Datasheet
ADPD1080/ADPD1081 Data Sheet
Rev. B | Page 32 of 74
16110-039
PDC
PD5
PD6
PD7
PD8
7
15
8 14
PD1
PD2
PD3
PD4
PDC
7
15
8 14
PD1
PDC
7
15
8 14
PD1
PD2
PD3
PD4
PDC
7
15
8 14
PD1
PDC
PD5
7
15
8 14
PD1 PD8
PD3
PD4
PDC
PD5
PD6
7
15
8 14
PD2
PD7
PD1 PD8
PD3
PD4
PDC
PD5
PD6
7
15
8 14
PD2
PD7
Figure 39. Photodiode Configuration Options for the ADPD1080 LFCSP
Table 22. Typical Photodiode Anode to Input Channel Connections for the ADPD1080 LFCSP
1, 2
Input Channel
Photodiode Anode Configuration PD1 PD2 PD3 PD4 PD5 PD6 PD7 PD8
Single Photodiode (PD1) D1 NC NC NC NC NC NC NC
NC NC NC NC D1 NC NC NC
D1 D1 D1 D1 NC NC NC NC
NC NC NC NC D1 D1 D1 D1
Two Photodiodes (PD1, PD2) D1 NC NC NC D2 NC NC NC
D1 D1 D1 D1 D2 D2 D2 D2
Four Photodiodes (PD1 to PD4) D1 D2 D3 D4 NC NC NC NC
NC NC NC NC D1 D2 D3 D4
Eight Photodiodes (PD1 to PD8) D1 D2 D3 D4 D5 D6 D7 D8
1
Dx refers to the diode connected to the specified channel.
2
NC means do not connect. Leave all unused inputs floating.
LED DRIVER PINS AND LED SUPPLY VOLTAGE
The LEDX1, LEDX2, and LEDX3 pins have an absolute maximum
voltage rating of 3.6 V. Any voltage exposure over this rating affects
the reliability of the device operation and, in certain circumstances,
causes the device to cease proper operation. The voltage of the
LEDx pins must not be confused with the supply voltages for the
LED themselves. V
LEDx
is the voltage applied to the anode of the
external LED, whereas the LEDXx pin is the input of the
internal current driver, and the pins are connected to the
cathode of the external LED.
LED DRIVER OPERATION
The LED driver for the ADPD1080/ADPD1081 is a current
sink. The compliance voltage, measured at the driver pin with
respect to ground, required to maintain the programmed LED
current level is a function of the current required. Figure 12
shows the typical compliance voltages required at the various
LED coarse settings. Figure 40 shows the basic schematic of
how the ADPD1080/ADPD1081 connect to an LED through the
LED driver. The Determining the Average Current section and
the Determining C
VLED
section define the requirements for the
bypass capacitor (C
VLED
) and the supply voltages of the LEDs
(V
LEDx
).
ADPD1080/
ADPD1081
LEDXxLGND
V
LEDx
SUPPLY
C
VLED
16110-040
Figure 40. V
LEDx
Supply Schematic
Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.