MAX3243EETJ+T Maxim Integrated, MAX3243EETJ+T Datasheet - Page 14

• Manufacturer Part Number: MAX3243EETJ+T
• Description: RS-232 Interface IC
• Manufacturer: Maxim Integrated
• Series: MAX3221E, MAX3223E, MAX3243Er

Specifications of MAX3243EETJ+T

• Data Rate: 120 Kbps
• Operating Supply Voltage: 3 V to 5.5 V
• Supply Current: 1 mA
• Operating Temperature Range: 0 C to + 70 C
• Function: Transceiver
• Number Of Drivers: 3
• Number Of I/os: 16
• Number Of Receivers: 5
• Propagation Delay Time Ns: 0.3 us
• Shutdown: Yes

3.0V to 5.5V, 1.25Gbps/2.5Gbps
LAN Laser Drivers
14
Q1 = general-purpose PNP,
B1 = ferrite bead (see Bias Filter section)
M1 = general-purpose PMOS device (optional)
In the common-cathode configuration with current feed-
back, a servo control loop is formed by an external PNP
transistor (Q1), R
block, R
(Figure 10). The voltage at MD is stabilized to 1.7V. The
voltage at MON is set by the resistors R
As in the short-wavelength configuration, a 0.1µF
C
Figure 9. Common-Cathode Laser with Photodiode
Figure 10. Common Cathode with Current Feedback (PNP Configuration)
BIASDRV
______________________________________________________________________________________
Common Cathode with Current Feedback
SET
connected between BIASDRV and V
, R
MD
MON
MAX3286
MAX3287
MAX3296
MAX3297
MAX3286
MAX3288
MAX3296
MAX3298
, and the power-control amplifier
, the controlled-reference voltage
>100, f
PHOTO
DIODE
I
D
I
R
D
R
SET
SET
t
R
> 5MHz
V
MD
V
CC
CC
SET
MD
REF
MAX3286/96
POL
POL
REF
POL
POL
MD
MAX3286/96
and R
ONLY
ONLY
CC
MD
CONTROLLED REFERENCE VOLTAGE
CONTROLLED REFERENCE VOLTAGE
V
is
REF
SMOOTH-
SMOOTH-
.
START
START
= 2.65V - 2.25V (V
V
REF
sufficient to obtain an approximate 1µs APC loop time
constant. This improves power-supply noise rejection.
To select the external components:
1) Determine the required laser bias current
2) Select R
3) Select R
= 2.65V
1.7V
1.7V
Maxim recommends R
results in V
R
SET
CC
- V
= 1k and R
POWER-CONTROL
AMPLIFIER
MON
POWER-CONTROL
AMPLIFIER
MON
MD
)
CC
SHDNDRV
SHDNDRV
and R
BIASDRV
BIASDRV
where R
- V
I
MON
MON
BIAS
FERRITE
FERRITE
MON
SET
MD
BEAD
BEAD
R
V
B1
MON
B1
= I
CC
.
MON
= 5k .
V
V
SET
TH
CC
CC
M1
M1
Q1
Q1
250mV.
R
LASER
DEG
+ I
LASER
= 250mV / I
= 1k , R
V
V
I
CC
BIAS
CC
MOD / 2
C
I
C
BIAS
BIASDRV
BIASDRV
MD
BIAS
= 5k , which
, assuming