- 您現(xiàn)在的位置：買賣IC網 > PDF目錄375239 > AD7823 (Analog Devices, Inc.) 8-Bit ADC in 8-Lead microSOIC/DIP(8位A/D轉換器) PDF資料下載
參數(shù)資料
| 型號： | AD7823 |
| 廠商： | Analog Devices, Inc. |
| 英文描述： | 8-Bit ADC in 8-Lead microSOIC/DIP(8位A/D轉換器) |
| 中文描述： | 8位ADC的8引腳microSOIC /文憑（8位的A / D轉換器） |
| 文件頁數(shù)： | 9/11頁 |
| 文件大?。?/td> | 158K |
| 代理商： | AD7823 |
AD7823
–9–
REV. A
t
POWER-UP
1
m
s
A
B
t
1
CONVST
D
OUT
SCLK
CURRENT CONVERSION
RESULT
Figure 15. Mode 2 Operation Timing
CONVST
D
OUT
SCLK
t
3
t
4
t
7
t
6
t
8
1
2
3
4
5
6
7
8
DB7
DB6
DB5
DB4
DB3
DB2
DB1
DB0
t
5
Figure 16. Serial Interface Timing
Mode 2 Operation (Automatic Power-Down)
When used in this mode of operation, the part automatically
powers down at the end of a conversion. This is achieved by
leaving the
CONVST
signal low until the end of the conversion.
The timing diagram in Figure 15 shows how to operate the part
in this mode. If the AD7823 is powered down, the rising edge of
the
CONVST
pulse causes the part to power up. When the part
has powered up (
≈
1
μ
s after the rising edge of
CONVST
), the
CONVST
signal is brought low, and a conversion is initiated
on this falling edge of the
CONVST
signal. The conversion
takes 4.5
μ
s and after this time, the conversion result is latched
into the serial shift register and the part powers down. There-
fore, when the part is operated in Mode 2, the effective conver-
sion time is equal to the power-up time (1
μ
s) and the SAR
conversion time (4.5
μ
s), i.e., 5.5
μ
s.
As in the case of Mode 1 operation, the rising edge of the
CONVST
pulse enables the serial port of the AD7823—see
Serial Interface section. If a serial read is initiated soon after this
rising edge (Point “A”), i.e., before the end of the conversion,
then the result of the previous conversion is shifted out on pin
D
OUT
. In order to read the result of the current conversion, the
user must wait at least 4.5
μ
s after the falling edge of
CONVST
before initiating a serial read. The serial port of the AD7823 is
still functional even though the AD7823 has been powered
down. Note: A serial read should not cross the reset rising edge
of
CONVST
.
Because it is possible to do a serial read from the part while it is
powered down, the AD7823 is powered up only to do the con-
version and is immediately powered down at the end of a con-
version. This significantly improves the power consumption of
the part at slower throughput rates—see Power vs. Throughput
Rate section.
Note: Although the AD7823 takes 1
μ
s to power up after the
rising edge of
CONVST
, it is not necessary to leave
CONVST
high for 1
μ
s after the rising edge before bringing it low to
initiate a conversion. If the
CONVST
signal goes low before 1
μ
s
in time has elapsed, the power-up time is timed out internally
and a conversion is initiated. Hence the AD7823 is guaranteed
to have always powered up before a conversion is initiated—even if
the
CONVST
pulsewidth is <1
μ
s. If the
CONVST
width is
>1
μ
s a conversion is initiated on the falling edge.
SERIAL INTERFACE
The serial interface of the AD7823 consists of three wires, a
serial clock input SCLK, serial port enable
CONVST
and a
serial data output D
OUT
, see Figure 16 below. The serial inter-
face is designed to allow easy interfacing to most microcontrollers,
e.g., PIC16C, PIC17C, QSPI and SPI, without the need for any
gluing logic. When interfacing to the 8051, the SCLK must be
inverted. The “Microprocessor Interface” section explains how
to interface to some popular microcontrollers.
Figure 16 shows the timing diagram for a serial read from the
AD7823. The serial interface works with both a continuous and
a noncontinuous serial clock. The rising edge of the
CONVST
signal RESETS a counter, which counts the number of serial
clocks to ensure the correct number of bits are shifted out of the
serial shift registers. The SCLK is ignored once the correct
number of bits have been shifted out. In order for another serial
transfer to take place, the counter must be reset by the falling
edge of the eighth SCLK. Data is clocked out from the D
OUT
line on the first rising SCLK edge after the rising edge of the
CONVST
signal and on subsequent SCLK rising edges. The
D
OUT
pin goes back into a high impedance state on the falling
edge of the eighth SCLK. In multipackage applications, the
CONVST
signal can be used as a chip select signal. The serial
interface will not shift data out until it receives a rising edge on
the
CONVST
pin.
相關PDF資料 |
PDF描述 |
|---|---|
| AD7824 | High Speed 4-Channel 8-Bit ADC(四通道LC2MOS高速8位A/D轉換器) |
| AD7834AN | 2.35V-5.25V, 12 bit, 1MSPS, Serial ADC 6-SOT-23 -40 to 125 |
| AD7834AR | 2.35V-5.25V, 12 bit, 1MSPS, Serial ADC 6-SOT-23 -40 to 125 |
| AD7834BN | 2.35V-5.25V, 12 bit, 1MSPS, Serial ADC 6-SC70 -40 to 125 |
| AD7834BR | 2.35V-5.25V, 12 bit, 1MSPS, Serial ADC 6-SC70 -40 to 125 |
相關代理商/技術參數(shù) |
參數(shù)描述 |
|---|---|
| AD7823YN | 制造商:Analog Devices 功能描述:ADC Single SAR 200ksps 8-bit Serial 8-Pin PDIP 制造商:Rochester Electronics LLC 功能描述:8-BIT SERIAL SINGLE ADC I.C. - Bulk 制造商:Analog Devices 功能描述:IC 8BIT ADC 7823 DIP8 |
| AD7823YNZ | 制造商:Analog Devices 功能描述:ADC Single SAR 200ksps 8-bit Serial 8-Pin PDIP 制造商:Analog Devices 功能描述:IC 8BIT ADC 7823 DIP8 |
| AD7823YNZ | 制造商:Analog Devices 功能描述:IC 8BIT ADC 7823 DIP8 |
| AD7823YR | 制造商:Analog Devices 功能描述:ADC Single SAR 200ksps 8-bit Serial 8-Pin SOIC N 制造商:Rochester Electronics LLC 功能描述:8-BIT SERIAL SINGLE ADC I.C. - Bulk 制造商:Analog Devices 功能描述:IC 8-BIT ADC |
| AD7823YRM | 制造商:Analog Devices 功能描述:ADC Single SAR 200ksps 8-bit Serial 8-Pin MSOP 制造商:Rochester Electronics LLC 功能描述:8-BIT SERIAL SINGLE ADC I.C. - Bulk 制造商:Analog Devices 功能描述:IC 8-BIT ADC |
發(fā)布緊急采購，3分鐘左右您將得到回復。