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参数资料
| 型号： | AD7243 |
| 厂商： | Analog Devices, Inc. |
| 英文描述： | LC2MOS 12-Bit Serial DACPORT |
| 中文描述： | LC2MOS 12位串行DACPORT |
| 文件页数： | 7/12页 |
| 文件大小： | 171K |
| 代理商： | AD7243 |
REV. A
–7–
AD7243
Although 16 bits of data are clocked into the input register, only
the latter 12 bits get transferred into the DAC latch. The first 4
bits in the 16 bit stream are don’t cares since their value does
not affect the DAC latch data. Therefore, the data format is 4
don’t cares followed by the 12-bit data word with the LSB as
the last bit in the serial stream.
There are two ways in which the DAC latch and hence the ana-
log output may be updated. The status of the
LDAC
input is
examined after
SYNC
is taken low. Depending on its status, one
of two update modes is selected.
If
LDAC
= 0, then the automatic update mode is selected. In
this mode the DAC latch and analog output are updated auto-
matically when the last bit in the serial data stream is clocked in.
The update thus takes place on the sixteenth falling SCLK edge.
If
LDAC
= 1, then the automatic update is disabled and the
DAC latch is updated by taking
LDAC
low any time after the
16-bit data transfer is complete. The update now occurs on the
falling edge of
LDAC
. Note that the
LDAC
input must be taken
back high again before the next data transfer is initiated.
Serial Data Loading Format (Daisy-Chain Mode)
By connecting DCEN high the daisy-chain mode is enabled.
This mode of operation is designed for multi-DAC systems
where several AD7243s may be connected in cascade (see Fig-
ure 16). In this mode the internal gating circuitry on SCLK is
disabled, and a serial data output facility is enabled. The inter-
nal gating signal is permanently active (low) so that the SCLK
signal is continuously applied to the input shift register when
SYNC
is low. The data is clocked into the register on each fall-
ing SCLK edge after
SYNC
going low. If more than 16 clock
pulses are applied, the data ripples out of the shift register and
appears on the SDO line. By connecting this line to the SDIN
input on the next AD7243 in the chain, a multi-DAC interface
may be constructed. Sixteen SCLK pulses are required for each
DAC in the system. Therefore, the total number of clock cycles
must equal 16N where N is the total number of devices in the
chain. When the serial transfer to all devices is complete,
SYNC
should be taken high. This prevents any further data being
clocked into the input register.
A continuous SCLK source may be used if it can be arranged
that
SYNC
is held low for the correct number of clock cycles.
Alternatively, a burst clock containing the exact number of clock
cycles may be used and
SYNC
taken high some time later.
When the transfer to all input registers is complete, a common
LDAC
signal updates all DAC latches with the lower 12 bits of
data in each input register. All analog outputs are therefore up-
dated simultaneously on the falling edge of
LDAC
.
Clear Function (
CLR
)
The clear function bypasses the input shift register and loads the
DAC Latch with all 0s. It is activated by taking
CLR
low. In all
ranges except the Offset Binary bipolar range (–5 V to +5 V) the
output voltage is reset to 0 V. In the offset binary bipolar range
the output is set to –REFIN. The clear function is especially
useful at power-up as it enables the output to be reset to a
known state.
SCLK
DB11 (N)
MSB
DB0 (N)
LSB
*
= DON'T CARE
SDIN
SYNC
LDAC
CLR
DB0 (N)
LSB
SDO
DB15 (N)*
DB15*
(N + 1)
DB11 (N + 1)
MSB
DB0 (N + 1)
LSB
UNDEFINED
DB15 (N)*
DB11 (N)
MSB
t
1
t
2
t
3
t
5
t
4
t
11
t
6
t
7
t
8
t
9
t
10
Figure 8. Timing Diagram (Daisy-Chain Mode)
相关PDF资料 |
PDF描述 |
|---|---|
| AD7243AN | LC2MOS 12-Bit Serial DACPORT |
| AD7243AQ | LC2MOS 12-Bit Serial DACPORT |
| AD7243AR | LC2MOS 12-Bit Serial DACPORT |
| AD7243BN | 47 UF, 20V CAP., TANTALUM |
| AD7243BQ | LC2MOS 12-Bit Serial DACPORT |
相关代理商/技术参数 |
参数描述 |
|---|---|
| AD7243AN | 功能描述:IC SRL DAC 12BIT LC2MOS 16-DIP RoHS:否 类别:集成电路 (IC) >> 数据采集 - 数模转换器 系列:DACPORT® 产品培训模块:Data Converter Fundamentals DAC Architectures 标准包装:750 系列:- 设置时间:7µs 位数:16 数据接口:并联 转换器数目:1 电压电源:双 ± 功率耗散（最大）:100mW 工作温度:0°C ~ 70°C 安装类型:表面贴装 封装/外壳:28-LCC（J 形引线） 供应商设备封装:28-PLCC（11.51x11.51） 包装:带卷 (TR) 输出数目和类型:1 电压，单极；1 电压，双极 采样率（每秒）:143k |
| AD7243ANZ | 功能描述:IC SRL DAC 12BIT LC2MOS 16-DIP RoHS:是 类别:集成电路 (IC) >> 数据采集 - 数模转换器 系列:DACPORT® 产品培训模块:Data Converter Fundamentals DAC Architectures 标准包装:750 系列:- 设置时间:7µs 位数:16 数据接口:并联 转换器数目:1 电压电源:双 ± 功率耗散（最大）:100mW 工作温度:0°C ~ 70°C 安装类型:表面贴装 封装/外壳:28-LCC（J 形引线） 供应商设备封装:28-PLCC（11.51x11.51） 包装:带卷 (TR) 输出数目和类型:1 电压，单极；1 电压，双极 采样率（每秒）:143k |
| AD7243AQ | 制造商:Rochester Electronics LLC 功能描述:- Bulk |
| AD7243AR | 功能描述:IC SRL DAC 12BIT LC2MOS 16-SOIC RoHS:否 类别:集成电路 (IC) >> 数据采集 - 数模转换器 系列:DACPORT® 产品培训模块:Data Converter Fundamentals DAC Architectures 标准包装:750 系列:- 设置时间:7µs 位数:16 数据接口:并联 转换器数目:1 电压电源:双 ± 功率耗散（最大）:100mW 工作温度:0°C ~ 70°C 安装类型:表面贴装 封装/外壳:28-LCC（J 形引线） 供应商设备封装:28-PLCC（11.51x11.51） 包装:带卷 (TR) 输出数目和类型:1 电压，单极；1 电压，双极 采样率（每秒）:143k |
| AD7243AR-REEL | 功能描述:IC DAC 12BIT W/AMP W/REF 16-SOIC RoHS:否 类别:集成电路 (IC) >> 数据采集 - 数模转换器 系列:DACPORT® 标准包装:47 系列:- 设置时间:2µs 位数:14 数据接口:并联 转换器数目:1 电压电源:单电源 功率耗散（最大）:55µW 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:28-SSOP（0.209"，5.30mm 宽） 供应商设备封装:28-SSOP 包装:管件 输出数目和类型:1 电流，单极；1 电流，双极 采样率（每秒）:* |
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