Datasheet LT1210 (Analog Devices) - 10
| Manufacturer | Analog Devices |
| Description | 1.1A, 35MHz Current Feedback Amplifier |
| Pages / Page | 20 / 10 — APPLICATIONS INFORMATION. Figure 2. Shutdown Interface. (a) AV = –1. (b) … |
| Revision | C |
| File Format / Size | PDF / 1.3 Mb |
| Document Language | English |
APPLICATIONS INFORMATION. Figure 2. Shutdown Interface. (a) AV = –1. (b) AV = 2. Figure 4. Large-Signal Response vs I. Slew Rate
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APPLICATIONS INFORMATION
15V quiescent current can be reduced to 9mA in the inverting configuration without much change in response. In non- VIN + inverting mode, however, the slew rate is reduced as the LT1210 VOUT quiescent current is reduced. –SD RF –15V 5V 74C906 24kΩ RG ENABLE 15V 1210 F02
Figure 2. Shutdown Interface
resistor speeds up the turn-off time and ensures that the LT1210 is completely turned off. Because the pin is referenced to the positive supply, the logic used should R 1210 F04a F = 750Ω IQ = 9mA, 18mA, 36mA have a breakdown voltage of greater than the positive RL = 10Ω VS = ±15V supply voltage. No other circuitry is necessary as the
(a) AV = –1
internal circuit limits the Shutdown pin current to about 500µA. Figure 3 shows the resulting waveforms. VOUT ENABLE R 1210 F04b F = 750Ω IQ = 9mA, 18mA, 36mA RL = 10Ω VS = ±15V
(b) AV = 2
A 1210 F03 V = 1 RPULL-UP = 24k
Figure 4. Large-Signal Response vs I
R
Q
F = 825Ω VIN = 1VP-P RL = 50Ω VS = ±15V
Slew Rate Figure 3. Shutdown Operation
Unlike a traditional op amp, the slew rate of a current feedback amplifier is not independent of the amplifier gain For applications where the full bandwidth of the amplifier configuration. There are slew rate limitations in both the is not required, the quiescent current of the device may be input stage and the output stage. In the inverting mode, reduced by connecting a resistor from the Shutdown pin and for higher gains in the noninverting mode, the signal to ground. The quiescent current will be approximately 65 amplitude on the input pins is small and the overall slew times the current in the Shutdown pin. The voltage across rate is that of the output stage. The input stage slew rate the resistor in this condition is V+ – 3VBE. For example, is related to the quiescent current and will be reduced as a 82kΩ resistor will set the quiescent supply current to the supply current is reduced. The output slew rate is set 9mA with VS = ±15V. by the value of the feedback resistors and the internal The photos in Figure 4 show the effect of reducing the qui- capacitance. Larger feedback resistors will reduce the escent supply current on the large-signal response. The slew rate as will lower supply voltages, similar to the way Rev C 10 For more information www.analog.com Document Outline Features Applications Typical Application Description Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Small-Signal Bandwidth Typical Performance Characteristics Applications Information Typical Applications Simplified Schematic Package Description Revision History Typical Application Related Parts
APPLICATIONS INFORMATION
15V quiescent current can be reduced to 9mA in the inverting configuration without much change in response. In non- VIN + inverting mode, however, the slew rate is reduced as the LT1210 VOUT quiescent current is reduced. –SD RF –15V 5V 74C906 24kΩ RG ENABLE 15V 1210 F02
Figure 2. Shutdown Interface
resistor speeds up the turn-off time and ensures that the LT1210 is completely turned off. Because the pin is referenced to the positive supply, the logic used should R 1210 F04a F = 750Ω IQ = 9mA, 18mA, 36mA have a breakdown voltage of greater than the positive RL = 10Ω VS = ±15V supply voltage. No other circuitry is necessary as the
(a) AV = –1
internal circuit limits the Shutdown pin current to about 500µA. Figure 3 shows the resulting waveforms. VOUT ENABLE R 1210 F04b F = 750Ω IQ = 9mA, 18mA, 36mA RL = 10Ω VS = ±15V
(b) AV = 2
A 1210 F03 V = 1 RPULL-UP = 24k
Figure 4. Large-Signal Response vs I
R
Q
F = 825Ω VIN = 1VP-P RL = 50Ω VS = ±15V
Slew Rate Figure 3. Shutdown Operation
Unlike a traditional op amp, the slew rate of a current feedback amplifier is not independent of the amplifier gain For applications where the full bandwidth of the amplifier configuration. There are slew rate limitations in both the is not required, the quiescent current of the device may be input stage and the output stage. In the inverting mode, reduced by connecting a resistor from the Shutdown pin and for higher gains in the noninverting mode, the signal to ground. The quiescent current will be approximately 65 amplitude on the input pins is small and the overall slew times the current in the Shutdown pin. The voltage across rate is that of the output stage. The input stage slew rate the resistor in this condition is V+ – 3VBE. For example, is related to the quiescent current and will be reduced as a 82kΩ resistor will set the quiescent supply current to the supply current is reduced. The output slew rate is set 9mA with VS = ±15V. by the value of the feedback resistors and the internal The photos in Figure 4 show the effect of reducing the qui- capacitance. Larger feedback resistors will reduce the escent supply current on the large-signal response. The slew rate as will lower supply voltages, similar to the way Rev C 10 For more information www.analog.com Document Outline Features Applications Typical Application Description Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Small-Signal Bandwidth Typical Performance Characteristics Applications Information Typical Applications Simplified Schematic Package Description Revision History Typical Application Related Parts
