MAX1065CEUI Maxim Integrated, MAX1065CEUI Datasheet - Page 10

• Manufacturer Part Number: MAX1065CEUI
• Description: Analog to Digital Converters - ADC
• Manufacturer: Maxim Integrated

Specifications of MAX1065CEUI

• Number Of Channels: 1
• Architecture: SAR
• Conversion Rate: 165 KSPs
• Resolution: 14 bit
• Input Type: Single-Ended
• Snr: 84 dB
• Interface Type: Parallel
• Operating Supply Voltage: 2.7 V to 5.25 V, 4.75 V to 5.25 V
• Maximum Power Dissipation: 1026 mW
• Number Of Converters: 1
• Voltage Reference: 4.096 V

While in standby mode, the supply current is reduced
to less than 1mA (typ). The next falling edge of CS with
R/C low causes the MAX1065/MAX1066 to exit standby
mode and begin acquisition. The reference and refer-
ence buffer remain active to allow quick turn-on time.
Standby mode allows significant power savings while
running at the maximum sample rate.
In shutdown mode, the reference and reference buffer
are shut down between conversions. Shutdown mode
reduces supply current to 0.5µA (typ) immediately after
the conversion. The falling edge of CS with R/C low
causes the reference and buffer to wake up and enter
acquisition mode. To achieve 14-bit accuracy, allow
10ms (C
reference to wake up. Increase wakeup time propor-
tionally when using larger values of C
Low-Power, 14-Bit Analog-to-Digital Converters
with Parallel Interface
Figure 4. Equivalent Input Circuit
Figure 5. Selecting Standby Mode
10
AIN
C
BUFFER
SWITCH
3pF
AND
EOC
REF
R/C
______________________________________________________________________________________
CS
REFADJ
TRACK
HOLD
ACQUISITION
REF POWER-
DOWN BIT
AGND
= 0.1µF, C
REF
CAPACITIVE DAC
C
DAC
= 32pF
HOLD
REF
CONVERSION
= 1µF) for the internal
Shutdown Mode
TRACK
R
800Ω
IN
ZERO
REFADJ
Standby Mode
AUTO-ZERO
and C
DATA
OUT
RAIL
REF
.
The internal reference of the MAX1065/MAX1066 is
internally buffered to provide 4.096V (typ) output at
REF. Bypass REF to AGND and REFADJ to AGND with
1µF and 0.1µF respectively. Fine adjustments can be
made to the internal reference voltage by sinking or
sourcing current at REFADJ. The input impedance at
REFADJ is nominally 5kΩ. The internal reference volt-
age is adjustable to ±1.5% with the circuit of Figure 7.
An external reference can be placed at either the input
(REFADJ) or the output (REF) of the MAX1065/
MAX1066’s internal buffer amplifier. When connecting
an external reference to REFADJ, the input impedance
is typically 5kΩ. Using the buffered REFADJ input
makes buffering the external reference unnecessary;
however, the internal buffer output must be bypassed
at REF with a 1µF capacitor.
Connect REFADJ to AV
Directly drive REF using an external reference. During
conversion, the external reference must be able to
drive 100µA of DC load current and have an output
impedance of 10Ω or less. REFADJ’s impedance is typ-
ically 5kΩ. The DC input impedance of REF is 40kΩ
minimum.
For optimal performance, buffer the reference through
an op amp and bypass REF with a 1µF capacitor.
Consider the MAX1065/MAX1066’s equivalent input
noise (80µV
Figure 6. Selecting Shutdown Mode
BUFFER
AND
EOC
REF
R/C
CS
RMS
ACQUISITION
REF POWER-
DOWN BIT
Internal and External Reference
) when choosing a reference.
DD
to disable the internal buffer.
CONVERSION
External Reference
Internal Reference
DATA
OUT