Datasheet
MAX8520/MAX8521
Smallest TEC Power Drivers for Optical
Modules
8 _______________________________________________________________________________________
Typical Operating Characteristics (continued)
(V
DD
= 5V, circuit of Figure 1, T
A
= +25°C unless otherwise noted.)
THERMAL STABILITY,
COOLING MODE
MAX8520/21 toc20
4s/div
TEMPERATURE
0.001°C/div
T
TEC
= +25°C
T
A
= +45°C
THERMAL STABILITY,
ROOM TEMPERATURE
MAX8520/21 toc21
4s/div
TEMPERATURE
0.001°C/div
T
TEC
= +25°C
T
A
= +25°C
THERMAL STABILITY,
HEATING MODE
MAX8520/21 toc22
4s/div
TEMPERATURE
0.001°C/div
T
TEC
= +25°C
T
A
= +5°C
Pin Description
PIN
TQFN UCSP/WLP
NAME
FUNCTION
1 E1, E2 LX1 Inductor Connection. LX1 is high-impedance in shutdown.
2 D1, D2, D3 PGND1
Power Ground 1. Internal synchronous-rectifier ground connection. Connect all PGND
pins together at power ground plane.
3C1SHDN Shutdown Control Input. Pull SHDN low to turn off PWM control and ITEC output.
4 C2 COMP Current-Control Loop Compensation. See the Compensation Capacitor section.
5 B1 ITEC
TEC Current-Monitor Output. The ITEC output voltage is a function of the voltage across
the TEC current-sense resistor. V
ITEC
= V
REF
+ 8 (V
OS
- V
CS
). Keep capacitance on ITEC
< 150pF.
6 A1 MAXIN
Maximum Negative TEC Current. Connect MAXIN to REF to set default negative current
limit to - 150mV/R
SENSE
. To lower this current limit, connect MAXIN to a resistor-divider
network from REF to GND. The current limit will then be equal to -(V
MAXIN
/V
REF
) x
(150mV/R
SENSE
).
7 A2 MAXIP
Maximum Positive TEC Current. Connect MAXIP to REF to set default positive current limit
to 150mV/R
SENSE
. To lower this current limit, connect MAXIP to a resistor-divider network
from REF to GND. The current limit will then be equal to (V
MAXIP
/V
REF
) x (150mV/R
SENSE
).
8 A3 MAXV
Maximum Bipolar TEC Voltage. Connect MAXV to REF to set default maximum TEC
voltage to V
DD
. To lower this limit, connect MAXV to a resistor-divider network from REF to
GND. The maximum TEC voltage is equal to 4 x V
MAXV
or V
DD
, whichever is lower.
9 A4 REF 1.50V Reference Output. Bypass REF to GND with a 0.1µF ceramic capacitor.