MAX8521 Maxim Integrated Products, MAX8521 Datasheet - Page 9

• Manufacturer Part Number: MAX8521
• Description: Smallest TEC Power Drivers
• Manufacturer: Maxim Integrated Products

TQFN
10
11
12
13
14
15
16
17
18
19
20
—
PIN
B2, B5, C3,
D6, D5, D4
E5, E6
B3, B4
E3, E4
UCSP
F5, F6
F1, F2
A5
A6
B6
C5
C6
C4
F4
F3
—
_______________________________________________________________________________________
Smallest TEC Power Drivers for Optical
PGND2
NAME
PV
PV
GND2
FREQ
GND
CTLI
N.C.
V
OS2
OS1
LX2
CS
EP
DD
DD
DD
2
1
TEC Current-Control Input. Sets TEC current. Center point is 1.50V (no TEC current). The
current is given by:
I
then V
Analog Ground. Star connect to PGND at underside exposed pad for TQFN package.
Analog Supply Voltage Input. Bypass V
For MAX8520: Analog FREQ Set Pin (see the Switching Frequency section).
For MAX8521: Digital FREQ Selection Pin. Connect to V
GND for 500kHz operation. The PWM oscillator can synchronize to FREQ by switching at
FREQ between 700kHz and 1.2MHz.
Power Ground 2. Internal synchronous rectifier ground connection. Connect all PGND
pins together at the power ground plane.
Inductor Connection. LX2 is high-impedance in shutdown.
Power Input 2. Connect all PV
Current-Sense Input. The current through the TEC is monitored between CS and OS1. The
maximum TEC current is given by 150mV/R
Output Sense 2. OS2 senses one side of the differential TEC voltage. OS2 is a sense
point, not a power output. OS2 discharges to ground in shutdown.
Output Sense 1. OS1 senses one side of the differential TEC voltage. OS1 is a sense
point, not a power output. OS1 discharges to ground in shutdown.
Power Input 1. Connect all PV
Ground. Additional ground pads aid in heat dissipation. Short to either GND or PGND
plane.
No Connect. Connect N.C. pads to GND2 to aid in heat dissipation.
Exposed Paddle (TQFN Only). Internally connected to GND. Connect to a large ground
plane to maximize thermal performance. Not intended as an electrical connection point.
TEC
= (V
OS2
OS1
> V
- V
OS1
CS
> V
) / R
CS
SENSE
.
= (V
DD
DD
inputs together at the V
inputs together at the V
CTLI
- 1.50) / (10 x R
DD
FUNCTION
Pin Description (continued)
to GND with a 1µF ceramic capacitor.
SENSE
and is bipolar.
SENSE
DD
DD
DD
for 1MHz operation, connect to
power plane.
power plane.
). When (V
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Modules
CTLI
- V
REF
) > 0
9