DEM-OPA268XN [ETC]
DEM-OPA268xN - Evaluation Fixture ; DEM - OPA268xN - 评价灯具\n
| 型号： | DEM-OPA268XN |
| 厂家： | 
ETC |
| 描述： | DEM-OPA268xN - 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 |
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DEM-OPA268xN
EVALUATION FIXTURE
DESCRIPTION
R3A
The DEM-OPA268xN demonstration board is an
unpopulated printed circuit board (PCB) for the high
speed dual op amps with disable available in SO-14
packages. The DEM-OPA268xN supports Burr-
Brown’s OPA2680N, OPA2681N, and OPA2682N.
Figure 1 shows the package pinout for this PCB. For
more information on these op amps, and good PCB
layout techniques, see the individual op amp data sheets.
R2A
2
J1A
J2A
R7A
14
IN A
Out A
R4A
R5A
1
3
R1A
4
C6A
R6A
C4
P1
J3A
L2
L1
–VS
GND
+VS
DIS A
C2
C1
R8A
+
+
C3
The ordering number for this board is MKT-353. Limit
of 5 per customer.
J3B
DIS B
Out B
C5
Top View
SO-14
R8B
R3B
R2B
R4B
R5B
C6B
11
6
7
R7B
J1B
J2B
5
–In A
+In A
DIS A
–VS
1
2
3
4
5
6
7
14 Out A
13 NC
12 NC
11 +VS
10 NC
8
IN B
R6B
R1B
FIGURE 2. Circuit Schematic for DEM-OPA268xN.
PART
C1, C2
DESCRIPTION
DIS B
+In B
–In B
Tantalum Chip Capacitor, SMD EIA size 3528, 20V
Multi-Layer Ceramic Chip Cap., SMD 1206, 50V
SMA or SMB Board Jack (Amphenol 901-144-8)
9
8
NC
C3 - C6B
J1A - J3B
L1, L2
Out B
EMI-Suppression Ferrite Chip, SMD 1206
(Steward LI 1206 B 900 R)
P1
Terminal Block, 3.5mm centers
(On-Shore Technology ED555/3DS)
FIGURE 1. Pin Configuration.
R1A - R8B
Metal Film Chip Resistor, SMD 1206, 1/8W
CIRCUIT
TABLE I. Part Descriptions.
The circuit schematic in Figure 2 shows the connec-
tions for all possible components. Each model will
only use some of the components.
For single supply operation, do not connect L2; other-
wise, the –VS input to P1 would be at ground potential.
Disable Pins—Pins 3 and 5 disable op amps A and B
when low. Table II shows different ways to set up the
voltage on these pins.
COMPONENTS
Components that have RF performance similar to the
ones in Table I may be substituted.
R1 and R7 set the I/O impedance, R2 - R6 set the gain,
R8 and C6 set up the disable pin, and C1 - C5 are supply
bypass capacitors. C3 is optional; it adds a bypass
between the supplies, which improves distortion per-
formance for some models. L1 and L2 are ferrite chips
that can reduce interactions with the power supply at
high frequencies; if not desired, they can be replaced
with 0Ω resistors.
CONFIGURATION
R8
C6
External Service
49.9Ω
Open
0Ω
Open
0.1µF
Open
On
Off
TABLE II. Disable Pin—OPA268xN.
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
© 1998 Burr-Brown Corporation
LI-515A
Printed in U.S.A. October, 1999
OPA2680N—Table III shows typical values for this part.
For more information, consult the data sheet.
DUAL SUPPLY
(G = +2)
DUAL SUPPLY SINGLE SUPPLY
COMPONENT
(G = –1)
(G = +1)
R4
R5
R6
Open
0Ω
Open
0Ω
Open
Open
Open
Open
Open
DUAL SUPPLY
(G = +2)
DUAL SUPPLY SINGLE SUPPLY
COMPONENT
(G = –1)
(G = +1)
R1
R2
R3
R4
R5
R6
R7
C1, C2
C3
C4, C5
49.9Ω
178Ω
Open
Open
402Ω
402Ω
49.9Ω
2.2µF
0.01µF
0.1µF
57.6Ω
Open
210Ω
402Ω
Open
402Ω
49.9Ω
2.2µF
0.01µF
0.1µF
49.9Ω
0Ω
TABLE V. OPA2682N Changes.
Open
Open
Open
24.9Ω
49.9Ω
2.2µF
Open
0.1µF
BOARD LAYOUT
This demonstration 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 (or SMB) connectors may be mounted either
vertically or horizontally.
NOTE: The I/O impedances are 50Ω.
TABLE III. OPA2680N.
The location and type of capacitors used for power-supply
bypassing are crucial to high frequency amplifiers. The
tantalum capacitors, C1 and C2, do not need to be as close to
pins 11 and 4 on your PCB and may be shared with other
amplifiers.
OPA2681N—Table IV shows typical values for this part.
To select component values for your op amp (especially R6),
consult its data sheet.
DUAL SUPPLY
(G = +2)
DUAL SUPPLY SINGLE SUPPLY
See the individual op amp data sheet for more information on
proper board layout techniques, and component selection.
COMPONENT
(G = –1)
(G = +1)
R1
R2
R3
R4
R5
R6
R7
C1, C2
C3
C4, C5
49.9Ω
10.0Ω
Open
Open
402Ω
402Ω
49.9Ω
2.2µF
0.01µF
0.1µF
57.6Ω
Open
10.0Ω
402Ω
Open
402Ω
49.9Ω
2.2µF
0.01µF
0.1µF
49.9Ω
10.0Ω
Open
Open
Open
402Ω
49.9Ω
2.2µF
Open
0.1µF
MEASUREMENT TIPS
This demonstration 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.
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
impedance probe must be used, place a 100Ω resistor on the
probe tip to isolate its capacitance from the circuit.
NOTE: The I/O impedances are 50Ω.
TABLE IV. OPA2681N.
OPA2682N—The OPA2682N uses internal resistors to set
the gain at +1, +2 or –1. Use Table IV for the components,
except for the changes in Table V.
(a)
(b)
FIGURE 3. DEM-OPA268xN Demonstration Board Layout; (a) Component Side Silkscreen and Metal, (b) Ground Plane Side
Silkscreen and Metal (bottom view).
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2
DEM-OPA268xN
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