FEATURES

REDUCED BANDWIDTH CHANGE VERSUS GAIN

150MHz BANDWIDTH G = +2

> 90MHz BANDWIDTH TO GAIN > +10

LOW DISTORTION: < –69dBc at 5MHz

HIGH OUTPUT CURRENT: 110mA

SINGLE +5V TO +12V SUPPLY OPERATION

DUAL ±2.5V TO ±6V SUPPLY OPERATION

LOW SUPPLY CURRENT: 0.94mA

LOW SHUTDOWN CURRENT: 100μA

APPLICATIONS

LOW POWER BROADCAST VIDEO DRIVERS

EQUALIZING FILTERS

SAW FILTER HIGH GAIN POST AMPLIFIERS

SHORT LOOP ADSL CO DRIVERS

MULTICHANNEL SUMMING AMPLIFIERS

PROFESSIONAL CAMERAS

ADC INPUT DRIVERS

DESCRIPTION

The OPA683 provides a new level of performance in very lowpower,

wideband, current feedback amplifiers. This CFBplus amplifier

is among the first to use an internally closed-loop input buffer

stage that enhances performance significantly over earlier lowpower

CFB amplifiers. While retaining the benefits of very low

power operation, this new architecture provides many of the

advantages of a more ideal CFB amplifier. The closed-loop input

stage buffer gives a very low and linearized impedance path at the

inverting input to sense the feedback error current. This improved

inverting input impedance gives exceptional bandwidth retention to

much higher gains and improved harmonic distortion over earlier

solutions limited by inverting input linearity. Beyond simple high

gain applications, the OPA683 CFBplus amplifier can allow the gain

setting element to be set with considerable freedom from amplifier

bandwidth interaction. This allows frequency response peaking

elements to be added, multiple input inverting summing circuits to

have greater bandwidth, and low-power line drivers to meet the

demanding requirements of studio cameras and broadcast video.

The output capability for the OPA683 also sets a new mark in

performance for very low-power current feedback amplifiers. Delivering

a full ±4VPP swing on ±5V supplies, the OPA683 also has

the output current to support this swing into a 100Ω load. This

minimal output headroom requirement is complemented by a

similar 1.2V input stage headroom giving exceptional capability for

single +5V operation.

The OPA683’s low 0.94mA supply current is precisely trimmed at

25°C. This trim, along with low shift over temperature and supply

voltage, gives a very robust design over a wide range of operating

conditions. System power may be further reduced by using the

optional disable control pin. Leaving this disable pin open, or holding

it HIGH, gives normal operation. If pulled LOW, the OPA683 supply

current drops to less than 100μA while the I/O pins go to a high

impedance state.