AD5420BCPZ AD [Analog Devices], AD5420BCPZ Datasheet - Page 21

• Manufacturer Part Number: AD5420BCPZ
• Description: Single Channel, 16-Bit, Serial Input, Current Source DAC
• Manufacturer: AD [Analog Devices]

Preliminary Technical Data
DEFAULT CONFIGURATION
On initial power-up of the AD5420, the power-on-reset circuit
ensures that all registers are loaded with zero-code, as such the
default output range is 4mA to 20mA. The current output until
a value is programmed is 0mA. An alternative current range
may be selected via the CONTROL register.
TRANSFER FUNCTION
For the 0 to 20mA, 0 to 24mA and 4 to 20mA current output
ranges the output current expressions are respectively given by;
DATA REGISTER
The DATA register is addressed by setting the control word of the input shift register to 0x01. The data to be written to the DATA register
is entered in positions D15 to D0 as shown in Table 11,
Table 11. Programming the Data Register
MSB
D15
CONTROL REGISTER
The CONTROL register is addressed by setting the control word of the input shift register to 0x55. The data to be written to the
CONTROL register is entered in positions D15 to D0 as shown in Table 12. The CONTROL register functions are shown in Table 13.
Table 12. Programming the CONTROL Register
Table 13. Control Register Functions
Option
REXT
OUTEN
SR CLOCK
SR STEP
SREN
DCEN
R2,R1,R0
MSB
D15
0
D14
D14
Description
Setting this bit selects the external current
setting resistor, Further details in Features
section
Output enable. This bit must be set to enable
the output.
See Features Section. Digital Slew Rate Control
See Features Section. Digital Slew Rate Control
Digital Slew Rate Control enable
Daisychain enable
Output range select. See Table 14
0
D13
REXT
D13
D12
OUTEN
D12
D11
D11
D10
D10
SR CLOCK
Rev. PrD | Page 21 of 29
D9
DATA WORD
D9
D8
D8
where:
D is the decimal equivalent of the code loaded to the DAC.
N is the bit resolution of the DAC.
Table 14. Output Range Options
R2
1
1
1
D7
D7
R1
0
1
1
D6
SR STEP
D6
I
R0
1
0
1
OUT
D5
D5
I
I
OUT
OUT
=
⎡
⎢ ⎣
Output Range Selected
4 to 20 mA Current Range
0 to 20 mA Current Range
0 to 24 mA Current Range
16
D4
=
=
SREN
D4
2
⎡
⎢ ⎣
⎡
⎢ ⎣
mA
N
20
24
2
2
mA
mA
⎤
⎥ ⎦
D3
N
N
×
DCEN
D
D3
⎤
⎥ ⎦
⎤
⎥ ⎦
×
×
+
D2
D
D
4
mA
D2
R2
D1
AD5420
D1
R1
LSB
D0
LSB
D0
R0