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MAX8521ETP+T

P1-P3P4-P6P7-P9P10-P12P13-P15P16-P18
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
Features
o Circuit Footprint 0.31in
2
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)
MAX8520/MAX8521
Smallest TEC Power Drivers for Optical
Modules
________________________________________________________________
Maxim Integrated Products
1
Ordering Information
19-2586; Rev 2; 2/11
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.
EVALUATION KIT
AVAILABLE
PART
TEMP RANGE
PIN-PACKAGE
MAX8520ETP+
-40°C to +85°C
20 TQFN - E P * 5m m x 5m m
MAX8521EBX
-40°C to +85°C
6 x 6 U C S P 3m m x 3m m
MAX8521ETP+
-40°C to +85°C
20 TQFN - E P * 5m m x 5m m
MAX8521EWX+
-40°C to +85°C
36 WLP ** 3m m x 3m m
UCSP is a trademark of Maxim Integrated Products, Inc.
INPUT
3V TO 5.5V
V
DD
PVDD_
COMP
GND
SHDN
ITEC
ON
OFF
TEC CURRENT
MONITOR
CTLI
LX1
PGND1
CS
OS1
OS2
LX2
PGND2
TEC
I
TEC
= ± 1.5A
REF
CURRENT-
CONTROL
SIGNAL
FREQ
ANALOG /DIGITAL
TEMPERATURE CONTROL
OUTPUT
MAX8521
Typical Operating Circuit
Pin Configurations appear at end of data sheet
+
Denotes a lead(Pb)-free/RoHS-compliant package.
*
EP = Exposed pad.
**
Four center bumps depopulated.
MAX8520/MAX8521
Smallest TEC Power Drivers for Optical
Modules
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
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.
V
DD
to GND..............................................................-0.3V to +6V
SHDN, MAXV, MAXIP, MAXIN,
CTLI to GND .........................................................-0.3V to +6V
COMP, FREQ, OS1, OS2, CS, REF,
ITEC to GND...........................................-0.3V to (V
DD
+ 0.3V)
PVDD1, PVDD2 to GND .............................-0.3V to (V
DD
+ 0.3V)
PVDD1, PVDD2 to V
DD
..........................................-0.3V to +0.3V
PGND1, PGND2 to GND .......................................-0.3V to +0.3V
COMP, REF, ITEC short to GND....................................Indefinite
LX Current (Note 1) ........................................±2.25A LX Current
Continuous Power Dissipation (T
A
= +70°C)
6 x 6 UCSP (derate 22mW/°C above +70°C) ...............1.75W
20-Pin 5mm x 5mm x 0.9mm TQFN (derate 20.8mW/°C
above +70°C) (Note 2)...................................................1.67W
36-Bump WLP (derate 22mW/°C above +70°C)............1.75W
Operating Temperature Range ...........................-40°C to +85°C
Maximum Junction Temperature .....................................+150°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
Soldering Temperature (reflow)
Lead(Pb)-Free (TQFN, WLP)........................................+260°C
Containing Lead (UCSP)............................................. +240°C
ELECTRICAL CHARACTERISTICS
(V
DD
= V
PVDD1
= V
PVDD2
= V
SHDN
= 5V, 1MHz mode (Note 4). PGND1 = PGND2 = GND, CTLI = MAXV = MAXIP = MAXIN = REF,
T
A
= 0°C to +85°C, unless otherwise noted. Typical values at T
A
= +25°C.)
PARAMETER SYMBOL CONDITIONS MIN TYP 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 1.485 1.500 1.515 V
Reference Load Regulation ∆V
REF
V
DD
= 3V to 5V, I
REF
= 10µA to 1mA 1.2 5.0 mV
V
MAXI_
= V
REF
140 150 160
V
DD
= 5V
V
MAXI_
= V
REF
/3 40 50 60
V
MAXI_
= V
REF
143 150 155
MAXIP/MAXIN Threshold
Accuracy
V
DD
= 3V
V
MAXI_
= V
REF
/3 45 50 55
mV
V
DD
= 5V, I = 0.2A 0.09 0.14
nFET On-Resistance R
DS
(
ON-N
)
V
DD
= 3V, I = 0.2A 0.11 0.16
Ω
V
DD
= 5V, I = 0.2A 0.14 0.23
pFET On-Resistance R
DS
(
ON-P
)
V
DD
= 3V, I = 0.2A 0.17 0.30
Ω
V
LX
= V
DD
= 5V, T
A
= +25°C 0.03 4.00
nFET Leakage I
LEAK(N)
V
LX
= V
DD
= 5V T
A
= +85°C 0.3
µA
V
LX
= 0V, T
A
= +25°C 0.03 4.00
pFET Leakage I
LEAK(P)
V
LX
= 0V, T
A
= +85°C 0.3
µA
Note 1: LX has internal clamp diodes to PGND and PVDD. Applications that forward bias these diodes should take care not to
exceed the IC’s package power dissipation limits.
Note 2: Solders underside metal slug to PCB ground plane.
PACKAGE THERMAL CHARACTERISTICS (Note 3)
20 TQFN
Junction-to-Ambient Thermal Resistance (θ
JA
)...............30°C/W
Junction-to-Case Thermal Resistance (θ
JC
)......................2°C/W
6x6 UCSP
Junction-to-Ambient Thermal Resistance (θ
JA
)................65.5°C/W
Junction-to-Case Thermal Resistance (θ
JC
).......................0°C/W
36 WLP
Junction-to-Ambient Thermal Resistance (θ
JA
)..................38°C/W
Junction-to-Case Thermal Resistance (θ
JC
)......................4°C/W
Note 3: Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a four-
layer board. For detailed information on package thermal considerations, refer to www.maxim-ic.com/thermal-tutorial
.
MAX8520/MAX8521
Smallest TEC Power Drivers for Optical
Modules
_______________________________________________________________________________________ 3
ELECTRICAL CHARACTERISTICS (continued)
(V
DD
= V
PVDD1
= V
PVDD2
= V
SHDN
= 5V, 1MHz mode (Note 4). PGND1 = PGND2 = GND, CTLI = MAXV = MAXIP = MAXIN = REF,
T
A
= 0°C to +85°C, unless otherwise noted. Typical values at T
A
= +25°C.)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
500kHz mode 11 14
V
COMP
= V
REF
=
1.500V, V
DD
= 5V
1MHz mode 16 21
500kHz mode 8 11
No-Load Supply Current
I
DD(NO
LOAD)
V
COMP
= V
REF
=
1.500V, V
DD
= 3.3V
1MHz mode 11 14
mA
Shutdown Supply Current I
DD-SD
SHDN = GND, V
DD
= 5V, (Note 5) 2 3 mA
Thermal Shutdown T
SHUTDOWN
Hysteresis = 15°C +165 °C
V
DD
rising 2.50 2.65 2.80
UVLO Threshold V
UVLO
V
DD
falling 2.40 2.55 2.70
V
MAX8521, FREQ = V
DD
, V
DD
= 3V to 5V 0.8 1.0 1.2
MAX8521, FREQ = GND, V
DD
= 3V to 5V 0.4 0.5 0.6
MAX8520, R
EXT
= 60kΩ, V
DD
= 5V 0.8 1.0 1.2
MAX8520, R
EXT
= 60kΩ, V
DD
= 3V 0.76 0.93 1.10
MAX8520, R
EXT
= 150kΩ, V
DD
= 5V 0.4 0.5 0.6
Internal Oscillator Switching
Frequency
f
SW-INT
MAX8520, R
EXT
= 150kΩ, V
DD
= 3V 0.36 0.46 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
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 10.0 10.5 V/V
CTLI Input Resistance R
CTLI
1MΩ terminated at REF 0.5 1.0 2.0 MΩ
Error-Amp Transconductance g
m
50 100 160 µS
V
ITEC
Accuracy
V
OS1
to V
CS
= ±100mV
V
OS1
= V
DD
/2
-10 +10 %
P1-P3P4-P6P7-P9P10-P12P13-P15P16-P18

MAX8521ETP+T

Mfr. #:
Buy MAX8521ETP+T
Manufacturer:
Maxim Integrated
Description:
Power Management Specialized - PMIC TEC Power Driver for Optical Modules
Lifecycle:
New from this manufacturer.
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