AD7908BRUZ Analog Devices Inc, AD7908BRUZ Datasheet - Page 11

• Manufacturer Part Number: AD7908BRUZ
• Description: IC ADC 8BIT 8CH 1MSPS 20-TSSOP
• Manufacturer: Analog Devices Inc

Specifications of AD7908BRUZ

• Data Interface: DSP, MICROWIRE™, QSPI™, Serial, SPI™
• Number Of Bits: 8
• Sampling Rate (per Second): 1M
• Number Of Converters: 1
• Power Dissipation (max): 13.5mW
• Voltage Supply Source: Single Supply
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 20-TSSOP (0.173", 4.40mm Width)
• Resolution (bits): 8bit
• Sampling Rate: 1MSPS
• Input Channel Type: Single Ended
• Supply Voltage Range - Analog: 2.7V To 5.25V
• Supply Current: 2.7mA
• Digital Ic Case Style: TSSOP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: EVAL-AD79X8CBZ - BOARD EVALUATION FOR AD79X8
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant

PIN CONFIGURATION AND FUNCTION DESCRIPTIONS
Table 6. Pin Function Descriptions
Pin No.
1
2
3
4, 8, 17, 20
5, 6
7
16 to 9
18
19
Mnemonic
SCLK
DIN
CS
AGND
AV
REF
V
DOUT
V
IN
DRIVE
DD
0 to V
IN
IN
7
Description
Serial Clock. Logic input. SCLK provides the serial clock for accessing data from the part. This clock input is also
used as the clock source for the conversion process of the AD7908/AD7918/AD7928.
Data In. Logic input. Data to be written to the control register of the AD7908/AD7918/AD7928 is provided on
this input and is clocked into the register on the falling edge of SCLK (see the Control Register section).
Chip Select. Active low logic input. This input provides the dual function of initiating conversions on the
AD7908/AD7918/AD7928, and also frames the serial data transfer.
Analog Ground. This is the ground reference point for all analog circuitry on the AD7908/AD7918/AD7928. All
analog input signals and any external reference signal should be referred to this AGND voltage. All AGND pins
should be connected together.
Analog Power Supply Input. The AV
to 2 × REF
Reference Input for the AD7908/AD7918/AD7928. An external reference must be applied to this input. The
voltage range for the external reference is 2.5 V ± 1% for specified performance.
Analog Input 0 through Analog Input 7. These are eight single-ended analog input channels that are
multiplexed into the on-chip track-and-hold. The analog input channel to be converted is selected by using
Address Bit ADD2 through Address Bit ADD0 of the control register. The address bits, in conjunction with the
SEQ and SHADOW bits, allow the sequencer to be programmed. The input range for all input channels can
extend from 0 V to REF
input channels must be connected to AGND to avoid noise pickup.
Data Out. Logic output. The conversion result from the AD7908/AD7918/AD7928 is provided on this output as
a serial data stream. The bits are clocked out on the falling edge of the SCLK input. The data stream from the
AD7908 consists of one leading zero, three address bits indicating which channel the conversion result
corresponds to, followed by the eight bits of conversion data, followed by four trailing zeros, provided MSB
first; the data stream from the AD7918 consists of one leading zero, three address bits indicating which
channel the conversion result corresponds to, followed by the 10 bits of conversion data, followed by two
trailing zeros, also provided MSB first; the data stream from the AD7928 consists of one leading zero, three
address bits indicating which channel the conversion result corresponds to, followed by the 12 bits of
conversion data, provided MSB first. The output coding can be selected as straight binary or twos complement
via the CODING bit in the control register.
Logic Power Supply Input. The voltage supplied at this pin determines at what voltage the serial interface of
the AD7908/AD7918/AD7928 operates.
IN
range, AV
DD
IN
AGND
AGND
REF
SCLK
AV
AV
should be from 4.75 V to 5.25 V.
or 0 V to 2 × REF
V
V
DIN
CS
IN
IN
DD
DD
IN
7
6
10
Figure 3. Pin Configuration
1
2
3
4
5
6
7
8
9
Rev. B | Page 11 of 28
(Not to Scale)
AD7908/
AD7918/
AD7928
TOP VIEW
DD
range for the AD7908/AD7918/AD7928 is from 2.7 V to 5.25 V. For the 0 V
IN
as selected via the RANGE bit in the control register. Any unused
20
19
18
17
16
15
14
13
12
11
AGND
V
DOUT
AGND
V
V
V
V
V
V
DRIVE
IN
IN
IN
IN
IN
IN
0
1
2
3
4
5
AD7908/AD7918/AD7928