ADC121C02XEB/NOPB National Semiconductor, ADC121C02XEB/NOPB Datasheet - Page 8

• Manufacturer Part Number: ADC121C02XEB/NOPB
• Description: BOARD EVAL FOR ADC121C-21
• Manufacturer: National Semiconductor
• Series: PowerWise®r

Specifications of ADC121C02XEB/NOPB

• Number Of Adc's: 1
• Number Of Bits: 12
• Sampling Rate (per Second): 188.9k
• Data Interface: Serial
• Inputs Per Adc: 1 Single Ended
• Input Range: 0 ~ 5.5 V
• Power (typ) @ Conditions: 3.67mw @ 188.9kSPS
• Voltage Supply Source: Single Supply
• Operating Temperature: -40°C ~ 105°C
• Utilized Ic / Part: ADC121C021,ADC121C027
• Silicon Manufacturer: National
• Silicon Core Number: ADC121C021, ADC121C027
• Kit Application Type: Data Converter
• Application Sub Type: ADC
• Kit Contents: Board
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: ADC121C02XEB

4.6 Automatic Conversion Mode
The Automatic Conversion Mode configures the
ADC to continually perform conversions without
receiving
controller.
value into the Cycle Time bits “D[7:5]” of the
Configuration
conversion rates are supported.
Refer to Section 1.9 of the Datasheet for a
detailed description of the Automatic Conversion
Mode.
4.7 Power Supply Connections
The analog supply voltage (V
+2.7V to +5.5V. The Evaluation system provides a
handful of power supply options via the JP5
header (see Table 1). V
LM4050-4.1 Shunt Reference, the LM1117MPX-
3.3 LDO from the WV4 board, or an external
supply.
precision reference for the ADC121C021.
NOTE: In Computer mode, if V
than 3.3V in Computer mode, an external 3.3V
pull-up supply is needed.
3.3V CMOS logic thresholds of the WaveVision4
board are met for SDA and SCL.
To use an external pull-up supply, remove the
jumper at JP2 and connect the supply to pin 2 of
JP2 or VIA6. An external pull-up supply will also
improve the dynamic performance of the ADC.
Typical supply currents when applying an external
supply to TP7 (VA_EXT) and performing ADC
conversions are as follows:
Note: A majority of this current is for powering
devices external to the ADC121C021 such as the
pull-up resistors and the input amplifier.
When operating in the computer mode, the supply
voltage for V
supplied directly by the WV4 board through J1.
The external supply voltage is selected by placing
a jumper across pins 9 & 10 of JP5, applying a
power source with a 300mA current limit to TP7,
and grounding TP6.
directly from the WV4 board, place a shorting
jumper across pins 3 & 4 of JP5. To use the 3.3V
supply directly from the WV4 board, place a
shorting jumper across pins 1 & 2 of JP5. To use
the LM4050 4.1V Shunt Reference, place a
shorting jumper across pins 7 & 8 of JP5. For the
best performance, use a clean external supply.
8
For V
For V
National
“read”
It is activated by writing a non-zero
A
A
A
= +3.3V, I = 8mA
= +5.0V, I = 11mA
Register.
can be applied externally or
instructions
recommends
To use the 5.0V supply
A
can be driven by the
This will ensure the
Various
A
A
) can range from
is driven with less
from
the
automatic
the
LM4050
I
2
C
When operating in Stand Alone mode, always use
an external supply. Apply a +5.0V power source
with a current limit of 100mA to TP7, ground TP6,
and place a shorting jumper across pins 9 & 10 of
JP5.
Note: The +3.3V required to power the EEPROM
(U4) is obtained through J2 from the WV4 board.
The EEPROM is used to identify the type of Eval
Board connected to the WaveVision system in
Computer Mode.
5.0 Software Operation and Settings
The WaveVision 4 software is included with the
WV4 board and the latest version can be
downloaded for free from National's web site at
http://www.national.com/adc.
software version 4.4 or later is required to
evaluate this device with the WaveVision system.
5.1 Software Quick Start
To install this software, follow the procedure in the
WV4 Board User's Guide. Once the software is
installed, run and set it up as follows:
1. Connect the WV4 board to the host computer
2. From the WaveVision main menu, go to
with a USB cable.
Settings and then Capture Settings to open
the System Settings window (Figure 9) and
select the following:
WaveVision 4 (USB)
Number of Samples: 2k to 128k, as
desired
Data Format: Binary
Figure 9: System Settings window
http://www.national.com
WaveVision4