MAX8520_11 Datasheet, PDF (1/18 Pages) Maxim Integrated Products – Smallest TEC Power Drivers for Optical Modules Low Profile Design

19-2586; Rev 2; 2/11
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Smallest TEC Power Drivers for Optical
Modules
General Description
The MAX8520/MAX8521 are designed to drive thermo-
electric coolers (TECs) in space-constrained optical
modules. Both devices deliver ±1.5A output current
and control the TEC current to eliminate harmful current
surges. On-chip FETs minimize external components
and high switching frequency reduces the size of exter-
nal components.
The MAX8520/MAX8521 operate from a single supply and
bias the TEC between the outputs of two synchronous
buck regulators. This operation allows for temperature
control without “dead zones” or other nonlinearities at
low current. This arrangement ensures that the control
system does not hunt when the set-point is very close
to the natural operating point, requiring a small amount
of heating or cooling. An analog control signal precisely
sets the TEC current.
Both devices feature accurate, individually-adjustable
heating current limit and cooling current limit along with
maximum TEC voltage limit to improve the reliability of
optical modules. An analog output signal monitors the
TEC current. A unique ripple cancellation scheme helps
reduce noise.
The MAX8520 is available in a 5mm x 5mm TQFN pack-
age and its switching frequency is adjustable up to
1MHz through an external resistor. The MAX8521 is
also available in a 5mm x 5mm TQFN as well as
space-saving 3mm x 3mm UCSP™ and 36-bump WLP
(3mm x 3mm) packages, with a pin-selectable switch-
ing frequency of 500kHz or 1MHz.
Applications
SFF/SFP Modules
Fiber Optic Laser Modules
Fiber Optic Network Equipment
ATE
Biotech Lab Equipment
Pin Configurations appear at end of data sheet
UCSP is a trademark of Maxim Integrated Products, Inc.
Features
o Circuit Footprint 0.31in²
o Low Profile Design
o On-Chip Power MOSFETs
o High-Efficiency Switch-Mode Design
o Ripple Cancellation for Low Noise
o Direct Current Control Prevents TEC Current
Surges
o 5% Accurate Adjustable Heating/Cooling Current
Limits
o 2% Accurate TEC Voltage Limit
o No Dead Zone or Hunting at Low Output Current
o ITEC Monitors TEC Current
o 1% Accurate Voltage Reference
o Switching Frequency up to 1MHz
o Synchronization (MAX8521)
Ordering Information
PART
TEMP RANGE
PIN-PACKAGE
MAX8520ETP+
MAX8521EBX
MAX8521ETP+
MAX8521EWX+
-40°C to +85°C 20 TQFN-EP* 5mm x 5mm
-40°C to +85°C 6 x 6 UCSP 3mm x 3mm
-40°C to +85°C 20 TQFN-EP* 5mm x 5mm
-40°C to +85°C 36 WLP** 3mm x 3mm
+Denotes a lead(Pb)-free/RoHS-compliant package.
*EP = Exposed pad.
**Four center bumps depopulated.
Typical Operating Circuit
INPUT
3V TO 5.5V
ON
OFF
TEC CURRENT
MONITOR
CURRENT-
CONTROL
SIGNAL
VDD
PVDD_
FREQ
LX1
PGND1
SHDN
CS
ITEC MAX8521
CTLI
OS1
COMP
REF
GND
OS2
LX2
PGND2
ANALOG /DIGITAL
TEMPERATURE CONTROL
OUTPUT
TEC ^{ITEC = ± 1.5A}
________________________________________________________________ Maxim Integrated Products 1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.