AD7655AST Analog Devices Inc, AD7655AST Datasheet - Page 8

• Manufacturer Part Number: AD7655AST
• Description: IC ADC 16BIT 1MSPS QUAD 48-LQFP
• Manufacturer: Analog Devices Inc
• Series: PulSAR®r

Specifications of AD7655AST

• Rohs Status: RoHS non-compliant
• Number Of Bits: 16
• Sampling Rate (per Second): 1M
• Data Interface: Serial, Parallel
• Number Of Converters: 1
• Power Dissipation (max): 135mW
• Voltage Supply Source: Analog and Digital
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 48-LQFP
• For Use With: EVAL-AD7655CBZ - BOARD EVALUATION FOR AD7655

AD7655
PIN CONFIGURATION AND FUNCTION DESCRIPTIONS
Table 6. Pin Function Descriptions
Pin No.
1, 47, 48
2
3
4
5
6, 20
7
8
9, 10
11, 12
13
14
Mnemonic
AGND
AVDD
A0
BYTESWAP
A/B
DGND
IMPULSE
SER/PAR
D[0:1]
D[2:3] or
DIVSCLK[0:1]
D[4]
or EXT/INT
D[5]
or INVSYNC
Type
P
P
DI
DI
DI
P
DI
DI
DO
DI/O
DI/O
DI/O
1
Description
Analog Power Ground Pin.
Input Analog Power Pin. Nominally 5 V.
Multiplexer Select. When LOW, the analog inputs INA1 and INB1 are sampled simultaneously, then
converted. When HIGH, the analog inputs INA2 and INB2 are sampled simultaneously, then converted.
Parallel Mode Selection (8 Bit, 16 Bit). When LOW, the LSB is output on D[7:0] and the MSB is output on
D[15:8]. When HIGH, the LSB is output on D[15:8] and the MSB is output on D[7:0].
Data Channel Selection. In parallel mode, when LOW, the data from Channel B is read. When HIGH,
the data from Channel A is read. In serial mode, when HIGH, Channel A is output first followed by
Channel B. When LOW, Channel B is output first followed by Channel A.
Digital Power Ground.
Mode Selection. When HIGH, this input selects a reduced power mode. In this mode, the power
dissipation is approximately proportional to the sampling rate.
Serial/Parallel Selection Input. When LOW, the parallel port is selected; when HIGH, the serial interface
mode is selected and some bits of the DATA bus are used as a serial port.
Bit 0 and Bit 1 of the Parallel Port Data Output Bus. When SER/PAR is HIGH, these outputs are in high
impedance.
When SER/PAR is LOW, these outputs are used as Bit 2 and Bit 3 of the Parallel Port Data Output Bus.
When SER/PAR is HIGH, EXT/INT is LOW, and RDC/SDIN is LOW, which is the serial master read after
convert mode. These inputs, part of the serial port, are used to slow down the internal serial clock that
clocks the data output. In the other serial modes, these inputs are not used.
When SER/PAR is LOW, this output is used as Bit 4 of the Parallel Port Data Output Bus.
When SER/PAR is HIGH, this input, part of the serial port, is used as a digital select input for choosing
the internal or an external data clock called, respectively, master and slave mode. With EXT/INT tied
LOW, the internal clock is selected on SCLK output. With EXT/INT set to a logic HIGH, output data is
synchronized to an external clock signal connected to the SCLK input.
When SER/PAR is LOW, this output is used as Bit 5 of the Parallel Port Data Output Bus.
When SER/PAR is HIGH, this input, part of the serial port, is used to select the active state of the SYNC
signal in Master modes. When LOW, SYNC is active HIGH. When HIGH, SYNC is active LOW.
D2/DIVSCLK[0]
D3/DIVSCLK[1]
BYTESWAP
IMPULSE
SER/PAR
Figure 4. 48-Lead LQFP (ST-48) and 48-Lead LFCSP (CP-48)
AGND
DGND
AVDD
A/B
A0
D0
D1
10
11
12
1
2
3
4
5
6
7
8
9
48 47 46 45 44 43 42 41 40 39 38 37
13 14 15 16 17 18 19 20 21 22 23 24
PIN 1
Rev. B | Page 8 of 28
(Not to Scale)
AD7655
TOP VIEW
36
35
34
33
32
31
30
29
28
27
26
25
DVDD
CNVST
PD
RESET
CS
RD
EOC
BUSY
D15
D14
D13
D12