MAX4142 データシートの表示（PDF） - Maxim Integrated
部品番号
コンポーネント説明
一致するリスト
MAX4142 Datasheet PDF : 12 Pages
| |||
250MHz, Low-Power, High-Output-Current,
Differential Line Driver
_____________________Pin Description
PIN
1, 7
2
3, 5
4
6
8, 14
9
10
11
12
13
NAME
VEE
IN+
N.C.
SHDN
IN-
VCC
OUT-
SENSE-
GND
SENSE+
OUT+
FUNCTION
Negative Power Supply. Connect VEE
to -5V.
Noninverting Input
No Connect. Not internally connected.
Logic Input for Shutdown Circuitry. A
logic low enables the amplifier. A logic
high disables the amplifier.
Inverting Input
Positive Power Supply. Connect VCC
to +5V.
Inverting Output
Inverting Output Sense. Connect to OUT-
close to the pin for normal operation.
Ground
Noninverting Output Sense. Connect
to OUT+ close to the pin for normal
operation.
Noninverting Output
IN+
MAX4142
A1
OUT+
RF
RG
VIN
A3
RG
RF
A2
IN-
SENSE+
GND
( ) VOUT =
1
+
RF
RG
VIN
SENSE-
OUT-
Figure 1. MAX4142 Functional Diagram
Detailed Description
The MAX4142 differential line driver features 250MHz
bandwidth and 67dB common-mode rejection (CMR) at
10MHz. This part achieves a 1400V/µs slew rate, and
power dissipation is only 125mW. The MAX4142 has an
internally set +2V/V closed-loop gain, making it ideal as
a back-terminated line driver. The output stage can
drive ±6V into a 100Ω load.
The MAX4142 utilizes a three-amplifier topology to pro-
vide differential inputs/outputs and common-mode
feedback (Figure 1), making it ideal for applications
with high common-mode noise, such as for driving T1
or xDSL transmissions over a twisted-pair cable. The
MAX4142’s differential noninverting structure uses two
noninverting amplifiers (A1 and A2) to provide a single
device with differential inputs and outputs. The use of
two amplifiers effectively doubles the output voltage
swing and bandwidth, and improves slew rate when
compared to the single op-amp differential amplifier.
Excellent gain and phase, along with low noise, also
make the MAX4142 suitable for video applications and
RF-signal processing.
For a complete differential transmission link, use the
MAX4142 line driver with the MAX4144/MAX4146 line
receivers, as shown in the Typical Application Circuit.
Applications Information
Balanced Transmission Lines
Differential (balanced) transmission lines use two con-
ductors to transmit high-speed signals over low-cost
cable or twisted-pair wire with minimal signal degrada-
tion. The transmit side of the balanced transmission line
is driven by an amplifier with differential outputs, while
the signal is received by an amplifier with differential
inputs. In an ideal balanced system, each conductor
has the same impedance from input to output and from
the conductor to the system ground. Since the imped-
ance from each conductor to ground is equivalent, any
noise or other interference coupled into the transmis-
sion line will be equal in magnitude in each conductor,
appearing as a common-mode signal to the amplifier at
the receiving end of the transmission line. Since the
receiving amplifier subtracts the signals on each side
of the transmission line to obtain the desired informa-
tion, common-mode signals are effectively canceled
out by the receiving amplifier.
Common-Mode Feedback
In nonideal balanced systems, impedance mismatches
between the conductors of a transmission line can
degrade system common-mode rejection (CMR) by
converting a portion of any common-mode signal to a
6 _______________________________________________________________________________________
Share Link: 