DEM-OPA26XXE [ETC]
DEM-OPA26xxE - Evaluation Fixture ; DEM - OPA26xxE - 评价灯具\n
| 型号： | DEM-OPA26XXE |
| 厂家： | 
ETC |
| 描述： | DEM-OPA26xxE - Evaluation Fixture
|
| 文件： | 总2页 (文件大小：43K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
®
DEM-OPA26xxE
EVALUATION FIXTURE
MEASUREMENT TIPS
DESCRIPTION
This evaluation board, and the component values shown, are
designed to operate in a 50Ω environment. Most data sheet
plots are obtained this way. It is easy to change the component
values for different input and output impedance levels.
The DEM-OPA26xxE evaluation board is an unpopulated
PCB for dual, wideband op amps in MSOP-8 packages. It
supports Burr-Brown’s OPA2650E, OPA2658E and future
MSOP-8 dual op amps. Figure 1 shows the pinout that this
PCB supports.
Do not use high impedance probes; they represent a heavy
capacitive load to the op amps, and will alter their response.
Instead, use low impedance (≤ 500Ω) probes with adequate
bandwidth; the probe input capacitance and resistance set an
upper limit on the measurement bandwidth. If a high imped-
ance probe must be used, place a 100Ω resistor on the probe
tip to isolate its capacitance from the circuit.
For more information on component selection for a particular
dual op amp, and good PCB layout techniques, see the op
amp’s data sheet.
The ordering number for this board is MKT-349. Limit of 5 per
customer.
CIRCUIT SCHEMATIC
Top View
MSOP-8
The circuit schematic in Figure 2 shows the connections for all
possible components. Not all of the components are used for
each possible configuration.
Output1
1
2
3
4
8
7
6
5
+VS
Table I below shows suggested component values for the
OPA2650E in three different configurations: Non-Inverting
Amplifier (NIA), Inverting Amplifier (IA) and Difference
Amplifier (DA). The gain for the Difference Amp is the
differential mode gain. Other dual op amps can also be easily
set up; see their data sheets to select component values.
–Input1
+Input1
–VS
Output2
–Input2
+Input2
The resistors R1, R4, R9 and R12 are used to set the input
impedance. Resistors R8 and R16 set the output impedance.
The values in Table I support test equipment with 50Ω input
and output impedances; other source and load impedances are
easily accommodated.
FIGURE 1. Pin Configuration.
CONFIGURATION
Gain
NIA
+2
IA
–1
DA
C1 and C2 should be size 1206, multi-layer ceramic chip
capacitors, or equivalent. C3 and C4 should be size 3528 16V
tantalum capacitors. R1 through R16 should be size 1206, metal
film chip resistors, or equivalent. J1 - J6 are SMA or SMB
connectors. P1 and P2 are power connectors, ED555/2DS from
On-Shore Technology.
+1
0.1µF
C1, C2
0.1µF
0.1µF
4.7µF
Not Used
Not Used
20.0Ω
56.2Ω
C3, C4
4.7µF
4.7µF
R1, R9
49.9Ω
53.6Ω
R2, R10
R3, R11
R4, R12
R5, R13
R6, R14
R7, R15
R8, R16
20.0Ω
402Ω
Not Used
Not Used
Not Used
RG = 402Ω
RF = 402Ω
49.9Ω
402Ω
BOARD LAYOUT
61.9Ω
This evaluation board is a two layer PCB. It uses a ground
plane on the bottom, and signal and power traces on the top.
The ground plane has been opened up around op amp pins
sensitive to capacitive loading. Power supply traces are laid
out to keep current loop areas to a minimum. The SMA
connectors may be mounted vertically or horizontally.
RG = 402Ω
Not Used
RF = 402Ω
49.9Ω
RG = 402Ω
Not Used
RF = 402Ω
49.9Ω
NOTES: (1) Values shown are for the OPA2650E dual op amp. See the data sheet
for information on selecting these values. (2) RF and RG refer to the “feedback” and
“gain-setting” resistors for current-feedback op amps.
The location and type of capacitors used for power-supply
bypassing are crucial to high frequency amplifiers. The tanta-
lum capacitors, C3 and C4, do not need to be as close to pins
8 and 4 on your PCB, and may be shared with other amplifiers.
TABLE I. Example Component Selection Guide with
50Ω I/O Impedance.
See the data sheet for more information on proper board layout
techniques, and component selection.
International Airport Industrial Park
•
Mailing Address: PO Box 11400, Tucson, AZ 85734
•
Street Address: 6730 S. Tucson Blvd., Tucson, AZ 85706
• Tel: (520) 746-1111
Twx: 910-952-1111 Internet: http://www.burr-brown.com/
•
•
Cable: BBRCORP Telex: 066-6491
•
•
FAX: (520) 889-1510 Immediate Product Info: (800) 548-6132
•
© 1997 Burr-Brown Corporation
LI-493A
Printed in U.S.A. October, 1999
R2
J1
3
2
R8
J3
+INA
–INA
1/2
1
OUTA
OPA26xxE
R1
R3
4
R7
R5
J2
C2
R4
R6
P1
P2
+VS
–VS
GND
+
C3
GND
C4
+
C1
R10
J4
8
5
6
R16
J6
+INB
1/2
OPA26xxE
7
OUTB
R9
R11
4
R15
R13
J5
–INB
R12
R14
FIGURE 2. Circuit Schematic for DEM-OPA26xxE.
FIGURE 4. Bottom Layout with Silk-Screen (bottom view).
FIGURE 3. Top Layout with Silk-Screen (top view).
The information provided herein is believed to be reliable; however, BURR-BROWN assumes no responsibility for inaccuracies or omissions. BURR-BROWN assumes
no responsibility for the use of this information, and all use of such information shall be entirely at the user’s own risk. Prices and specifications are subject to change
without notice. No patent rights or licenses to any of the circuits described herein are implied or granted to any third party. BURR-BROWN does not authorize or warrant
any BURR-BROWN product for use in life support devices and/or systems.
®
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DEM-OPA26xxE
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