MAX3120 Maxim, MAX3120 Datasheet - Page 7

• Manufacturer Part Number: MAX3120
• Description: Low-Profile / 3V / 120A / IrDA Infrared Transceiver
• Manufacturer: Maxim

Power-dissipation requirements of the MAX3120, IR
LED, and R
cycle and output current requirements.
MAX3120 Power Dissipation = I
IR LED Power Dissipation = I
R
Because of the extremely sensitive nature of photodi-
ode amplifiers, it is important to maintain a quiet supply
voltage. Use a separate analog supply voltage where
possible. Place a 1µF ceramic bypass capacitor as
close to the V
systems, connect a small (10Ω) resistor in series with
V
CC
SET
, in addition to the normal bypass capacitor.
Power Dissipation = I
SET
CC
must be met based on maximum duty
Power-Supply Noise Rejection
_______________________________________________________________________________________
pin as possible. In especially noisy
SET 2
SET
SET
·
·
R
·
V
SET
V
LED
LEDC
·
·
Duty Cycle
Duty Cycle
·
Duty Cycle
IrDA Infrared Transceiver
Low-Profile, 3V, 120µA,
The MAX3120 requires careful layout techniques to mini-
mize parasitic signal coupling to the PINC input. Keep
the lead length between the photodiode and PINC as
short as possible. Be sure to keep PC board traces to
the PIN diode separate from other noisy traces. To mini-
mize coupling, run the AGND trace adjacent to the PINC
trace on both sides. To prevent oscillation, avoid routing
the RXD signal near the PINC signal. Connect the anode
of the PIN diode, the GND pin, and the supply bypass
capacitor pin in a star-ground connection. Connect
PGND and GND together. Reduce the output trace
length from RXD as much as possible to minimize cou-
pling back to the input via parasitic capacitance.
TRANSISTOR COUNT: 256
Package Information
Layout Considerations
Chip Information
7