MAX1254AEUE+ Maxim Integrated, MAX1254AEUE+ Datasheet - Page 11

• Manufacturer Part Number: MAX1254AEUE+
• Description: Analog to Digital Converters - ADC
• Manufacturer: Maxim Integrated

Specifications of MAX1254AEUE+

• Number Of Channels: 10
• Architecture: SAR
• Conversion Rate: 94 KSPs
• Resolution: 12 bit
• Input Type: Single-Ended/Differential
• Interface Type: Serial
• Operating Supply Voltage: 4.5 V to 5.5 V
• Number Of Converters: 1
• Voltage Reference: Internal 4.096 V or External

During the acquisition interval, IN+ and IN- charge both
a positive (CHOLDP) and a negative (CHOLDN) sam-
pling capacitor. After completing the acquisition inter-
val, the T/H switches open, storing an accurate sample
of the differential voltage between IN+ and IN-. This
charge is then transferred to the ADC and converted.
Finally, the conversion result is transferred to the cur-
rent data register.
Temperature conversions require 46µs (typ) and mea-
sure the difference between two sequential voltage
measurements (see the Temperature Measurement
section for a detailed description).
The T/H acquisition interval begins with the rising edge
of CS (for manually triggered conversions) and is inter-
nally timed to 1.5µs (typ). The accuracy of the input sig-
nal sample is a function of the input signal’s source
impedance and the T/H’s capacitance. In order to
achieve adequate settling of the T/H, limit the signal
source impedance to a maximum of 1kΩ.
Figure 3. Simplified Alarm Block Diagram of the MAX1253/MAX1254
with Internal Temperature Sensor and V
Stand-Alone, 10-Channel, 12-Bit System Monitors
Fully Differential Track/Hold (T/H)
AIN0
AIN1
AIN2
AIN3
AIN4
AIN5
AIN6
AIN7
V
DD
______________________________________________________________________________________
SENSE
TEMP
MUX
ADC WITH T/H
12-BIT
The ADC’s input tracking circuitry has a 1MHz small-
signal bandwidth. To avoid high-frequency signals
aliasing into the frequency band of interest, anti-alias
prefiltering of the input signals is recommended.
Internal protection diodes, which clamp the analog
inputs to V
swing from (GND - 0.3V) to (V
age. However, for accurate conversions near full scale,
the inputs must not exceed V
be lower than GND by 50mV. If the analog input range
must exceed 50mV beyond the supplies, limit the input
current.
The MAX1253/MAX1254 use a fully differential ADC for
all conversions. Through the input configuration regis-
ter, the analog inputs can be configured for either dif-
ferential or single-ended conversions. When sampling
signal sources close to the MAX1253/MAX1254, single-
ended conversion is generally sufficient. Single-ended
conversions use only one analog input per signal
source, internally referenced to GND.
LOWER THRESHOLD
UPPER THRESHOLD
INPUT REGISTERS
CONFIGURATION/
# FAULT CYCLES
CURRENT DATA
CONVERSION
REGISTERS
SCAN AND
CONTROL
AVERAGE
STATUS
DD
and GND, allow the channel input pins to
INTERFACE
COMPARATOR
SERIAL
DIGITAL
Analog Input Protection
Single Ended/Differential
DD
DD
DD
by more than 50mV or
Input Bandwidth
+ 0.3V) without dam-
DIN
DOUT
SCLK
CS
INT
Monitor
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