|
|
PDF LT1886 Data sheet ( Hoja de datos )
| Número de pieza | LT1886 | |
| Descripción | Dual 700MHz/ 200mA Operational Amplifier | |
| Fabricantes | Linear Technology | |
| Logotipo |  |
|
Hay una vista previa y un enlace de descarga de LT1886 (archivo pdf) en la parte inferior de esta página. Total 16 Páginas | ||
|
No Preview Available !
LT1886
Dual 700MHz, 200mA
Operational Amplifier
FEATURES
s 700MHz Gain Bandwidth
s ±200mA Minimum IOUT
s Low Distortion: –72dBc at 1MHz, 4VP-P, 25Ω, AV = 2
s Stable in AV ≥ 10, Simple Compensation for AV < 10
s ±4.3V Minimum Output Swing, VS = ±6V, RL = 25Ω
s 7mA Supply Current per Amplifier
s 200V/µs Slew Rate
s Stable with 1000pF Load
s 6nV/√Hz Input Noise Voltage
s 2pA/√Hz Input Noise Current
s 4mV Maximum Input Offset Voltage
s 4µA Maximum Input Bias Current
s 400nA Maximum Input Offset Current
s ±4.5V Minimum Input CMR, VS = ±6V
s Specified at ±6V, ±2.5V
U
APPLICATIO S
s DSL Modems
s xDSL PCI Cards
s USB Modems
s Line Drivers
DESCRIPTIO
The LT®1886 is a 200mA minimum output current dual op
amp with outstanding distortion performance. The ampli-
fiers are gain-of-ten stable, but can be easily compensated
for lower gains. The LT1886 features balanced, high
impedance inputs with 4µA maximum input bias current,
and 4mV maximum input offset voltage. Single supply
applications are easy to implement and have lower total
noise than current feedback amplifier implementations.
The output drives a 25Ω load to ±4.3V with ±6V supplies.
On ±2.5V supplies the output swings ±1.5V with a 100Ω
load. The amplifier is stable with a 1000pF capacitive
load which makes it useful in buffer and cable driver
applications.
The LT1886 is manufactured on Linear Technology’s
advanced low voltage complementary bipolar process and
is available in a thermally enhanced SO-8 package.
, LTC and LT are registered trademarks of Linear Technology Corporation.
TYPICAL APPLICATIO
Single 12V Supply ADSL Modem Line Driver
12V
0.1µF
IN +
10k 20k
+
1/2 LT1886
–
909Ω
12.4Ω
100Ω
1:2*
1µF 10k 20k
1µF 100Ω
909Ω
100Ω
0.1µF
IN –
–
1/2 LT1886
+
12.4Ω
1886 TA01
*COILCRAFT X8390-A
OR EQUIVALENT
ADSL Modem Line Driver Distortion
–60
VS = 12V
AV = 10
f = 200kHz
–70 100Ω LINE
1:2 TRANSFORMER
HD2
–80
–90
HD3
–100
0 2 4 6 8 10 12 14 16
LINE VOLTAGE (VP-P)
1886 TA01a
1
1 page  
LT1886
TYPICAL PERFOR A CE CHARACTERISTICS
Input Bias Current vs
Temperature
3.5
IB = (IB+ + IB–)/2
3.0
2.5
2.0
VS = ±6V
1.5
1.0
VS = ±2.5V
0.5
0
–50 –25
0 25 50 75
TEMPERATURE (°C)
100 125
1886 G04
Input Noise Spectral Density
100
TA = 25°C
AV = 101
100
10
1
10
10
en
in
100 1k 10k
FREQUENCY (Hz)
1
100k
1886 G05
Output Short-Circuit Current vs
Temperature
1000
900 SOURCE, VS = ±6V
800
700
600 SOURCE, VS = ±2.5V
500
SINK, VS = ±6V
400
SINK, VS = ±2.5V
300
200
100 ∆VIN = 0.2V
0
–50 –25
0 25 50 75
TEMPERATURE (°C)
100 125
1886 G06
Output Saturation Voltage vs
Temperature, VS = ±6V
V+
–0.5
RL = 100Ω
–1.0
IL = 150mA IL = 200mA
–1.5
1.5 IL = 150mA IL = 200mA
1.0
RL = 100Ω
0.5
V–
–50 –25
0 25 50 75
TEMPERATURE (°C)
100 125
1886 G07
Output Saturation Voltage vs
Temperature, VS = ±2.5V
V+
–0.5 RL = 100Ω
–1.0
IL = 150mA IL = 200mA
–1.5
1.5 IL = 150mA IL = 200mA
1.0
0.5 RL = 100Ω
V–
–50 –25
0 25 50 75
TEMPERATURE (°C)
100 125
1886 G08
Settling Time vs Output Step
6
VS = ±6V
4
10mV
1mV
2
0
–2
–4
–6
0
10mV
1mV
10 20 30 40 50
SETTLING TIME (ns)
60
1886 G09
Gain and Phase vs Frequency
80 100
70 80
PHASE
VS = ±6V
60 60
50
VS = ±2.5V
40
40 VS = ±6V
30
20
0
20 VS = ±2.5V
–20
10 GAIN
–40
0 TA = 25°C
–10
AV = –10
RL = 100Ω
–20
1M 10M 100M
FREQUENCY (Hz)
–60
–80
–100
1G
1886 G10
Gain Bandwidth vs Supply
Voltage
800
TA = 25°C
AV = –10
700
RL = 1k
600 RL = 100Ω
500 RL = 25Ω
400
Output Impedance vs Frequency
100
10
AV = 100
1
0.1 AV = 10
300
0
2 4 6 8 10 12 14
TOTAL SUPPLY VOLTAGE (V)
1886 G11
0.01
100k
1M 10M
FREQUENCY (Hz)
100M
1886 G12
5
5 Page 
LT1886
APPLICATIO S I FOR ATIO
Figures 3 and 4 can be combined as shown in Figure 5. The
gain is unity at low frequencies, 1 + RF/RG at mid-band and
for stability, a gain of 10 or greater at high frequencies.
Vi
RC
CC
(OPTIONAL)
+
–
RF
Vo = 1 + RF
Vi RG
Vo (RC || RG) ≤ RF/9
1
< 15MHz
2πRCCC
RG
1886 F03
Figure 3. Compensation for Noninverting Gains
+
Vi
–
RF
RG
CC
Vo = 1 (LOW FREQUENCIES)
Vi
VO = 1 + RF (HIGH FREQUENCIES)
RG
RG ≤ RF/9
1
< 15MHz
2πRGCC
1886 F04
Figure 4. Alternate Noninverting Compensation
Vi
RC
CC
RG
CBIG
+
–
RF
Vo
Vo = 1 AT LOW FREQUENCIES
Vi
= 1 + RF AT MEDIUM FREQUENCIES
RG
= 1 + RF
AT HIGH FREQUENCIES
(RC || RG)
1886 F05
Figure 5. Combination Compensation
Output Loading
The LT1886 output stage is very wide bandwidth and able
to source and sink large currents. Reactive loading, even
isolated with a back-termination resistor, can cause ring-
ing at frequencies of hundreds of MHz. For this reason, any
design should be evaluated over a wide range of output
conditions. To reduce the effects of reactive loading, an
optional snubber network consisting of a series RC across
the load can provide a resistive load at high frequency.
Another option is to filter the drive to the load. If a back-
termination resistor is used, a capacitor to ground at the
load can eliminate ringing.
Line Driving Back-Termination
The standard method of cable or line back-termination is
shown in Figure 6. The cable/line is terminated in its
characteristic impedance (50Ω, 75Ω, 100Ω, 135Ω, etc.).
A back-termination resistor also equal to to the
chararacteristic impedance should be used for maximum
pulse fidelity of outgoing signals, and to terminate the line
for incoming signals in a full-duplex application. There are
three main drawbacks to this approach. First, the power
dissipated in the load and back-termination resistors is
equal so half of the power delivered by the amplifier is
wasted in the termination resistor. Second, the signal is
halved so the gain of the amplifer must be doubled to have
the same overall gain to the load. The increase in gain
increases noise and decreases bandwidth (which can also
increase distortion). Third, the output swing of the ampli-
fier is doubled which can limit the power it can deliver to
the load for a given power supply voltage.
+
Vi
–
RF
RG
CABLE OR LINE WITH
CHARACTERISTIC IMPEDANCE RL
RBT
VO
RL
RBT = RL
Vo = 1
Vi 2
(1 + RF/RG)
1886 F06
Figure 6. Standard Cable/Line Back-Termination
An alternate method of back-termination is shown in
Figure 7. Positive feedback increases the effective back-
termination resistance so RBT can be reduced by a factor
of n. To analyze this circuit, first ground the input. As RBT␣ =
RL/n, and assuming RP2>>RL we require that:
Va = Vo (1 – 1/n) to increase the effective value of
RBT by n.
Vp = Vo (1 – 1/n)/(1 + RF/RG)
Vo = Vp (1 + RP2/RP1)
Eliminating Vp, we get the following:
(1 + RP2/RP1) = (1 + RF/RG)/(1 – 1/n)
11
11 Page | ||
| Páginas | Total 16 Páginas | |
| PDF Descargar | [ Datasheet LT1886.PDF ] | |
Hoja de datos destacado
| Número de pieza | Descripción | Fabricantes |
| LT1880 | Picoamp Input Current Precision Op Amp | Linear Technology |
| LT1881 | Dual and Quad Rail-to-Rail Output/ Picoamp Input Precision Op Amps | Linear Technology |
| LT1882 | Dual and Quad Rail-to-Rail Output/ Picoamp Input Precision Op Amps | Linear Technology |
| LT1884 | Dual/Quad Rail-to-Rail Output/ Picoamp Input Precision Op Amps | Linear Technology |
| Número de pieza | Descripción | Fabricantes |
| SLA6805M | High Voltage 3 phase Motor Driver IC. |
 Sanken |
| SDC1742 | 12- and 14-Bit Hybrid Synchro / Resolver-to-Digital Converters. |
 Analog Devices |
|
DataSheet.es es una pagina web que funciona como un repositorio de manuales o hoja de datos de muchos de los productos más populares, |
| DataSheet.es | 2020 | Privacy Policy | Contacto | Buscar |