OPA4684M

QUAD LOW POWER CURRENT FEEDBACK

OPERATIONAL AMPLIFIER

SGLS145B − AUGUST 2003 − REVISED FEBRUARY 2004

1

POST OFFICE BOX 655303

features

applications

Drivers

description

The OPA4684 provides a new level of performance in low-power, wideband, current-feedback (CFB) amplifiers.

performance significantly over earlier low-power CFB amplifiers. While retaining the benefits of very low power

operation, this new architecture provides many of the benefits 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 retains exceptional bandwidth to much higher gains and

improves harmonic distortion over earlier solutions limited by inverting input linearity. Beyond simple high-gain

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 of the OPA4684 also sets a new mark in performance for low-power current-feedback

amplifiers. Delivering a full

±4Vp-p swing on ±5V supplies, the OPA4684 also has the output current to support

>

±3-V swing into 50 Ω. This minimal output headroom requirement is complemented by a similar 1.2-V input

stage headroom giving exceptional capability for single +5V operation.

The OPA4684’s low 6.8-mA 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.

Low Power CFBPLUS Amplifer

1 of 4 Channels

Z(S)IERR

VO

RF

IERR

V−

V+

RG

Patent Pending

CFBPLUS BW (MHz) vs Gain

Copyright

 2003− 2004 Texas Instruments Incorporated

PRODUCTION DATA information is current as of publication date.

Products conform to specifications per the terms of Texas Instruments

standard warranty. Production processing does not necessarily include

testing of all parameters.

Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of

Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.