
OPA687
OPA687
1998 Burr-Brown Corporation
PDS-1372C
Wideband, Ultra-Low Noise,
Voltage Feedback OPERATIONAL AMPLIFIER
With Power Down
FEATURES
G
HIGH GAIN BANDWIDTH: 3.8GHz
G
LOW INPUT VOLTAGE NOISE: 0.95nV/
√
Hz
G
VERY LOW DISTORTION: –95dBc (5MHz)
G
LOW DISABLED POWER: 2mW
G
VERY HIGH SLEW RATE: 900V/
μ
s
G
STABLE FOR G
≥
12
DESCRIPTION
The OPA687 combines a very high gain bandwidth and
large signal performance with an ultra-low input noise
voltage (0.95nV/
√
Hz) while dissipating only 18mA sup-
ply current. Where power savings is paramount, the
OPA687 also includes an optional power down pin that,
when pulled low, will disable the amplifier and decrease
the quiescent current to only 1% of its powered up value.
This optional feature may be left disconnected to insure
normal amplifier operation when no power-down is re-
quired.
The combination of low input voltage and current noise,
along with a 3.8GHz gain bandwidth product, make the
OPA687 an ideal amplifier for wideband transimpedance
APPLICATIONS
G
LOW DISTORTION ADC DRIVER
G
OC-3 FIBER OPTIC RECEIVER
G
LOW NOISE DIFFERENTIAL AMPLIFIERS
G
EQUALIZING RECEIVERS
G
ULTRASOUND CHANNEL AMPLIFIERS
G
IMPROVED REPLACEMENT FOR THE
CLC425
TM
stages. As a voltage gain stage, the OPA687 is opti-
mized for a flat frequency response at a gain of +20 and
is guaranteed stable down to gains of +12. New external
compensation techniques allows the OPA687 to be used
at any inverting gain with excellent frequency response
control. Using this compensation can give an extremely
high dynamic range ADC driver to support > 40MSPS
12- and 14-bit converters.
Ultra-High Dynamic Range
Differential Input ADC Driver
+5V
–5V
OPA687
+5V
+5V
–5V
850
39pF
OPA687
1.7pF
80pF
V
IN
+
V
IN
–
80pF
1.7pF
850
39pF
100
20
20
1:2
50
Source
< 6dB
Noise
Figure
ADS852
14-Bit
65MSPS
100
V
CM
V
CM
OPA687
IInternational 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 In
Center Frequency (MHz)
3
0
–60
–65
–70
–75
–80
–85
5
10
15
20
25
30
35
40
45
50
4Vp-p
2Vp-p
Measured 2-Tone, 3rd-Order Distortion for
Differential ADC Driver.
OPA687 RELATED PRODUCTS
INPUT NOISE
VOLTAGE (nV/
√
Hz)
GAIN BANDWIDTH
PRODUCT (MHz)
SINGLES
DUAL
OPA642
OPA643
OPA686
2.7
2.3
1.3
210
800
1600
OPA2686
For most current data sheet and other product
information, visit www.burr-brown.com