Parameters that vary significantly over supply voltage or
temperature are shown in the “Typical Characteristics” sec-
tion of this data sheet.
APPLICATIONS INFORMATION
The OPAx356 series is a CMOS, high-speed, voltage feed-
back, operational amplifier designed for video and other
general-purpose applications. It is available as a single or
dual op amp.
OUTPUT DRIVE
The OPAx356 output stage is capable of driving a standard
back-terminated 75Ω video cable. By back-terminating a
transmission line, it does not exhibit a capacitive load to its
driver. A properly back-terminated 75Ω cable does not ap-
pear as capacitance; it presents only a 150Ω resistive load to
the OPAx356 output.
The amplifier features a 200MHz gain bandwidth and
360V/µs slew rate, but it is unity-gain stable and can be
operated as a +1V/V voltage follower.
Its input common-mode voltage range includes ground, al-
lowing the OPAx356 to be used in virtually any single-supply
application up to a supply voltage of +5.5V.
The output stage can supply high short-circuit current (typi-
cally over 200mA). Therefore, an on-chip thermal shutdown
circuit is provided to protect the OPAx356 from dangerously
high junction temperatures. At 160°C, the protection circuit
will shut down the amplifier. Normal operation will resume
when the junction temperature cools to below 140°C.
PCB LAYOUT
Good high-frequency PC board layout techniques should be
employed for the OPAx356. Generous use of ground planes,
short direct signal traces, and a suitable bypass capacitor
located at the V+ pin will assure clean, stable operation.
Large areas of copper also provide a means of dissipating
heat that is generated within the amplifier in normal opera-
tion.
NOTE: It is not recommended to run a continuous DC current
in excess of ±60mA. Refer to the graph of “Output Voltage
Swing vs Output Current”, shown in the “Typical Character-
istics” section of this data sheet.
Sockets are definitely not recommended for use with any
high-speed amplifier.
INPUT AND ESD PROTECTION
A 10µF ceramic bypass capacitor is the minimum recom-
mended value; adding a 1µF or larger tantalum capacitor in
parallel can be beneficial when driving a low-resistance load.
Providing adequate bypass capacitance is essential to achiev-
ing very low harmonic and intermodulation distortion.
All OPAx356 pins are static protected with internal ESD
protection diodes tied to the supplies, as shown in Figure 1.
These diodes will provide overdrive protection if the current
is externally limited to 10mA by the source or by a resistor.
OPERATING VOLTAGE
+VCC
The OPAx356 is specified over a power-supply range of
+2.7V to +5.5V (±1.35 to ±2.75V). However, the supply
voltage may range from +2.5V to +5.5V (±1.25V to ±2.75V).
Supply voltages higher than 7.5V (absolute maximum) can
permanently damage the amplifier.
External
Pin
Internal
Circuitry
–VCC
FIGURE 1. Internal ESD Protection.
OPA356, 2356
10
SBOS212A