AD7934-6 Analog Devices, AD7934-6 Datasheet - Page 13

• Manufacturer Part Number: AD7934-6
• Description: 4-Channel, 625 kSPS, 12-Bit Parallel ADC with a Sequencer
• Manufacturer: Analog Devices

Specifications of AD7934-6

• Resolution (bits): 12bit
• # Chan: 4
• Sample Rate: 625kSPS
• Interface: Par
• Analog Input Type: Diff-Uni,SE-Uni
• Ain Range: Uni (Vref),Uni (Vref) x 2
• Adc Architecture: SAR
• Pkg Type: SOP

CONTROL REGISTER
The control register on the AD7934-6 is a 12-bit, write-only
register. Data is written to this register using the CS and WR
pins. The control register is shown in Table 6 and the functions
Table 6. Control Register Bits
MSB
DB11
PM1
Table 7. Control Register Bit Function Description
Bit No.
11, 10
9
8
7
6, 5
4, 3
2
1
0
Table 8. Power Mode Selection Using the Power Management Bits in the Control Register
PM1
0
0
1
1
Table 9. Analog Input Type Selection
Channel Address
ADD1
0
0
1
1
PM0
0
1
0
1
ADD0
0
1
0
1
Mnemonic
PM1, PM0
CODING
REF
ZERO
ADD1,
ADD0
MODE1,
MODE0
SEQ1
SEQ0
RANGE
Mode
Normal Mode
Autoshutdown
Autostandby
Full Shutdown
DB10
PM0
MODE0 = 0, MODE1 = 0
Four Single-Ended
Input Channels
V
V
V
V
V
Description
Power management bits used to select the power mode of operation. The user can choose between normal mode
and various power-down modes of operation, as shown in Table 8.
Selects the output coding of the conversion result. If set to 0, the output coding is straight (natural) binary. If set to
1, the output coding is twos complement.
Selects whether the internal or external reference is used to perform the conversion. If this bit is Logic 0, an
external reference should be applied to the V
Reference section.
Not used. This bit should always be set to Logic 0.
Two address bits that either select which analog input channel is to be converted in the next conversion, if the
sequencer is not used, or select the final channel in a consecutive sequence when the sequencer is used, as
described in Table 10. The selected input channel is decoded as shown in Table 9.
Two mode pins that select the type of analog input on the four V
inputs, two fully differential inputs, or two pseudo differential inputs. See Table 9.
Used in conjunction with the SEQ0 bit to control the sequencer function. See Table 10.
Used in conjunction with the SEQ1 bit to control the sequencer function. See Table 10.
Selects the analog input range of the AD7934-6. If set to 0, the analog input range extends from 0 V to V
is set to 1, the analog input range extends from 0 V to 2 × V
5.25 V if a 2.5 V reference is used; otherwise, care must be taken to ensure that the analog input remains within
the supply rails. See the Analog Input Configurations section for more information.
IN
IN
IN
IN
IN+
DB9
CODING
0
1
2
3
Description
When operating in normal mode, all circuitry is fully powered up at all times.
When operating in autoshutdown mode, the AD7934-6 enters full shutdown mode at the end of each
conversion. In this mode, all circuitry is powered down.
When the AD7934-6 enters this mode, the reference remains fully powered, the reference buffer is partially
powered down, and all other circuitry is fully powered down. This mode is similar to autoshutdown mode,
but it allows the part to power up in 7 μs (or 600 ns if an external reference is used). See the Power Modes
of Operation section for more information.
When the AD7934-6 enters this mode, all circuitry is powered down. The information in the control register
is retained.
V
AGND
AGND
AGND
AGND
IN−
DB8
REF
DB7
ZERO
MODE0 = 0, MODE1 = 1
Two Fully Differential
Input Channels
V
V
V
V
V
IN
IN
IN
IN
IN+
0
1
2
3
DB6
ADD1
Rev. B | Page 13 of 28
V
V
V
V
V
IN
IN
IN
IN
IN−
1
0
3
2
REF
DB5
ADD0
pin. If this bit is Logic 1, the internal reference is selected. See the
of the bits are described in Table 7. At power-up, the default bit
settings in the control register are all 0s.
MODE0 = 1, MODE1 = 0
Two Pseudo Differential
Input Channels
V
V
V
V
V
DB4
MODE1
IN
IN
IN
IN
IN+
REF
0
1
2
3
. When this range is selected, V
IN
pins. The AD7934-6 has four single-ended
V
V
V
V
V
DB3
MODE0
IN
IN
IN
IN
IN−
1
0
3
2
DB2
SEQ1
MODE0 = 1, MODE1 = 1
Not Used
DD
must be 4.75 V to
DB1
SEQ0
AD7934-6
REF
LSB
DB0
RANGE
. If it