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參數(shù)資料
| 型號(hào)： | OPA688U |
| 元件分類(lèi)： | 限幅放大器 |
| 英文描述： | Unity Gain Stable, Wideband VOLTAGE LIMITING AMPLIFIER |
| 中文描述： | 單位增益穩(wěn)定，寬帶電壓限幅放大器 |
| 文件頁(yè)數(shù)： | 13/16頁(yè) |
| 文件大?。?/td> | 185K |
| 代理商： | OPA688U |
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OPA688
DESIGN-IN TOOLS
APPLICATIONS SUPPORT
The Burr-Brown Applications Department is available for
design assistance at 1-800-548-6132 (US/Canada only). The
Burr-Brown Internet web page (http://www.burr-brown.com)
has the latest data sheets and other design aids.
DEMONSTRATION BOARDS
Two PC boards are available to assist in the initial evaluation
of circuit performance of the OPA688 in both package
styles. These are available as an unpopulated PCB with
descriptive documentation. See the demonstration board
literature for more information. The summary information
for these boards is shown below:
The limiters have a very sharp transition from the linear
region of operation to output limiting. This allows the limiter
voltages to be set very near (<100mV) the desired signal
range. The distortion performance is also very good near the
limiter voltages.
CIRCUIT LAYOUT
Achieving optimum performance with the high frequency
OPA688 requires careful attention to layout design and
component selection. Recommended PCB layout techniques
and component selection criteria are:
a)
Minimize parasitic capacitance to any ac ground
for all
of the signal I/O pins. Open a window in the ground and
power planes around the signal I/O pins, and leave the
ground and power planes unbroken elsewhere.
b)
Provide a high quality power supply.
Use linear regu-
lators, ground plane and power planes to provide power.
Place high frequency 0.1
μ
F decoupling capacitors < 0.2"
away from each power supply pin. Use wide, short traces to
connect to these capacitors to the ground and power planes.
Also use larger (2.2
μ
F to 6.8
μ
F) high frequency decoupling
capacitors to bypass lower frequencies. They may be some-
what further from the device, and be shared among several
adjacent devices.
c)
Place external components close
to the OPA688. This
minimizes inductance, ground loops, transmission line ef-
fects and propagation delay problems. Be extra careful with
the feedback (R
F
), input and output resistors.
d)
Use high frequency components
to minimize parasitic
elements. Resistors should be a very low reactance type.
Surface mount resistors work best and allow a tighter layout.
Metal film or carbon composition axially-leaded resistors
can also provide good performance when their leads are as
short as possible. Never use wirewound resistors for high
frequency applications. Remember that most potentiometers
have large parasitic capacitances and inductances.
Multilayer ceramic chip capacitors work best and take up
little space. Monolithic ceramic capacitors also work very
well. Use RF type capacitors with low ESR and ESL. The
large power pin bypass capacitors (2.2
μ
F to 6.8
μ
F) should
be tantalum for better high frequency and pulse perfor-
mance.
e)
Choose low resistor values
to minimize the time constant
set by the resistor and its parasitic parallel capacitance. Good
metal film or surface mount resistors have approximately
0.2pF parasitic parallel capacitance. For resistors > 1.5k
,
this adds a pole and/or zero below 500MHz.
Make sure that the output loading is not too heavy. The
recommended 402
feedback resistor is a good starting
point in your design.
LITERATURE
REQUEST
NUMBER
DEMONSTRATION
BOARD
PACKAGE
PRODUCT
DEM-OPA68xP
DEM-OPA68xU
8-Pin DIP
SO-8
OPA68xP
OPA68xU
MKT-350
MKT-351
Contact the Burr-Brown Application Department for avail-
ability of these boards.
SPICE MODELS
Computer simulation of circuit performance using SPICE is
often useful when analyzing the performance of analog
circuits and systems. This is particularly true for high speed
active devices, like the OPA688, where parasitic capacitance
and inductance can have a major effect on frequency re-
sponse.
SPICE models are available through the Burr-Brown web
site (www.burr-brown.com). These models do a good job of
predicting small-signal AC and transient performance under
a wide variety of operating conditions. They do not do as
well in predicting the harmonic distortion, temperature ef-
fects or differential gain and phase characteristics. These
models do not distinguish between the AC performance of
different package types.
OPERATING INFORMATION
THEORY OF OPERATION
The OPA688 is a voltage feedback op amp that is unity-gain
stable. The output voltage is limited to a range set by the
voltage on the limiter pins (5 and 8). When the input tries to
overdrive the output, the limiters take control of the output
buffer. This avoids saturating any part of the signal path,
giving quick overdrive recovery and excellent limiter accu-
racy at any signal gain.
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| OPA688P | ECONOLINE: RB & RA - Dual Output from a Single Input Rail- Power Sharing on Output- Industry Standard Pinout- 1kVDC & 2kVDC Isolation- Custom Solutions Available- UL94V-0 Package Material- Efficiency to 85% |
| OPA688 | Unity Gain Stable, Wideband VOLTAGE LIMITING AMPLIFIER |
| OPA689U | Wideband, High Gain VOLTAGE LIMITING AMPLIFIER |
| OPA689P | Wideband, High Gain VOLTAGE LIMITING AMPLIFIER |
| OPA689 | Wideband, High Gain VOLTAGE LIMITING AMPLIFIER |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| OPA688U/2K5 | 制造商:未知廠(chǎng)家 制造商全稱(chēng):未知廠(chǎng)家 功能描述:Voltage-Feedback Operational Amplifier |
| OPA689 | 制造商:BB 制造商全稱(chēng):BB 功能描述:Wideband, High Gain VOLTAGE LIMITING AMPLIFIER |
| OPA689M | 制造商:TI 制造商全稱(chēng):Texas Instruments 功能描述:GAIN 4 STABLE WIDEBAND VOLTAGE-LIMITING AMPLIFIER |
| OPA689MJD | 制造商:Texas Instruments 功能描述:OP Amp Single Volt Fdbk ±6V/12V 8-Pin SBCDIP Tube |
| OPA689P | 制造商:Rochester Electronics LLC 功能描述:- Bulk 制造商:Texas Instruments 功能描述: |
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