參數(shù)資料
型號: AD9764-EB
廠商: Analog Devices, Inc.
英文描述: 14-Bit, 125 MSPS TxDAC D/A Converter
中文描述: 14位,125 MSPS的TxDAC系列D / A轉(zhuǎn)換
文件頁數(shù): 11/22頁
文件大小: 307K
代理商: AD9764-EB
REV. B
AD9764
–11–
The second method may be used in a dual-supply system in
which the common-mode voltage of REFIO is fixed, and I
REF
is
varied by an external voltage, V
GC
, applied to R
SET
via an ampli-
fier. An example of this method is shown in Figure 26 in which
the internal reference is used to set the common-mode voltage
of the control amplifier to 1.20 V. The external voltage, V
GC
, is
referenced to ACOM and should not exceed 1.2 V. The value of
R
SET
is such that I
REFMAX
and I
REFMIN
do not exceed 62.5
μ
A
and 625
μ
A, respectively. The associated equations in Figure 26
can be used to determine the value of R
SET
.
50pF
COMP1 AVDD
REFLO
CURRENT
SOURCE
ARRAY
AVDD
REFIO
FS ADJ
R
SET
AD9764
I
REF
OPTIONAL
BANDLIMITING
CAPACITOR
V
GC
1
m
F
I
REF
= (1.2–V
GC
)/R
SET
WITH V
GC
< V
REFIO
AND 62.5
m
A
#
I
REF
#
625A
+1.2V REF
Figure 26. Dual-Supply Gain Control Circuit
In some applications, the user may elect to use an external
control amplifier to enhance the multiplying bandwidth,
distortion performance and/or settling time. External amplifiers
capable of driving a 50 pF load such as the AD817 are suitable
for this purpose. It is configured in such a way that it is in
parallel with the weaker internal reference amplifier as shown in
Figure 27. In this case, the external amplifier simply overdrives
the weaker reference control amplifier. Also, since the internal
control amplifier has a limited current output, it will sustain no
damage if overdriven.
50pF
COMP1
+1.2V REF
AVDD
REFLO
CURRENT
SOURCE
ARRAY
AVDD
REFIO
FS ADJ
R
SET
AD9764
V
REF
INPUT
EXTERNAL
CONTROL AMPLIFIER
Figure 27. Configuring an External Reference Control
Amplifier
ANALOG OUTPUTS
The AD9764 produces two complementary current outputs,
I
OUTA
and I
OUTB
, which may be configured for single-end
or differential operation. I
OUTA
and I
OUTB
can be converted into
complementary single-ended voltage outputs, V
OUTA
and
V
OUTB
, via a load resistor, R
LOAD
, as described in the DAC
Transfer Function section by Equations 5 through 8. The
differential voltage, V
DIFF
, existing between V
OUTA
and V
OUTB
can also be converted to a single-ended voltage via a transformer
or differential amplifier configuration.
Figure 28 shows the equivalent analog output circuit of the
AD9764 consisting of a parallel combination of PMOS differen-
tial current switches associated with each segmented current
source. The output impedance of I
OUTA
and I
OUTB
is determined
by the equivalent parallel combination of the PMOS switches
and is typically 100 k
in parallel with 5 pF. Due to the na-
ture of a PMOS device, the output impedance is also slightly
dependent on the output voltage (i.e., V
OUTA
and V
OUTB
) and, to
a lesser extent, the analog supply voltage, AVDD, and full-scale
current, I
OUTFS
. Although the output impedance’s signal depen-
dency can be a source of dc nonlinearity and ac linearity (i.e.,
distortion), its effects can be limited if certain precautions are
noted.
AD9764
AVDD
I
OUTA
I
OUTB
R
LOAD
R
LOAD
Figure 28. Equivalent Analog Output Circuit
I
OUTA
and I
OUTB
also have a negative and positive voltage compli-
ance range. The negative output compliance range of –1.0 V is
set by the breakdown limits of the CMOS process. Operation
beyond this maximum limit may result in a breakdown of the
output stage and affect the reliability of the AD9764. The posi-
tive output compliance range is slightly dependent on the full-
scale output current, I
OUTFS
. It degrades slightly from its nominal
1.2V
50pF
COMP1
+1.2V REF
AVDD
REFLO
CURRENT
SOURCE
ARRAY
AVDD
REFIO
FS ADJ
R
SET
AD9764
I
REF
=
V
REF
/R
SET
AVDD
OPTIONAL
BANDLIMITING
CAPACITOR
V
REF
V
DD
R
FB
OUT1
OUT2
AGND
DB7–DB0
AD7524
AD1580
0.1V TO 1.2V
Figure 25. Single-Supply Gain Control Circuit
相關(guān)PDF資料
PDF描述
AD9764AR 14-Bit, 125 MSPS TxDAC D/A Converter
AD9764ARU 14-Bit, 125 MSPS TxDAC D/A Converter
AD9764* 14-Bit. 125 MSPS TxDAC D/A Converter
AD97651 12-Bit, 125 MSPS Dual TxDAC+ D/A Converter
AD9767 14-Bit, 125 MSPS Dual TxDAC+ D/A Converter
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
AD9764-EBZ 功能描述:BOARD EVAL FOR AD9764 RoHS:是 類別:編程器,開發(fā)系統(tǒng) >> 評估板 - 數(shù)模轉(zhuǎn)換器 (DAC) 系列:TxDAC® 產(chǎn)品培訓(xùn)模塊:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 標(biāo)準(zhǔn)包裝:1 系列:- DAC 的數(shù)量:4 位數(shù):12 采樣率(每秒):- 數(shù)據(jù)接口:串行,SPI? 設(shè)置時間:3µs DAC 型:電流/電壓 工作溫度:-40°C ~ 85°C 已供物品:板 已用 IC / 零件:MAX5581
AD9765 制造商:AD 制造商全稱:Analog Devices 功能描述:Analog Devices: Data Converters: DAC 12-Bit, 10 ns to 100 ns Converters Selection Table
AD97651 制造商:AD 制造商全稱:Analog Devices 功能描述:12-Bit, 125 MSPS Dual TxDAC+ D/A Converter
AD9765AST 功能描述:數(shù)模轉(zhuǎn)換器- DAC 12-Bit 125 MSPS Dual TxDAC+ 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
AD9765ASTRL 制造商:Analog Devices 功能描述:DAC 2-CH Segment 12-bit 48-Pin LQFP T/R 制造商:Analog Devices 功能描述:DAC DUAL CURRENT STEERING 12-BIT 48LQFP - Tape and Reel 制造商:Rochester Electronics LLC 功能描述:12-BIT, 125 MSPS DUAL TXDAC+ - Tape and Reel 制造商:Analog Devices Inc. 功能描述:Digital to Analog Converters - DAC 12-Bit 125 MSPS Dual TxDAC+ 制造商:Analog Devices Inc. 功能描述:Digital to Analog Converters - DAC 12-Bit 125 MSPS Dual 制造商:Analog Devices 功能描述:CONVERTER - DAC