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ADC128D818
January 10, 2011
12-Bit, 8-Channel, ADC System Monitor with Temperature
Sensor, Internal/External Reference, and I
2
C Interface
1.0 General Description
The ADC128D818 I
2
C™ system monitor is designed for max-
imum flexibility. The system monitor can be configured for
single-ended and/or pseudo-differential inputs. An on-board
temperature sensor, combined with WATCHDOG window
comparators, and an interrupt output pin, INT
, allow easy
monitoring and out-of-range alarms for every channel. A high
performance internal reference is also available to provide for
a complete solution in the most difficult operating conditions.
The ADC128D818’s 12-bit delta-sigma ADC supports Stan-
dard Mode (Sm, 100 kbits/s) and Fast Mode (Fm, 400kbits/s)
I
2
C interfaces. The ADC128D818 includes a sequencer to
control channel conversions and stores all converted results
in independent registers for easy microprocessor retrieval.
Unused channels can be shut down independently to con-
serve power.
The ADC can use either an internal 2.56V reference or a vari-
able external reference. An analog filter is included on the
I
2
C digital control lines to provide improved noise immunity.
The device also includes a TIMEOUT reset function on SDA
and SCL to prevent I
2
C bus lock-up.
The ADC128D818 operates from +3.0 to +5.5V power supply
voltage range, –40°C to 125°C temperature range, and the
device is available in a 16-pin TSSOP package.
2.0 Applications
■
Communications Infrastructure
■
Thermal / Hardware Server Monitors
■
System Monitors
■
Industrial and Medical Systems
■
Electronic Test Equipment and Instrumentation
■
Power Supply Monitoring / Supervision
3.0 Features
■
12-bit Resolution Delta-Sigma ADC
■
Local Temperature Sensing
■
Configurable Single-Ended and/or Pseudo-Diff. Inputs
■
+2.56V Internal VREF or Variable External VREF
■
WATCHDOG Window Comparators with Status and Mask
Registers of All Measured Values
■
Independent Registers for Storing Measured Values
■
INT
Output Notifies Microprocessor of Error Event
■
I
2
C Serial Bus Interface Compatibility
■
9 Selectable Addresses
■
TIMEOUT Reset Function to Prevent I
2
C Bus Lock-Up
■
Individual Channel Shutdown to Limit Power Consumption
■
Deep Shutdown Mode to Minimize Power Consumption
■
TSSOP 16-Lead Package
4.0 Key Specifications
■ ADC Resolution 12-bit
■ Supply Voltage Range +3.0V to +5.5V
■ Total Unadjusted Error –0.45/+0.2%
■ Integral Non-Linearity ±1LSb
■ Differential Non-Linearity ±1LSb
■ Operating Current 0.56 mA
■ Deep Shutdown Current 10 µA
■ Temperature Resolution 0.5°C/LSb
■ Temp. Accuracy (–40°C to 125°C) ± 3°C
■ Temp. Accuracy (–25°C to 100°C) ± 2°C
5.0 Typical Application
30096301
I
2
C® is a registered trademark of the Philips Corporation.
© 2011 National Semiconductor Corporation 300963 www.national.com
ADC128D818 12-Bit, 8-Channel, ADC System Monitor with Temperature Sensor, Internal/
External Reference, and I
2
C Interface
