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THS1408-EP_14 Datasheet, PDF (15/28 Pages) Texas Instruments – 14-BIT, 3/8 MSPS DSP-COMPATIBLE ANALOG-TO-DIGITAL CONVERTER WITH INTERNAL REFERENCE AND PGA | |||
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THS1408-EP
14-BIT, 3/8 MSPS DSP-COMPATIBLE ANALOG-TO-DIGITAL CONVERTER
WITH INTERNAL REFERENCE AND PGA
SGLS129B â JULY 2002 â REVISED FEBRUARY 2010
PRINCIPLES OF OPERATION
registers
The device contains several registers. The A register is selected by the values of bits A1 and A0:
A1
A0
Register
0
0
Conversion result
0
1
PGA
1
0
Offset
1
1
Control
Tables 1 and 2 describe how to read the conversion results and how to configure the data converter. The default
values (where applicable) show the state after a power-on reset.
Table 1. Conversion Result Register, Address 0, Read
BIT
D13 D12 D11 D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
Function MSB
...
â¦
â¦
â¦
â¦
â¦
â¦
â¦
â¦
â¦
â¦
â¦
LSB
The output can be configured for twoâs complement or straight binary format (see D11/control register).
The output code is given by:
2s complement:
â8192 at ÎIN = âÎREF
0
at ÎIN = 0
8191 ÎIN = âÎREF â 1 LSB
Straight binary:
0
at ÎIN = âÎREF
8192 at ÎIN = 0
16383 at ÎIN = âÎREF â 1 LSB
1
LSB
+
2DREF
16384
Table 2. PGA Gain Register, Address 1, Read/Write
BIT
D13 D12 D11 D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
Function
X
X
X
X
X
X
X
X
X
X
X
G2
G1
G0
Default
0
0
0
0
0
0
0
0
0
0
0
0
0
0
The PGA gain is determined by writing to G2â0.
Gain (dB) = 1dB Ã G2â0. max = 7dB. The range of G2â0 is 0 to 7.
Table 3. Offset Register, Address 2, Read/Write
BIT
D13 D12 D11 D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
Function
X
X
X
X
X
X
MSB
â¦
â¦
â¦
â¦
â¦
â¦
LSB
Default
0
0
0
0
0
0
0
0
0
0
0
0
0
0
The offset correction range is from â128 to 127 LSB. This value is added to the conversion results from the ADC.
⢠POST OFFICE BOX 655303 DALLAS, TEXAS 75265
15
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