OPA4684M Datasheet, PDF (1/32 Pages) Texas Instruments – QUAD LOW-POWER CURRENT-FEEDBACK OPERATIONAL AMPLIFIER

features
D Minimal Bandwidth Change Versus Gain
D 170-MHz Bandwidth at G = +2
D > 120 MHz Bandwidth To Gain > +10
D Low Distortion: < −78 dBc at 5 MHz
D High Output Current: 120 mA
D Single 5-V to 12-V Supply Operation
D Dual ±2.5 to ±6.0V Supply Operation
D Low Supply Current: 6.8 mA Total
OPA4684M
QUAD LOWĆPOWER CURRENTĆFEEDBACK
OPERATIONAL AMPLIFIER
SGLS145B − AUGUST 2003 − REVISED FEBRUARY 2004
applications
D Low-Power Broadcast Video Drivers
D Equalizing Filters
D Saw Filter High-Gain Post Amplifiers
D Multichannel Summing Amplifiers
D Wideband Differential Channels
D Analog-to-Digital Converters (ADC) Input
Drivers
D Multiple Pole Active Filters
D OPA4658 Low-Power Upgrade
description
The OPA4684 provides a new level of performance in low-power, wideband, current-feedback (CFB) amplifiers.
This CFB_PLUS amplifier is among the first to use an internally closed-loop input buffer stage that enhances
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
applications, the OPA4684 CFB_PLUS amplifier permits 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 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.
V+
1 of 4 Channels
CFB_PLUS BW (MHz) vs Gain
VO
V−
IERR
Z(S)IERR
RF
RG
Low Power CFB_PLUS Amplifer
Patent Pending
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.
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.
Copyright  2003− 2004 Texas Instruments Incorporated
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