XE8801AMI027LF Semtech, XE8801AMI027LF Datasheet - Page 96

• Manufacturer Part Number: XE8801AMI027LF
• Description: IC DAS 16BIT FLASH 8K MTP 44LQFP
• Manufacturer: Semtech

Specifications of XE8801AMI027LF

• Applications: Sensing Machine
• Core Processor: RISC
• Program Memory Type: FLASH (22 kB)
• Controller Series: XE8000
• Ram Size: 512 x 8
• Interface: UART, USRT
• Number Of I /o: 24
• Voltage - Supply: 2.4 V ~ 5.5 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 44-LQFP
• For Use With: XE8000MP - PROG BOARD AND PROSTART2 CARD
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

16.6.3
The second PGA has a finer gain and offset tuning capability, as shown in Table 16-15 and Table 16-16. The voltage
V
where GD
PGA2_GAIN[1:0] and PGA2_OFFSET[3:0].
As shown in equation 6, the offset correction is directly proportional to the reference voltage. All drifts and
perturbations on the reference voltage will affect the precision of the offset compensation.
16.6.4
The finest gain and offset tuning is performed with the third and last PGA stage, according to the coding of Table
16-17 and Table 16-18. The output of PGA3 is also the input of the ADC. Thus, similarly to PGA2, we find that the
voltage entering the ADC is given by:
where GD
PGA3_GAIN[6:0] and PGA3_OFFSET[6:0] . To remain within the signal compliance of the PGA stages, the
condition:
must be verified.
As shown in equation 7, the offset correction is directly proportional to the reference voltage. All drifts and
perturbations on the reference voltage will affect the precision of the offset compensation.
Finally, combining equations Eq. 5 to Eq. 7 for the three PGA stages, the input voltage V
to V
where the total PGA gain is defined as:
and the total PGA offset is:
© Semtech 2005
D2
at the output of PGA2 is given by:
IN
by:
V
V
V
V
GD
GDoff
D
IN
D
IN
2
1
2
PGA2
PGA3
,
3
,
,
TOT
ADC
ADC
and GDoff
V
=
and GDoff
D
GD
TOT
2
=
=
=
<
GD
GD
GD
2
=
V
⋅
GDoff
V
DD
3
3
TOT
D
⋅
⋅
1
V
GD
2
−
⋅
D
(V)
are respectively the gain and offset of PGA2 (in V/V). These are controlled with the words
V
GDoff
2
3
3
2
IN
−
+
⋅
are respectively the gain and offset of PGA3 (in V/V). The control words are
GD
GDoff
−
GD
GDoff
2
1
3
⋅
V
⋅
3
GDoff
REF
⋅
TOT
V
REF
⋅
V
2
(V)
(V/V)
REF
(V)
(V)
(V/V)
16-11
(Eq. 6)
(Eq. 7)
(Eq. 8)
(Eq. 9)
(Eq. 10)
(Eq. 11)
XE8801A – SX8801R
IN,ADC
of the ADC is related
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