1998 Burr-Brown Corporation
LI-515A
Printed in U.S.A. October, 1999
DEM-OPA268xN
EVALUATION FIXTURE
DESCRIPTION
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.
The ordering number for this board is MKT-353. Limit
of 5 per customer.
FIGURE 2. Circuit Schematic for DEM-OPA268xN.
PART
DESCRIPTION
C
1
, C
2
Tantalum Chip Capacitor, SMD EIA size 3528, 20V
C
3
- C
6B
Multi-Layer Ceramic Chip Cap., SMD 1206, 50V
J
1A
- J
3B
SMA or SMB Board Jack (Amphenol 901-144-8)
L
1
, L
2
EMI-Suppression Ferrite Chip, SMD 1206
(Steward LI 1206 B 900 R)
P
1
Terminal Block, 3.5mm centers
(On-Shore Technology ED555/3DS)
R
1A
- R
8B
Metal Film Chip Resistor, SMD 1206, 1/8W
TABLE I. Part Descriptions.
TABLE II. Disable Pin—OPA268xN.
For single supply operation, do not connect L
2
; other-
wise, the –V
S
input to P
1
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.
Top View
SO-14
1
2
3
4
5
6
7
14
13
12
11
10
9
8
–In A
+In A
DIS A
–V
S
DIS B
+In B
–In B
Out A
NC
NC
+V
S
NC
NC
Out B
FIGURE 1. Pin Configuration.
CIRCUIT
The circuit schematic in Figure 2 shows the connec-
tions for all possible components. Each model will
only use some of the components.
COMPONENTS
Components that have RF performance similar to the
ones in Table I may be substituted.
R
1
and R
7
set the I/O impedance, R
2
- R
6
set the gain,
R
8
and C
6
set up the disable pin, and C
1
- C
5
are supply
bypass capacitors. C
3
is optional; it adds a bypass
between the supplies, which improves distortion per-
formance for some models. L
1
and L
2
are ferrite chips
that can reduce interactions with the power supply at
high frequencies; if not desired, they can be replaced
with 0
resistors.
CONFIGURATION
R
8
C
6
External Service
On
Off
49.9
Open
0
Open
0.1
μ
F
Open
R
4A
R
2A
R
3A
R
7A
Out A
J
2A
GND
+V
S
–V
S
P
1
2
3
C
6A
5
4
11
14
1
C
3
R
8A
C
2
R
1A
IN A
J
1A
R
5A
R
6A
R
6B
+
L
2
L
1
C
1
+
R
4B
R
2B
R
3B
R
7B
Out B
6
8
7
R
1B
IN B
R
5B
C
6B
C
4
C
5
DIS A
J
3A
R
8B
DIS B
J
3B
J
2B
J
1B
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