AD7417 AD [Analog Devices], AD7417 Datasheet - Page 11

• Manufacturer Part Number: AD7417
• Description: 10-Bit Digital Temperature Sensor (AD7416) and Single/Four-Channel ADC (AD7417/AD7418)
• Manufacturer: AD [Analog Devices]

CONFIGURATION REGISTER (ADDRESS 01h)
The Configuration Register is an 8-bit, read/write register that
is used to set the operating modes of the AD7416/AD7417/
AD7418. Bits D7 to D5 control the channel selection as
outlined in Table VI. These bits should always be 0, 0, 0 for
the AD7416. Bits D4 and D3 are used to set the length of the
fault queue. D2 sets the sense of the OTI output. D1 selects
the comparator or interrupt mode of operation, and D0 = 1
selects the shutdown mode (Default D0 = 0).
D7
The AD7416 contains a temperature-only channel, the
AD7417 has four analog input channels and a temperature
channel, and the AD7418 has two channels, a temperature
channel, and an analog input channel. The temperature chan-
nel address for all parts is the same, CH0. The address for the
analog input channel on the AD7418 is CH4. Table VI outlines
the channel selection on the parts, while Table VII shows the
fault queue settings. D1 and D2 are explained in the OTI Out-
put section.
D7
0
0
0
0
1
T
The T
nine MSBs store the T
mat equivalent to the nine MSBs of the Temperature Value
Register. Bits 6 to 0 are unused.
T
The T
whose nine MSBs store the T
format equivalent to the nine MSBs of the Temperature Value
Register. Bits 6 to 0 are unused.
D15
MSB B7
REV. G
HYST
OTI
Channel
Selection
SETPOINT REGISTER (ADDRESS 03h)
HYST
OTI
SETPOINT REGISTER (ADDRESS 02h)
D6
D6
0
0
1
1
0
D14
D4
0
0
1
1
Setpoint Register is a 16-bit, read/write register
Setpoint Register is a 16-bit, read/write register whose
D5
Table V. Configuration Register
D13
B6
Table VII. Fault Queue Settings
D5
0
1
0
1
0
Table VIII. Setpoint Registers
Table VI. Channel Selection
D4
D3
0
1
0
1
Fault
Queue
HYST
D12
B5
Channel Selection
Temperature Sensor (All Parts)
A
A
A
A
D3
IN1
IN2
IN3
IN4
setpoint in twos complement for-
OTI
D11
B4
(AD7417 Only)
(AD7417 Only)
(AD7417 Only)
(AD7417) and A
Number of Faults
1 (Power-Up Default)
2
4
6
setpoint in twos complement
D2
OTI
Polarity
D10
B3
D9
B2
D1
Cmp/
Int
IN
(AD7418)
D8
B1
D0
Shut-
down
LSB
D7
–11–
ADC VALUE REGISTER (ADDRESS 04h)
The ADC Value Register is a 16-bit, read-only register whose
10 MSBs store the value produced by the ADC in binary for-
mat. Bits 5 to 0 are unused. Table IX shows the ADC Value
Register with 10 MSBs containing the ADC conversion request.
D15
MSB B8
ADC Transfer Function
The designed code transitions occur at successive integer LSB
values (i.e., 1 LSB, 2 LSB, and so on). The LSB size = VREF/
1024. The ideal transfer function characteristic for the AD7417
and AD7418 ADC is shown in Figure 7.
CONFIG2 REGISTER (ADDRESS 05h)
A second configuration register is included in the AD7417/
AD7418 for the functionality of the CONVST pin. It is an 8-bit
register with Bits D5 to D0 being left at 0. Bit D7 determines
whether the AD7417/AD7418 should be operated in its default
mode (D7 = 0), performing conversions every 355 µs or in its
CONVST pin mode (D7 = 1), where conversions will start only
when the CONVST pin is used. Bit 6 contains the Test 1 Bit.
When this bit is 0, the I
disables the filters.
D7
Conversion Mode
SERIAL BUS INTERFACE
Control of the AD7416/AD7417/AD7418 is carried out via the
I
connected to this bus as a slave device, under the control of a
master device, e.g., the processor.
SERIAL BUS ADDRESS
As with all I
have a 7-bit serial address. The four MSBs of this address for the
AD7416 are set to 1001; the AD7417 are set to 0101, while the
three LSBs can be set by the user by connecting the A2 to A0
pins to either V
to eight AD7416/AD7417s can be connected to a single serial bus,
2
C compatible serial bus. The AD7416/AD7417/AD7418 is
Figure 7. Ideal Transfer Function Characteristic
for the AD7417/AD7418
D14 D13 D12 D11 D10
2
C compatible devices, the AD7416/AD7417/AD7418
111...111
111...110
111...000
011...111
000...010
000...001
000...000
B7
DD
Table IX. ADC Value Register
Table X. CONFIG2 Register
or GND. By giving them different addresses, up
0V 1/2LSB
AD7416/AD7417/AD7418
B6
D6
Test 1 0
2
C filters are enabled (default). A 1
B5
D5
ANALOG INPUT
B4
D4
0
1LSB = V REF/1024
+VREF – 1LSB
D9
B3
D3
0
D8
B2
D2
0
D7
B1
D1
0
D6
LSB
D0
0