Setting Gain

The MAX4448/MAX4449 are stable with minimum gain

of +2V/V and +5V/V, respectively. An external resistor,

RGAIN, connected between RG and GND sets the gain

of these devices. Calculate the gain as follows:

Gain = 2 (1 + 300 / RGAIN)

RGAIN for the MAX4449 must be

≤200Ω.

Driving Capacitive Loads

The MAX4447/MAX4448/MAX4449 are designed to

drive capacitive loads. However, excessive capacitive

loads may cause ringing or instability at the output as

phase margin is reduced. Adding a small series isola-

tion resistor at the output helps reduce the ringing but

slightly increases gain error.

Twisted-Pair Line Driver

The MAX4447/MAX4448/MAX4449 are well-suited to

drive twisted-pair cables. The 24AWG telephone wire

widely used produces losses at the higher frequencies.

Compensate for these losses by increasing the gain

slightly.

6500V/µs, Wideband, High-Output-Current, Single-

Ended-to-Differential Line Drivers with Enable

______________________________________________________________________________________

11

IN

500mV/div

OUT

1V/div

CL = 15pF

IN

500mV/div

OUT

1V/div

CL = 15pF

Figure 3. Capacitive-Loaded Output Step Response Without

Isolation Resistor

Figure 4. Capacitive-Loaded Output Step Response with 14

Ω

Isolation Resistor

Chip Information

TRANSISTOR COUNT: 291