Datasheet
Data Sheet AD9255
Rev. C | Page 11 of 44
PIN CONFIGURATIONS AND FUNCTION DESCRIPTIONS
13
14
15
16
17
18
19
20
21
22
23
24
DRVDD
D2
D3
D4
D5
D6
D7
DRVDD
D8
D9
D10
D11
48
47
46
45
44
43
42
41
40
39
38
37
PDWN
RBIAS
VCM
AVDD
LVDS
VIN–
VIN+
LVDS_RS
DNC
DNC
VREF
SENSE
1
2
3
4
5
6
7
8
9
10
11
12
SYNC
CLK+
CLK–
AVDD
AVDD
OEB
DNC
DCO
DNC
DNC
D0 (LSB)
D1
DITHER
AVDD
SVDD
CSB
SCLK/DFS
SDIO/DCS
DRVDD
DNC
OR
D13 (MSB)
D12
35
AVDD36
34
33
32
31
30
29
28
27
26
25
AD9255
PARALLEL
CMOS
TOP VIEW
(Not to Scale)
PIN 1
INDICATOR
NOTES
1. DNC = DO NOT CONNECT.
2. THE EXPOSED THERMAL PAD ON THE BOTTOM OF THE PACKAGE
PROVIDES THE ANALOG GROUND FOR THE INPUT. THIS EXPOSED
PAD MUST BE CONNECTED TO GROUND FOR PROPER OPERATION.
08505-003
Figure 4. LFCSP Parallel CMOS Pin Configuration (Top View)
Table 8. Pin Function Descriptions (Parallel CMOS Mode)
Pin No. Mnemonic Type Description
ADC Power Supplies
13, 20, 29 DRVDD Supply Digital Output Driver Supply (1.8 V Nominal).
4, 5, 34, 36, 45 AVDD Supply Analog Power Supply (1.8 V Nominal).
33 SVDD Supply SPI Input/Output Voltage
7, 9, 10, 28, 39, 40 DNC Do Not Connect.
0 AGND Ground
Analog Ground. The exposed thermal pad on the bottom of the package provides
the analog ground for the input. This exposed pad must be connected to ground for
proper operation.
ADC Analog
42 VIN+ Input Differential Analog Input Pin (+).
43 VIN− Input Differential Analog Input Pin (−).
38
VREF
Input/output
Voltage Reference Input/Output.
37 SENSE Input Voltage Reference Mode Select. See Table 11 for details.
47 RBIAS Input/output External Reference Bias Resistor.
46 VCM Output Common-Mode Level Bias Output for Analog Inputs.
2 CLK+ Input ADC Clock Input—True.
3 CLK− Input ADC Clock Input—Complement.
Digital Input
1 SYNC Input Digital Synchronization Pin. Slave mode only.
Digital Outputs
11 D0 (LSB) Output CMOS Output Data.
12 D1 Output CMOS Output Data.
14 D2 Output CMOS Output Data.
15 D3 Output CMOS Output Data.
16 D4 Output CMOS Output Data.
17 D5 Output CMOS Output Data.
18 D6 Output CMOS Output Data.
19 D7 Output CMOS Output Data.
21
D8
Output
CMOS Output Data.