BB OPA63XU

DEM-OPA68xU
®
EVALUATION FIXTURE
DESCRIPTION
The DEM-OPA68xU demonstration board is an
unpopulated printed circuit board (PCB) for BurrBrown’s high speed single op amps available in SO-8
packages. Figure 1 shows the pin out used for most of
these op amps. Table I lists the exceptions to this pin-out
that are also supported by this board. For more information on these op amps, and good PCB layout techniques,
see the individual data sheets.
1
8
NC
–In
2
7
+VS
+In
3
6
Output
–VS
4
5
NC
PIN #5
PIN #8
OPA63xU
OPA64xU
OPA628U
OPA680U
OPA681U
OPA682U
OPA686U
OPA688U
OPA689U
—
—
—
—
—
RG
—
—
—
—
–VS (optional)
–VS
—
—
—
—
VL
VL
DIS
+VS (optional)
+VS
DIS
DIS
DIS
DNC(1)
VH
VH
TABLE I. Supported Exceptions to Pinout in Figure 1.
CIRCUIT
The circuit schematic in Figure 2 shows the connections for all possible components. Each model will
only use some of the components.
SO-8
NC
PIN #2
NOTE: (1) DNC means do not connect.
The ordering number for this board is MKT-351. Limit
of 5 per customer.
Top View
PRODUCT
COMPONENTS
Components that have RF performance similar to the
ones in Table II may be substituted. C1 and C2 need a
larger voltage rating for ±15V dual supplies.
FIGURE 1. Pin Configuration for OPA6xxU.
J3
R10
VH/DIS/DIS
R9
R3
R2
J1
IN
R4
R1
R8
C7
C5
8
3
7
2
R5
5
1
J2
Out
4
C4
C6
R12
R7
6
R6
L2
R11
P1
–VS
C3
J4
+ C2
GND
L1
R13
VL
+
+VS
C1
FIGURE 2. Circuit Schematic for DEM-OPA68xU.
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-513A
Printed in U.S.A. November, 1999
PART
DESCRIPTION
C1, C2
Tantalum Chip Capacitor, SMD EIA size 3528, 20V
C3 - C7
Multi-Layer Ceramic Chip Cap., SMD 1206, 50V
J1 - J4
SMA or SMB Board Jack (Amphenol 901-144-8)
L1, L2
EMI-Suppression Ferrite Chip, SMD 1206
(Steward LI 1206 B 900 R)
P1
Terminal Block, 3.5mm centers
(On-Shore Technology ED555/3DS)
R1 - R13
Metal Film Chip Resistor, SMD 1206, 1/8W
TABLE II. Component Descriptions.
R1 and R7 set the I/O impedance, R2 - R6 set the gain, and C1
- C5 are supply bypass capacitors. C3 is optional; it adds a
bypass between the supplies, which improves distortion
performance 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. R8 - R13, C6 and C7 are optional components that
support op amps with special functions (see Table I).
COMPONENT
SINGLE SUPPLY
(G = +1)
R1
R2
R3
R4
R5
R6
R7
R8 - R13
C1
C2
C3
C4
C5
C6, C7
49.9Ω
10.0Ω
Open
Open
402Ω
402Ω
49.9Ω
Open
2.2µF
2.2µF
0.01µF
0.1µF
0.1µF
Open
57.6Ω
Open
10.0Ω
402Ω
Open
402Ω
49.9Ω
Open
2.2µF
2.2µF
0.01µF
0.1µF
0.1µF
Open
49.9Ω
10.0Ω
Open
Open
Open
402Ω
49.9Ω
Open
2.2µF
Open
Open
0Ω
0.1µF
Open
DUAL SUPPLY
(G = –1)
SINGLE SUPPLY
(G = +1)
R1
R2
R3
R4
R5
R6
R7
R8 - R13
C1
C2
C3
C4
C5
C6, C7
49.9Ω
178Ω
Open
Open
402Ω
402Ω
49.9Ω
Open
2.2µF
2.2µF
0.01µF
0.1µF
0.1µF
Open
57.6Ω
Open
210Ω
402Ω
Open
402Ω
49.9Ω
Open
2.2µF
2.2µF
0.01µF
0.1µF
0.1µF
Open
49.9Ω
0Ω
Open
Open
Open
24.9Ω
49.9Ω
Open
2.2µF
Open
Open
0Ω
0.1µF
Open
TABLE IV. Standard Voltage-Feedback Op Amps.
Standard Current-Feedback Op Amps—These op amps
have the pinout shown in Figure 1. Table III shows typical
values used for these parts. To select component values for
your op amp (especially R6), consult its data sheet.
DUAL SUPPLY
(G = –1)
DUAL SUPPLY
(G = +2)
NOTE: The values and gains shown will not work for all voltage-feedback op
amps. See the individual op amp data sheet to select proper values. The I/O
impedances are 50Ω.
For single supply operation, do not connect L2; otherwise,
the –VS input to P1 would be at ground potential.
DUAL SUPPLY
(G = +2)
COMPONENT
COMPONENT
DUAL SUPPLY
(G = )+2
DUAL SUPPLY
(G = –1)
SINGLE SUPPLY
(G = +1)
R8, R11
C1
C2
C4, C6
C5, C7
0Ω
4.7µF
4.7µF
0.1µF
0.1µF
0Ω
4.7µF
4.7µF
0.1µF
0.1µF
0Ω
4.7µF
Open
0Ω
0.1µF
TABLE V. OPA628U and OPA64xU Changes.
OPA63xU—Pin 8 disables the output when high (OPA632
and OPA635). Table VII shows different ways to set up pin
8’s voltage using R8, R9 and C7. Use Table IV for the other
components, except for the changes shown in Table VI; note
these are all single supply configurations.
COMPONENT
SINGLE SUPPLY SINGLE SUPPLY SINGLE SUPPLY
(G = +2)
(G = –1)
(G = +1)
C4
0Ω
0Ω
0Ω
TABLE VI. OPA63xU Changes.
NOTE: The values and gains shown will not work for all current-feedback op
amps. See the data sheet to select proper values. The I/O impedances are 50Ω.
TABLE III. Standard Current-Feedback Op Amps.
CONFIGURATION
R8
C9
External Source
On
Off
Open
Open
0Ω
49.9Ω
0Ω
Open
TABLE VII. Disable Pin—OPA632U and OPA635U.
Standard Voltage-Feedback Op Amps—These op amps
have the pinout shown in Figure 1. Table IV shows typical
values used for these parts. To select component values for
your op amp, consult its data sheet.
OPA680U—Pin 8 disables the output when low. Table VIII
shows different ways to set up pin 8’s voltage using R8, R9
and C7. Use Table IV for the other components.
OPA628U and OPA64xU—These op amps have additional
supply pins (see Table I) to improve distortion. Use the
values in Table IV, except for the changes shown in Table
V (the OPA64xP family will function without these changes,
but with reduced distortion performance).
CONFIGURATION
R8
R9
C7
External Source
On
Off
Open
Open
Open
49.9Ω
Open
0Ω
Open
0.1µF
Open
TABLE VIII. Disable Pin—OPA68xU.
®
DEM-OPA68xU
2
OPA689U—This VLA™ is the high gain-stable version of
the OPA688U. Set up this op amp the same as the OPA688U,
except for the changes shown in Table XII.
OPA681U—Pin 8 disables the output when low. Table VIII
shows different ways to set up pin 8’s voltage using R8, R9
and C7. Use Table III for the other components.
OPA682U—The OPA682U uses internal resistors to set the
gain at +1, +2, or –1. Pin 8 disables the output when low.
Table VIII shows different ways to set up pin 8’s voltage
using R8, R9 and C7. Use Table III for the other components,
except for the changes shown in Table IX.
COMPONENT
DUAL SUPPLY
(G = +2)
DUAL SUPPLY
(G = –1)
SINGLE SUPPLY
(G = +1)
R4
R5
R6
Open
0Ω
Open
0Ω
Open
Open
Open
Open
Open
DUAL SUPPLY
(G = –10)
SINGLE SUPPLY
(G = +20)
R1
R2
R3
R4
R5
R6
49.9Ω
20.0Ω
Open
Open
49.9Ω
453Ω
Open
Open
10.0Ω
49.9Ω
Open
499Ω
49.9Ω
10.0Ω
Open
Open
26.1Ω
499Ω
DUAL SUPPLY
(G = –6)
SINGLE SUPPLY
(G = +6)
R1
R2
R3
R4
R5
R6
49.9Ω
100Ω
Open
Open
150Ω
750Ω
82.5Ω
Open
130Ω
124Ω
Open
750Ω
49.9Ω
100Ω
Open
Open
150Ω
750Ω
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.
OPA686U—Use Table X for the higher gains needed by
this part, and Table IV for the other component values. Extra
care is needed to ensure pin 8 is not connected (see Table I).
DUAL SUPPLY
(G = +10)
DUAL SUPPLY
(G = +6)
TABLE XII. OPA689U Changes.
TABLE IX. OPA682U Changes.
COMPONENT
COMPONENT
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 7 and 4 on your PCB, and may be shared with other
amplifiers.
See the individual op amp data sheet for more information
on proper board layout techniques, and component selection.
TABLE X. OPA686U Changes.
OPA688U—This VLA™ (Voltage Limiting Amplifier) has
two inputs (VH and VL in Table I), which limit the output
voltage swing. Table XI shows different ways to set up pin
5’s and pin 8’s voltages using R8 - R13 and C5 - C7. Use
Table IV for the other components.
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. Change the component
values for different input and output impedance levels.
Note that this board would require modification for the
single-supply circuit shown in the OPA688 data sheet. In
dual supply applications, using R10 instead of R8 makes VH
negative, and using R13 instead of R11 makes VL positive.
COMPONENT
DUAL SUPPLY
(G = +2)
DUAL SUPPLY
(G = –1)
SINGLE SUPPLY
(G = +1)
R8
R9
R11
R12
R13
C5 - C7
3.01kΩ
1.91kΩ
3.01kΩ
1.91kΩ
Open
0.1µF
3.01kΩ
1.91kΩ
3.01kΩ
1.91kΩ
Open
0.1µF
549Ω
1.58kΩ
Open
549Ω
1.58kΩ
0.1µF
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.
TABLE XI. Limiting Pins—OPA68xU.
®
3
DEM-OPA68xU
(a)
(b)
FIGURE 3. DEM-OPA68xU Demonstration Board Layout; (a) Component Side Silkscreen and Metal, (b) Ground Plane Side
Silkscreen and Metal (bottom view).
®
DEM-OPA68xU
4