MAX4447 Maxim, MAX4447 Datasheet - Page 11

• Manufacturer Part Number: MAX4447
• Description: The MAX4447/MAX4448/MAX4449 single-ended-to-differential line drivers are designed for high-speed communications
• Manufacturer: Maxim

The MAX4448/MAX4449 are stable with minimum gain
of +2V/V and +5V/V, respectively. An external resistor,
R
of these devices. Calculate the gain as follows:
R
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.
Figure 3. Capacitive-Loaded Output Step Response Without
Isolation Resistor
6500V/µs, Wideband, High-Output-Current, Single-
GAIN
GAIN
, connected between RG and GND sets the gain
for the MAX4449 must be ≤200Ω.
500mV/div
1V/div
Ended-to-Differential Line Drivers with Enable
OUT
IN
Gain = 2 (1 + 300 / R
______________________________________________________________________________________
Driving Capacitive Loads
GAIN
C
)
L
Setting Gain
= 15pF
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.
Figure 4. Capacitive-Loaded Output Step Response with 14Ω
Isolation Resistor
TRANSISTOR COUNT: 291
500mV/div
1V/div
OUT
IN
Twisted-Pair Line Driver
Chip Information
C
L
= 15pF
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