ADUC7032_15 Datasheet, PDF (47/128 Pages) Analog Devices – MicroConverter Integrated, Precision Battery Sensor

Preliminary Technical Data
ADC GROUND SWITCH
The ADuC7032 features an integrated ground switch pin,
GND_SW located on Pin15. This switch allows the user to
dynamically disconnect ground from external devices. It allows
either a direct connection to ground, or a connection to ground
via a 20kΩ, this additional resistor may be used to reduce the
number of external components required for an NTC circuit.
The ground switch feature may be used for reducing power
consumption on application specific boards..
An example application is shown in Figure 17. This diagram
shows an external NTC used in two modes, one using the
internal 20kΩ resistor, and the second showing a direct
connection to ground, via the GND_SW. ADCCFG[7] controls
the connection of the ground switch to ground and
ADCMDE[6] controls the GND_SW resistance.
ADuC7032
The possible combinations are shown in Table 18.
Table 18 : GND_SW Configuration
ADCCFG[7] ADCMDE[6]
GND_SW
0
0
Floating
0
1
Floating
1
0
Direct connection to Ground
1
1
Connected to ground via 20kΩ
resistor
R_REF
NTC
REG_AVDD
VTEMP _NTC
REG_AVDD
VTEMP
20kΩ
Figure 17 : Example External Temperature Sensor Circuits
GND_SW
ADCCFG[7]
20kΩ
ADCMDE[6]
Figure 18: Internal Ground Switch Configuration
Rev. PrD | Page 47 of 128