Datasheet
AFE0064
www.ti.com
........................................................................................................................................................................................ SLAS672 –SEPTEMBER 2009
As explained before the device samples the integrator output twice, Reset sample ( SHR) and Signal sample
(SHS).
V
OUTM
= REFM + (V
SHS
– V
SHR
)
V
OUTP
= REFP – (V
SHS
– V
SHR
)
Case 2: (Integrator down mode, INTUPz = 1)
As explained before the device samples the integrator output twice, Reset sample ( SHR) and Signal sample
(SHS).
V
OUTM
= REFP + (V
SHS
– V
SHR
)
V
OUTP
= REFM – (V
SHS
– V
SHR
)
The differential output from the AFE0064 rejects common-mode noise from the board helping to maximize noise
performance of the system. The following table provides details of integrator feedback ranges, feedback
capacitor, and corresponding AFE0064 output at zero and full scale input charge.
Table 1. AFE0064 Range Selection to Device Analog Output Mapping
REFP 2.25
REFP-REFM 1.4
REFM 0.85
INTEGRATE UP MODE INTEGRATE DOWN MODE
(INTUPz=0), e– counting (INTUPz=1), hole+ counting
At 0 charge I/p At FS charge I/p At 0 charge I/p At FS charge I/p
Typical FS Int FB Cap= (Qr)/
Range Charge Range (REFP-REFM) OUTP OUTM OUTP OUTM OUTP OUTM OUTP OUTM
(Qr) pC … pF
0 0.13 0.0929
1 0.25 0.1786
2 0.5 0.3571
3 1.2 0.8571
2.25 0.85 0.85 2.25 0.85 2.25 2.25 0.85
4 2.4 1.7143
5 4.8 3.4286
6 7.2 5.1429
7 9.6 6.8571
The following section provides detailed timing of data read. There are two output drivers. Data for channel
number 63 to 32 is available on output driver 1 and data for channel number 31 to 0 is available on output driver
0. Data from two drivers can be available simultaneously or sequentially depending on the status of pin
SMT_MD.
Figure 5. Device Data Read in Sequential Mode (SMT_MD = 0)
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