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參數(shù)資料
| 型號： | DAC908U |
| 英文描述： | 8-Bit, 165MSPS DIGITAL-TO-ANALOG CONVERTER |
| 中文描述： | 8位，165MSPS的速率，數(shù)字模擬轉(zhuǎn)換器 |
| 文件頁數(shù)： | 10/15頁 |
| 文件大?。?/td> | 180K |
| 代理商： | DAC908U |
DAC908
10
APPLICATION INFORMATION
THEORY OF OPERATION
The architecture of the DAC908 uses the current steering
technique to enable fast switching and a high update rate.
The core element within the monolithic D/A converter is an
array of segmented current sources, which are designed to
deliver a full-scale output current of up to 20mA (see
Figure 1). An internal decoder addresses the differential
current switches each time the DAC is updated and a
corresponding output current is formed by steering all
currents to either output summing node, I
OUT
or I
OUT
.
The complementary outputs deliver a differential output
signal, which improves the dynamic performance through
reduction of even-order harmonics, common-mode signals
(noise), and double the peak-to-peak output signal swing by
a factor of two, compared to single-ended operation.
The segmented architecture results in a significant reduc-
tion of the glitch energy, and improves the dynamic perfor-
mance (SFDR) and DNL. The current outputs maintain a
very high output impedance of greater than 200k
.
The full-scale output current is determined by the ratio of
the internal reference voltage (1.24V) and an external
resistor, R
SET
. The resulting I
REF
is internally multiplied by
a factor of 32 to produce an effective DAC output current
that can range from 2mA to 20mA, depending on the value
of R
SET
.
The DAC908 is split into a digital and an analog portion,
each of which is powered through its own supply pin. The
digital section includes edge-triggered input latches and the
decoder logic, while the analog section comprises the cur-
rent source array with its associated switches and the
reference circuitry.
DAC TRANSFER FUNCTION
The total output current, I
OUTFS
, of the DAC908 is the
summation of the two complementary output currents:
I
OUTFS
= I
OUT
+ I
OUT
(1)
The individual output currents depend on the DAC code and
can be expressed as:
I
OUT
= I
OUTFS
(Code/256)
(2)
I
OUT
= I
OUTFS
(255 - Code/256)
(3)
where ‘Code’ is the decimal representation of the DAC data
input word. Additionally, I
OUTFS
is a function of the refer-
ence current I
REF
, which is determined by the reference
voltage and the external setting resistor, R
SET
.
I
OUTFS
= 32 I
REF
= 32 V
REF
/R
SET
(4)
In most cases the complementary outputs will drive resistive
loads or a terminated transformer. A signal voltage will
develop at each output according to:
V
OUT
= I
OUT
R
LOAD
(5)
V
OUT
= I
OUT
R
LOAD
(6)
FIGURE 1. Functional Block Diagram of the DAC908.
PMOS
Current
Source
Array
LSB
Switches
Segmented
MSB
Switches
+1.24V Ref
Latches and Switch
Decoder Logic
8-Bit Data Input
D7...D0
DAC908
Full-Scale
Adjust
Resistor
Ref
Control
Amp
Ref
Buffer
BW
+V
D
+V
A
R
SET
2k
CLK
DGND
Ref
Input
0.1
μ
F
INT/EXT
I
OUT
I
OUT
BYP
PD
20pF
50
50
20pF
1:1
V
OUT
0.1
μ
F
400pF
0.1
μ
F
+3V to +5V
Analog
Bandwidth
Control
+3V to +5V
Digital
FSA
REF
IN
AGND
Analog
Ground
Digital
Ground
Power Down
(internal pull-down)
Clock
Input
NOTE: Supply bypassing not shown.
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| DAC9331-14-1 | 14-Bit Digital-to-Analog Converter |
| DAC9331-14-2 | 14-Bit Digital-to-Analog Converter |
| DAC9331-16-4 | 16-Bit Digital-to-Analog Converter |
| DAC9331-16-5 | 16-Bit Digital-to-Analog Converter |
| DAC9331-16-6 | 16-Bit Digital-to-Analog Converter |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| DAC908U | 制造商:Texas Instruments 功能描述:8 BIT DIGITAL/ANALOG CONVERTER 8 RESOLU |
| DAC908U/1K | 功能描述:數(shù)模轉(zhuǎn)換器- DAC 8-Bit 165MSPS SpeedPlus DAC RoHS:否 制造商:Texas Instruments 轉(zhuǎn)換器數(shù)量:1 DAC 輸出端數(shù)量:1 轉(zhuǎn)換速率:2 MSPs 分辨率:16 bit 接口類型:QSPI, SPI, Serial (3-Wire, Microwire) 穩(wěn)定時間:1 us 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:SOIC-14 封裝:Tube |
| DAC908U/1KG4 | 功能描述:數(shù)模轉(zhuǎn)換器- DAC 8-Bit 165MSPS SpeedPlus DAC RoHS:否 制造商:Texas Instruments 轉(zhuǎn)換器數(shù)量:1 DAC 輸出端數(shù)量:1 轉(zhuǎn)換速率:2 MSPs 分辨率:16 bit 接口類型:QSPI, SPI, Serial (3-Wire, Microwire) 穩(wěn)定時間:1 us 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:SOIC-14 封裝:Tube |
| DAC908UG4 | 功能描述:數(shù)模轉(zhuǎn)換器- DAC 8-Bit 165MSPS SpeedPlus DAC RoHS:否 制造商:Texas Instruments 轉(zhuǎn)換器數(shù)量:1 DAC 輸出端數(shù)量:1 轉(zhuǎn)換速率:2 MSPs 分辨率:16 bit 接口類型:QSPI, SPI, Serial (3-Wire, Microwire) 穩(wěn)定時間:1 us 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:SOIC-14 封裝:Tube |
| DAC9331-14 | 制造商:APITECH 制造商全稱:APITECH 功能描述:14-Bit Multiplying DAC |
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