AD7416/AD7417/AD7418
CONFIGURATION REGISTER (ADDRESS 01h)
ADC VALUE REGISTER (ADDRESS 04h)
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).
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.
Table IX. ADC Value Register
D15 D14 D13 D12 D11 D10 D9 D8 D7 D6
MSB B8
B7
B6
B5
B4
B3 B2 B1 LSB
Table V. Configuration Register
ADC Transfer Function
D7
D6 D5
Channel
Selection
D4
Fault
Queue
D3
D2
D1
D0
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.
OTI
Polarity
Cmp/
Int
Shut-
down
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.
111...111
111...110
111...000
1LSB =VREF/1024
011...111
000...010
000...001
000...000
Table VI. Channel Selection
0V 1/2LSB
+VREF – 1LSB
ANALOG INPUT
D7
D6
D5
Channel Selection
Figure 7. Ideal Transfer Function Characteristic
for the AD7417/AD7418
0
0
0
0
1
0
0
1
1
0
0
1
0
1
0
Temperature Sensor (All Parts)
A
IN1 (AD7417 Only)
AIN2 (AD7417 Only)
IN3 (AD7417 Only)
AIN4 (AD7417) and AIN (AD7418)
CONFIG2 REGISTER (ADDRESS 05h)
A
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 I2C filters are enabled (default). A 1
disables the filters.
Table VII. Fault Queue Settings
D4
D3
Number of Faults
0
0
1
1
0
1
0
1
1 (Power-Up Default)
2
4
6
Table X. CONFIG2 Register
D7
D6
D5 D4 D3 D2 D1 D0
THYST SETPOINT REGISTER (ADDRESS 02h)
The THYST Setpoint Register is a 16-bit, read/write register whose
nine MSBs store the THYST setpoint in twos complement for-
mat equivalent to the nine MSBs of the Temperature Value
Register. Bits 6 to 0 are unused.
Conversion Mode Test 1
0
0
0
0
0
0
SERIAL BUS INTERFACE
Control of the AD7416/AD7417/AD7418 is carried out via the
I2C compatible serial bus. The AD7416/AD7417/AD7418 is
connected to this bus as a slave device, under the control of a
master device, e.g., the processor.
TOTI SETPOINT REGISTER (ADDRESS 03h)
The TOTI Setpoint Register is a 16-bit, read/write register
whose nine MSBs store the TOTI setpoint in twos complement
format equivalent to the nine MSBs of the Temperature Value
Register. Bits 6 to 0 are unused.
SERIAL BUS ADDRESS
As with all I2C compatible devices, the AD7416/AD7417/AD7418
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 VDD or GND. By giving them different addresses, up
to eight AD7416/AD7417s can be connected to a single serial bus,
Table VIII. Setpoint Registers
D15 D14 D13 D12
D11 D10 D9
B4 B3 B2
D8
D7
MSB B7
B6
B5
B1 LSB
REV. G
–11–
ADI [ ADI ]
