MAX1359B Maxim Integrated Products, MAX1359B Datasheet - Page 27

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

DataSheet.in
An internal clock drives the charge-pump clock and
ADC clock. The charge pump delivers a maximum
10mA of current to external devices. The droop and the
ripple depend on the clock frequency (f
32.768kHz / 2), switch resistances (R
and the external capacitors (10µF) along with their
respective ESRs, as shown below.
The MAX1359B provides voltage supervisors to monitor
DV
DV
sponding LDVD status bit when DV
1.8V threshold voltage. When the DV
rises above the threshold during power-up, RESET
deasserts after a nominal 1.5s timeout period to give the
crystal oscillator time to stabilize. Set the threshold hys-
teresis using the HYSE bit of the PS_VMONS register.
See the PS_VMONS Register section for configuring hys-
teresis. There is no separate voltage monitor for AV
but the analog supply is covered by the DV
Figure 7. DV
R
UPIOs, RTC, Voltage Monitors, and Temp Sensor
OUT
16-Bit, Data-Acquisition System with ADC, DAC,
DD
DD
V
RIPPLE
supply voltage. RESET asserts and sets the corre-
and CPOUT. The first supervisor monitors the
=
WDTO
f
CLK F
DD
1
V
=
C
Voltage-Supervisor Block Diagram
DROOP
LSDE
f
CLK CPOUT
+
DV
______________________________________________________________________________________
DD
2
I
C
OUT
R
=
SWITCH
I
OUT OUT
1.8VTH
2.0VTH
R
Voltage Supervisors
+
+
ANALOG
2:1 MUX
2
4
I
OUT
ESR
DD
DD
ESR
C
F
SWITCH
falls below the
supply voltage
1.25V
C
+
DD
CPOUT
ESR
monitor in
C
CLK
= 5Ω),
CMP
LSDE
CPOUT
DD
=
,
HYSE POR
CONTROL
LOGIC
many applications where DV
connected together. Multiple supply applications where
AV
separate external voltage monitor for AV
for a block diagram of the DV
The second voltage monitor tracks the charge-pump
output voltage, CPOUT. If CPOUT falls below the 2.7V
threshold, a corresponding register status bit (LCPD) is
set to flag the condition. The CPOUT monitor output
can also be mapped to the interrupt generator and out-
put on INT. The CPOUT monitor can be used as a 3V
AV
disabled and CPOUT is connected to AV
must be greater or equal to DV
to monitor AV
CPOUT voltage supervisor.
The interrupt generator provides an interrupt to an
external µC. The source of the interrupt is generated by
the status register and can be masked and unmasked
through the IMSK register. CRDY is unmasked by
default and INT is active-high at power-on reset. INT is
programmable as active-high and active-low. Possible
sources include a rising or falling edge of UPIO_, an
RTC alarm, an ADC conversion completion, or the volt-
age-supervisor outputs. The interrupt causes INT to
assert when configured as an interrupt output.
DD
DD
monitor in applications where the charge pump is
and DV
RSTE
DV
DD.
DD
DD
(1.8V) VOLTAGE MONITOR
See Figure 8 for a block diagram of the
are not connected together require a
Interrupt Generator (INT)
DD
DD
DD
and AV
voltage supervisor.
when CPOUT is used
LDVD
DD
DD
. See Figure 7
are externally
RESET
DD
. AV
DD
27