Home >> ADC0804 Search >> National Semiconductor ADC0804 Datasheet

ADC0804 Datasheet

8-Bit uP Compatible A/D Converters

No Preview Available !

ADC0804 pdf
Functional Description (Continued)
Transfer Function
Error Plot
DS005671-85
DS005671-86
FIGURE 3. Clarifying the Error Specs of an A/D Converter
Accuracy=±12 LSB
2.0 FUNCTIONAL DESCRIPTION
The ADC0801 series contains a circuit equivalent of the
256R network. Analog switches are sequenced by succes-
sive approximation logic to match the analog difference input
voltage [VIN(+) − VIN(−)] to a corresponding tap on the R net-
work. The most significant bit is tested first and after 8 com-
parisons (64 clock cycles) a digital 8-bit binary code (1111
1111 = full-scale) is transferred to an output latch and then
an interrupt is asserted (INTR makes a high-to-low transi-
tion). A conversion in process can be interrupted by issuing a
second start command. The device may be operated in the
free-running mode by connecting INTR to the WR input with
CS =0. To ensure start-up under all possible conditions, an
external WR pulse is required during the first power-up
cycle.
On the high-to-low transition of the WR input the internal
SAR latches and the shift register stages are reset. As long
as the CS input and WR input remain low, the A/D will remain
in a reset state. Conversion will start from 1 to 8 clock peri-
ods after at least one of these inputs makes a low-to-high
transition.
A functional diagram of the A/D converter is shown in Figure
4. All of the package pinouts are shown and the major logic
control paths are drawn in heavier weight lines.
The converter is started by having CS and WR simulta-
neously low. This sets the start flip-flop (F/F) and the result-
ing “1” level resets the 8-bit shift register, resets the Interrupt
(INTR) F/F and inputs a “1” to the D flop, F/F1, which is at the
input end of the 8-bit shift register. Internal clock signals then
transfer this “1” to the Q output of F/F1. The AND gate, G1,
combines this “1” output with a clock signal to provide a reset
signal to the start F/F. If the set signal is no longer present
(either WR or CS is a “1”) the start F/F is reset and the 8-bit
shift register then can have the “1” clocked in, which starts
the conversion process. If the set signal were to still be
present, this reset pulse would have no effect (both outputs
of the start F/F would momentarily be at a “1” level) and the
8-bit shift register would continue to be held in the reset
mode. This logic therefore allows for wide CS and WR sig-
nals and the converter will start after at least one of these
signals returns high and the internal clocks again provide a
reset signal for the start F/F.
www.national.com
18
National Semiconductor
National Semiconductor


PDF Click to Download PDF File

PDF View for Mobile




Related Start with ADC080*

[ ADC0800 National Semiconductor ]     [ ADC0800 Texas Instruments ]     [ ADC08004-1CD NXP ]     [ ADC08004-1CN NXP ]     [ ADC08004-1LCD NXP ]     [ ADC08004-1LCN NXP ]     [ ADC0800PCD National Semiconductor ]     [ ADC0800PD National Semiconductor ]     [ ADC0801 National Semiconductor ]     [ ADC0801 Texas Instruments ]     [ ADC0801S040 NXP Semiconductors ]     [ ADC0802 Intersil Corporation ]     [ ADC0802 National Semiconductor ]     [ ADC0802 Harris ]     [ ADC0802 Texas Instruments ]     [ ADC0803 NXP ]     [ ADC0803 Intersil Corporation ]     [ ADC0803 National Semiconductor ]     [ ADC0803 Harris ]     [ ADC0803 Texas Instruments ]     [ ADC0800 National Semiconductor ]     [ ADC0800 Texas Instruments ]     [ ADC08004-1CD NXP ]     [ ADC08004-1CN NXP ]     [ ADC08004-1LCD NXP ]     [ ADC08004-1LCN NXP ]     [ ADC0800PCD National Semiconductor ]     [ ADC0800PD National Semiconductor ]     [ ADC0801 National Semiconductor ]     [ ADC0801 Texas Instruments ]    


Searches related to ADC0804 part

Find Chips CBC RS online RUTRONIK 24
Component Distributors NexGen Digital Richardson RFPD ICC
Beyond Components NAC PEI-Genesis Powell Electronics
TME Ameya 360 Power & Signal Datasheets360
Freelance Electronics Sager Electronics Terminals & Connectors TTI

0  1  2  3  4  5  6  7  8  9  A  B  C  D  E  F  G  H  I  J  K  L  M  N  O  P  Q  R  S  T  U  V  W  X  Y  Z
@ 2014 :: DatasheetsPDF.com :: Semiconductors Datasheet Search & Download Site