MAX1329BETL+ Maxim Integrated Products, MAX1329BETL+ Datasheet - Page 65

• Manufacturer Part Number: MAX1329BETL+
• Description: IC DAS 12BIT 300KSPS 40-TQFN-EP
• Manufacturer: Maxim Integrated Products

Specifications of MAX1329BETL+

• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Figure 28 illustrates the MAX1329 in an optical reflectom-
etry application with two transmitting LEDs and one
receiving photodiode. The LEDs transmit light at specific
frequencies onto the sample strip and the photodiode
receives the reflections from the strip. Set the DACA out-
put to provide the appropriate bias currents for the LEDs.
Figure 28. Optical Reflectometry Application with Dual LED and Single Photodiode
12-/16-Bit DASs with ADC, DACs, DPIOs, APIOs,
Reference, Voltage Monitors, and Temp Sensor
Optical Reflectometry Application with
Dual LED and Single Photodiode
______________________________________________________________________________________
REFDAC
REFDAC
2.5V
REF
DACA
DACB
A
A
V
V
= 0.5, 0.82, 1
= 0.5, 0.82, 1
MAX1329
SPDT1
SPDT2
DSWB
DSWA
REFADC
REFDAC
REFADJ
OUTA
OUTB
SNO1
SCM1
SCM2
SNO2
SNC1
SNC2
FBA
FBB
1.25V
2.50V
The DSWA and DSWB switches are open in this configu-
ration. The LED bias current is calculated as I
V
DACB is set to ensure that the photodiode is not forward
biased. The I
the R
SPDT1 and SPDT2 are configured as single-pole
double-throw switches and enable switching between
OUTA
PHOTO
DIODE
I
F
F
/R
resistor and measured by the internal ADC.
B
. REFADC is used as an analog ground and
LED
V
R
F
BAT
F
Q
current is converted to a voltage through
1
0.01μF
1μF
1μF
LED
V
BAT
Q
2
R
B
LED
65
=