Datasheet LT1969 (Analog Devices) - 10
| Manufacturer | Analog Devices |
| Description | Dual 700MHz, 200mA, Adjustable Current Operational Amplifier |
| Pages / Page | 20 / 10 — TYPICAL PERFOR A CE CHARACTERISTICS. Large-Signal Transient, AV = 10,. … |
| File Format / Size | PDF / 297 Kb |
| Document Language | English |
TYPICAL PERFOR A CE CHARACTERISTICS. Large-Signal Transient, AV = 10,. Large-Signal Transient, AV = – 10,. Low Power**
Model Line for this Datasheet
Text Version of Document
LT1969
W U TYPICAL PERFOR A CE CHARACTERISTICS Large-Signal Transient, AV = 10, Large-Signal Transient, AV = – 10, Low Power** Low Power**
1969 G41 1969 G42 *13k RESISTOR FROM CTRL1 TO V– AND A 49.9k RESISTOR FROM CTRL2 TO V– ** 49.9k RESISTOR FROM CTRL2 TO V–, CTR1 FLOATING
U U W U APPLICATIO S I FOR ATIO Input Considerations
a combination of RF-quality supply bypass capacitors (i.e., 470pF and 0.1µF). As the primary applications have The inputs of the LT1969 are an NPN differential pair high drive current, use low ESR supply bypass capacitors protected by back-to-back diodes (see the Simplified (1µF to 10µF). For best distortion performance with high Schematic). There are no series protection resistors drive current a capacitor with the shortest possible trace onboard which would degrade the input voltage noise. If lengths should be placed between Pins 1 and 5. The the inputs can have a voltage difference of more than 0.7V, optimum location for this capacitor is on the back side of the input current should be limited to less than 10mA with the PC board. external resistance (usually the feedback resistor or source resistor). Each input also has two ESD clamp diodes—one The parallel combination of the feedback resistor and gain to each supply. If an input drive exceeds the supply, limit setting resistor on the inverting input can combine with the current with an external resistor to less than 10mA. the input capacitance to form a pole which can cause frequency peaking. In general, use feedback resistors of The LT1969 design is a true operational amplifier with high 1kΩ or less. impedance inputs and low input bias currents. The input offset current is a factor of ten lower than the input bias
Thermal Issues
current. To minimize offsets due to input bias currents, match the equivalent DC resistance seen by both inputs. The LT1969 enhanced θJA MS10 package has the V– pin The low input noise current can significantly reduce total fused to the lead frame. This thermal connection increases noise compared to a current feedback amplifier, especially the efficiency of the PC board as a heat sink. The PCB for higher source resistances. material can be very effective at transmitting heat between the pad area attached to the V– pin and a ground or power
Layout and Passive Components
plane layer. Copper board stiffeners and plated through- holes can also be used to spread the heat generated by the With a gain bandwidth product of 700MHz the LT1969 device. Table 1 lists the thermal resistance for several requires attention to detail in order to extract maximum different board sizes and copper areas. All measurements performance. Use a ground plane, short lead lengths and 10
W U TYPICAL PERFOR A CE CHARACTERISTICS Large-Signal Transient, AV = 10, Large-Signal Transient, AV = – 10, Low Power** Low Power**
1969 G41 1969 G42 *13k RESISTOR FROM CTRL1 TO V– AND A 49.9k RESISTOR FROM CTRL2 TO V– ** 49.9k RESISTOR FROM CTRL2 TO V–, CTR1 FLOATING
U U W U APPLICATIO S I FOR ATIO Input Considerations
a combination of RF-quality supply bypass capacitors (i.e., 470pF and 0.1µF). As the primary applications have The inputs of the LT1969 are an NPN differential pair high drive current, use low ESR supply bypass capacitors protected by back-to-back diodes (see the Simplified (1µF to 10µF). For best distortion performance with high Schematic). There are no series protection resistors drive current a capacitor with the shortest possible trace onboard which would degrade the input voltage noise. If lengths should be placed between Pins 1 and 5. The the inputs can have a voltage difference of more than 0.7V, optimum location for this capacitor is on the back side of the input current should be limited to less than 10mA with the PC board. external resistance (usually the feedback resistor or source resistor). Each input also has two ESD clamp diodes—one The parallel combination of the feedback resistor and gain to each supply. If an input drive exceeds the supply, limit setting resistor on the inverting input can combine with the current with an external resistor to less than 10mA. the input capacitance to form a pole which can cause frequency peaking. In general, use feedback resistors of The LT1969 design is a true operational amplifier with high 1kΩ or less. impedance inputs and low input bias currents. The input offset current is a factor of ten lower than the input bias
Thermal Issues
current. To minimize offsets due to input bias currents, match the equivalent DC resistance seen by both inputs. The LT1969 enhanced θJA MS10 package has the V– pin The low input noise current can significantly reduce total fused to the lead frame. This thermal connection increases noise compared to a current feedback amplifier, especially the efficiency of the PC board as a heat sink. The PCB for higher source resistances. material can be very effective at transmitting heat between the pad area attached to the V– pin and a ground or power
Layout and Passive Components
plane layer. Copper board stiffeners and plated through- holes can also be used to spread the heat generated by the With a gain bandwidth product of 700MHz the LT1969 device. Table 1 lists the thermal resistance for several requires attention to detail in order to extract maximum different board sizes and copper areas. All measurements performance. Use a ground plane, short lead lengths and 10
