Single-Supply, 150MHz, 16-Bit Accurate,

Ultra-Low Distortion Op Amps

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Detailed Description

The MAX4434–MAX4437 are wide-bandwidth, ultra-low-

distortion, voltage-feedback amplifiers. The MAX4434/

MAX4436 are internally compensated for unity gain.

The MAX4435/MAX4437 are internally compensated for

gains of +5V/V or greater.

These amplifiers have ultra-fast 35ns (MAX4434/

MAX4436) 16-bit settling times, -97dB SFDR at 1MHz,

and 4Vp-p output swing with minimum 115dB open-

loop gain.

High-Speed ADC Input Driver Application

The MAX4434–MAX4437 op amps are ideal for driving

high-speed 14- to 16-bit ADCs. In most cases, these

ADCs operate with a charge balance scheme, with

capacitive loads internally switched on and off from the

input. The driver used must withstand these changing

capacitive loads while holding the signal amplitude sta-

bility consistent with the ADC’s resolution and, at the

same time, have a frequency response compatible with

the sampling speed of the ADC (Figure 1).

Inverting and Noninverting Configurations

The circuits typically used for the inverting and non-

inverting configurations of the MAX4434–MAX4437 are

shown in Figures 2a and 2b. The minimum uncondition-

ally stable gain values are 1 for the MAX4434/MAX4436

and 5 for the MAX4435/MAX4437. Use care in selecting

dynamic stability considerations (based on the part’s fre-

quency response and the input capacitance of the

MAX4434–MAX4437), the maximum recommended

yield a higher bandwidth and better dynamic stability, at

the cost of higher power consumption, higher power dis-

sipation in the IC, and reduced output drive availability.

and must be discounted from the maximum output cur-

rent to calculate the maximum current available to the

If DC thermal stability is an important design concern,

the Thevenin resistance seen by both inputs at DC

must be balanced. This includes the resistance of the

signal source and termination resistors if the amplifier

signal input is fed from a transmission line. The capaci-

tance associated with the feedback resistors must also

be considered as a possible limitation to the available

bandwidth or to the dynamic stability. Only resistors

with small parallel capacitance specifications should

be considered.

Applications Information

Layout and Power-Supply Bypassing

The MAX4434–MAX4437 have wide bandwidth and

consequently require careful board layout. To realize

the full AC performance of these high-speed amplifiers,

pay careful attention to power-supply bypassing and

board layout. The PC board should have a large low-

impedance ground plane that is as free of voids as

possible. Do not use commercial breadboards. Keep

signal lines as short and straight as possible. Observe

high-frequency bypassing techniques to maintain the

amplifier’s accuracy and stability. In general, use sur-

HIGH-SPEED

14/16-BIT ADC

Figure 1. Typical Application Circuit

=

A = 1 +

Figure 2a. Noninverting Configuration

=

A =

Figure 2b. Inverting Configuration