Datasheet LT1221 (Analog Devices) - 7
| Fabricante | Analog Devices |
| Descripción | 150MHz, 250V/µs, AV ≥ 4 Operational Amplifier |
| Páginas / Página | 12 / 7 — APPLICATIONS INFORMATION. Compensation. Capacitive Loading. SI PLIFIED … |
| Formato / tamaño de archivo | PDF / 261 Kb |
| Idioma del documento | Inglés |
APPLICATIONS INFORMATION. Compensation. Capacitive Loading. SI PLIFIED SCHE ATIC
Línea de modelo para esta hoja de datos
Versión de texto del documento
LT1221
U U W U APPLICATIONS INFORMATION
offset current have identical specifications. For this reason,
Compensation
matching the impedance on the inputs to reduce bias The LT1221 has a typical gain-bandwidth product of current errors is not necessary. 150MHz which allows it to have wide bandwidth in high gain configurations (i.e., in a gain of 10, it will have a
Capacitive Loading
bandwidth of about 15MHz). The amplifier is stable in a The LT1221 is stable with capacitive loads. This is accom- noise gain of 4 so the ratio of the signal at the inverting input plished by sensing the load induced output pole and adding to the output must be 1/4 or less. Straightforward gain compensation at the amplifier gain node. As the capacitive configurations of 4 or –3 are stable, but there are several load increases, both the bandwidth and phase margin others that allow the amplifier to be stable for lower signal decrease. There will be peaking in the frequency domain as gains (the noise gain, however, remains 4 or more). One shown in the curve of Frequency Response vs Capacitive example is the summing amplifier on the first page of this Load. The small-signal transient response will have more data sheet. Each input signal has a gain of –1 to the output, overshoot as shown in the photo of the small-signal but it is easily seen that this configuration is equivalent to response with 1000pF load. The large-signal response with a gain of –3 as far as the amplifier is concerned. Another a 10,000pF load shows the output slew rate being limited circuit is shown below with a DC gain of 1, but an AC gain to 4V/µs by the short-circuit current. The LT1221 can drive of 5. The break frequency of the R-C combination across coaxial cable directly, but for best pulse fidelity a resistor of the amplifier inputs should be approximately a factor of 10 value equal to the characteristic impedance of the cable less than the gain-bandwidth of the amplifier divided by the (i.e., 75Ω) should be placed in series with the output. The high frequency gain (in this case 1/10 of 150MHz/5 or other end of the cable should be terminated with the same 3MHz). value resistor to ground.
W W SI PLIFIED SCHE ATIC
V+ 7 NULL 1 8 BIAS 1 BIAS 2 6 OUT +IN 3 2 –IN V – 4 LT1221 • SS 7
U U W U APPLICATIONS INFORMATION
offset current have identical specifications. For this reason,
Compensation
matching the impedance on the inputs to reduce bias The LT1221 has a typical gain-bandwidth product of current errors is not necessary. 150MHz which allows it to have wide bandwidth in high gain configurations (i.e., in a gain of 10, it will have a
Capacitive Loading
bandwidth of about 15MHz). The amplifier is stable in a The LT1221 is stable with capacitive loads. This is accom- noise gain of 4 so the ratio of the signal at the inverting input plished by sensing the load induced output pole and adding to the output must be 1/4 or less. Straightforward gain compensation at the amplifier gain node. As the capacitive configurations of 4 or –3 are stable, but there are several load increases, both the bandwidth and phase margin others that allow the amplifier to be stable for lower signal decrease. There will be peaking in the frequency domain as gains (the noise gain, however, remains 4 or more). One shown in the curve of Frequency Response vs Capacitive example is the summing amplifier on the first page of this Load. The small-signal transient response will have more data sheet. Each input signal has a gain of –1 to the output, overshoot as shown in the photo of the small-signal but it is easily seen that this configuration is equivalent to response with 1000pF load. The large-signal response with a gain of –3 as far as the amplifier is concerned. Another a 10,000pF load shows the output slew rate being limited circuit is shown below with a DC gain of 1, but an AC gain to 4V/µs by the short-circuit current. The LT1221 can drive of 5. The break frequency of the R-C combination across coaxial cable directly, but for best pulse fidelity a resistor of the amplifier inputs should be approximately a factor of 10 value equal to the characteristic impedance of the cable less than the gain-bandwidth of the amplifier divided by the (i.e., 75Ω) should be placed in series with the output. The high frequency gain (in this case 1/10 of 150MHz/5 or other end of the cable should be terminated with the same 3MHz). value resistor to ground.
W W SI PLIFIED SCHE ATIC
V+ 7 NULL 1 8 BIAS 1 BIAS 2 6 OUT +IN 3 2 –IN V – 4 LT1221 • SS 7