MAX1359B Maxim Integrated Products, MAX1359B Datasheet - Page 39

• Manufacturer Part Number: MAX1359B
• Description: Data-Acquisition System
• Manufacturer: Maxim Integrated Products

DataSheet.in
REF_SDC Register (Power-On State: 0000 0000)
The REF_SDC register contains bits to control the refer-
ence voltage and signal-detect comparator.
REFV<1:0>: Reference buffer voltage gain and enable
bits. Enables the output buffer, sets the gain and the
voltage at the REF pin as shown in Table 10. Power-on
state is off to enable an external reference to drive the
REF pin without contention.
AOFF: ADC and DAC/op-amp power-off bit. This bit pro-
vides a method for turning off several analog functions
with a single write. Setting AOFF = 1 deasserts the
ADCE in the ADC register and DAE/OP3E, DBE/OP2E,
and OP1E bits in the DACA_OP and DACB_OP regis-
ters, powering down these analog blocks. Setting AOFF
= 0 has no effect. The AON bit has priority when both
AON and AOFF bits are asserted.
Most of the analog functions can be disabled with a
single write to the REF_SDC register by using AOFF,
REFV<1:0>, and SDCE.
Table 10. Setting the Reference Output
Voltage
BUFFER GAIN (V/V)
UPIOs, RTC, Voltage Monitors, and Temp Sensor
16-Bit, Data-Acquisition System with ADC, DAC,
REFERENCE
REFV1
MSB
Disabled
1.638
1.0
2.0
______________________________________________________________________________________
REFV0
Impedance at REF)
REF OUTPUT
VOLTAGE (V)
Off (High
2.048
1.25
2.5
AOFF
REFV1
0
0
1
1
REFV0
AON
0
1
0
1
AON: ADC and DAC/op-amp power-on bit. This bit
provides a method of turning on several analog func-
tions with a single write. Setting AON = 1 asserts the
ADCE bit in the ADC register and DAE/OP3E,
DBE/OP2E, and OP1E bits in the DACA_OP and
DACB_OP registers, powering up these blocks. Setting
AON = 0 has no effect. The AON bit has priority when
both AON and AOFF bits are asserted.
Most of the analog functions can be enabled with a sin-
gle write to the REF_SDC register using AON,
REFV<1:0>, and SDCE.
SDCE: Signal-detect comparator power-enable bit. Set
SDCE = 1 to power up the signal-detect comparator
and set SDCE = 0 to power down the signal-detect
comparator. The ADCE bit in the ADC register must be
set to 1 to use the signal-detect comparator.
TSEL<2:0>: Threshold-select bits. These bits select the
threshold for the signal-detect comparator as shown in
Table 11.
Table 11. Setting the Signal-Detect
Comparator Threshold
X = Don’t care.
THRESHOLD (mV)
SDCE
NOMINAL
100
150
200
50
0
TSEL2
TSEL2
0
1
1
1
1
TSEL1
TSEL1
X
0
0
1
1
TSEL0
LSB
TSEL0
X
0
1
0
1
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