual Details

Brand Maxim Integrated
Pages 19
File Size 605.71 KB
Published May 26, 2026
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Frequently Asked Questions

What voltage range can the device operate from?

The MAX8520/MAX8521 devices operate from a single supply ranging between 3V and 5.5V.

How do these drivers handle high-frequency noise?

They use a unique ripple cancellation scheme to reduce noise, and the MAX8521 supports TEC current synchronization.

Is this product suitable for highly space-constrained modules?

Yes, they are designed specifically for optical modules in space-constrained environments and offer low-profile packages.

What is the maximum switching frequency supported?

The device's switching frequency can be adjustable up to 1MHz through an external resistor.