sx8725 Semtech Corporation, sx8725 Datasheet - Page 27

• Manufacturer Part Number: sx8725
• Description: Sx8725 Zoomingadc? For Pressure And Temperature Sensing
• Manufacturer: Semtech Corporation

ADVANCED COMMUNICATIONS & SENSING
The equivalent LSB size at the input of the PGA chain is:
Notice that the input voltage V
to remain within the ADC input range.
Power Saving Modes
During low-speed operation, the bias current in the PGAs and ADC can be programmed to save power using
the control words IB_AMP_PGA[1:0] and IB_AMP_ADC[1:0] (see Table 17). If the system is idle, the PGAs and
ADC can even be disabled, thus, reducing power consumption to its minimum. This can considerably improve
battery life.
V1.5 © 2007 Semtech Corp.
IB_AMP_ADC[1:0]
(RegACCfg1[7:6])
00
01
11
x
Table 17 - ADC & PGA Power Saving Modes and Maximum Sampling Frequency
IB_AMP_PGA[1:0]
(RegACCfg1[5:4])
IN,ADC
V
IN
00
01
11
x
,
ADC
of the ADC must satisfy the condition:
LSB
ZoomingADC™ for Pressure and Temperature Sensing
1
2
V
2
1
REFP
ADC Bias Current
n
Equation 19
Equation 20
V
GD
REF
1/2 IADC
1/4 IADC
V
27
IADC
REFN
TOT
,
x
ADC
OSR
OSR
OSR
OSR
1
1
PGA Bias Current
(V)
1/2 IPGA
1/4 IPGA
IPGA
x
(V)
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Max. f
125
250
500
125
250
500
SX8725
s
[kHz]