Datasheet LT6604-2.5 (Analog Devices) - 9
| Hersteller | Analog Devices |
| Beschreibung | Dual Very Low Noise, Differential Amplifier and 2.5MHz Lowpass Filter |
| Seiten / Seite | 16 / 9 — APPLICATIONS INFORMATION. Interfacing to the LT6604-2.5. Figure 1. Figure … |
| Dateiformat / Größe | PDF / 206 Kb |
| Dokumentensprache | Englisch |
APPLICATIONS INFORMATION. Interfacing to the LT6604-2.5. Figure 1. Figure 2. Figure 3
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LT6604-2.5
APPLICATIONS INFORMATION Interfacing to the LT6604-2.5
operating with a single 3.3V supply and unity passband gain; the input signal is DC-coupled. The common mode Note: The LT6604-2.5 contains two identical lowpass input voltage is 0.5V, and the differential input voltage is fi lters. The following applications information only refers 2V to one fi lter. The two fi lters are independent except that P-P. The common mode output voltage is 1.65V, and the differential output voltage is 2V they share the same negative supply voltage V–. The two P-P for frequencies below 2.5MHz. The common mode output voltage is determined fi lters can be used simultaneously by replicating the ex- by the voltage at V ample circuits. The referenced pin numbers correspond OCM. Since VOCM is shorted to VMID, the output common mode is the mid-supply voltage. In to the A channel fi lter. addition, the common mode input voltage can be equal Each LT6604-2.5 channel requires two equal external re- to the mid-supply voltage of VMID. sistors, RIN, to set the differential gain to 1580Ω/RIN. The Figure 2 shows how to AC couple signals into the LT6604- inputs to the fi lter are the voltages V + – IN and VIN presented 2.5. In this instance, the input is a single-ended signal. to these external components, Figure 1. The difference AC-coupling allows the processing of single-ended or between V + – IN and VIN is the differential input voltage. The differential signals with arbitrary common mode levels. average of V + – IN and VIN is the common mode input voltage. The 0.1μF coupling capacitor and the 1580Ω gain setting Similarly, the voltages V + – OUT and VOUT appearing at pins resistor form a high pass fi lter, attenuating signals below 27 and 29 of the LT6604-2.5 are the fi lter outputs. The dif- 1kHz. Larger values of coupling capacitors will proportion- ference between V + – OUT and VOUT is the differential output ally reduce this highpass 3dB frequency. voltage. The average of V + – OUT and VOUT is the common mode output voltage. Figure 1 illustrates the LT6604-2.5 In Figure 3 the LT6604-2.5 channel is providing 12dB of gain. The common mode output voltage is set to 2V. 3.3V 0.1μF V V 25 3 1580Ω – 3 4 VIN – 27 34 + V + + 1/2 OUT V 2 2 OUT LT6604-2.5 6 V + – IN 0.01μF – V 1 OUT + 2 – VOUT 1 V 29 IN + 1580Ω 0 t 7 0 t – 660425 F01 VIN
Figure 1
3.3V 0.1μF V V 0.1μF 25 1580Ω 2 4 – 3 34 1/2 + 27 V + OUT V + OUT 1 LT6604-2.5 2 6 V + 0.1μF IN 0.01μF – – VOUT 0 t + 2 – VOUT 1 V 29 IN + 1580Ω 7 –1 0 t 660425 F02
Figure 2
5V 0.1μF V V 25 402Ω – 4 3 3 VIN – + + 34 1/2 + 27 VOUT VOUT 2 LT6604-2.5 2 6 0.01μF – – VOUT 500mVP-P (DIFF) + 2 – VOUT 1 1 V 29 IN + V + 402Ω IN 7 0 t – + 0 t V 660425 F03 IN – 2V
Figure 3
660425fa 9
APPLICATIONS INFORMATION Interfacing to the LT6604-2.5
operating with a single 3.3V supply and unity passband gain; the input signal is DC-coupled. The common mode Note: The LT6604-2.5 contains two identical lowpass input voltage is 0.5V, and the differential input voltage is fi lters. The following applications information only refers 2V to one fi lter. The two fi lters are independent except that P-P. The common mode output voltage is 1.65V, and the differential output voltage is 2V they share the same negative supply voltage V–. The two P-P for frequencies below 2.5MHz. The common mode output voltage is determined fi lters can be used simultaneously by replicating the ex- by the voltage at V ample circuits. The referenced pin numbers correspond OCM. Since VOCM is shorted to VMID, the output common mode is the mid-supply voltage. In to the A channel fi lter. addition, the common mode input voltage can be equal Each LT6604-2.5 channel requires two equal external re- to the mid-supply voltage of VMID. sistors, RIN, to set the differential gain to 1580Ω/RIN. The Figure 2 shows how to AC couple signals into the LT6604- inputs to the fi lter are the voltages V + – IN and VIN presented 2.5. In this instance, the input is a single-ended signal. to these external components, Figure 1. The difference AC-coupling allows the processing of single-ended or between V + – IN and VIN is the differential input voltage. The differential signals with arbitrary common mode levels. average of V + – IN and VIN is the common mode input voltage. The 0.1μF coupling capacitor and the 1580Ω gain setting Similarly, the voltages V + – OUT and VOUT appearing at pins resistor form a high pass fi lter, attenuating signals below 27 and 29 of the LT6604-2.5 are the fi lter outputs. The dif- 1kHz. Larger values of coupling capacitors will proportion- ference between V + – OUT and VOUT is the differential output ally reduce this highpass 3dB frequency. voltage. The average of V + – OUT and VOUT is the common mode output voltage. Figure 1 illustrates the LT6604-2.5 In Figure 3 the LT6604-2.5 channel is providing 12dB of gain. The common mode output voltage is set to 2V. 3.3V 0.1μF V V 25 3 1580Ω – 3 4 VIN – 27 34 + V + + 1/2 OUT V 2 2 OUT LT6604-2.5 6 V + – IN 0.01μF – V 1 OUT + 2 – VOUT 1 V 29 IN + 1580Ω 0 t 7 0 t – 660425 F01 VIN
Figure 1
3.3V 0.1μF V V 0.1μF 25 1580Ω 2 4 – 3 34 1/2 + 27 V + OUT V + OUT 1 LT6604-2.5 2 6 V + 0.1μF IN 0.01μF – – VOUT 0 t + 2 – VOUT 1 V 29 IN + 1580Ω 7 –1 0 t 660425 F02
Figure 2
5V 0.1μF V V 25 402Ω – 4 3 3 VIN – + + 34 1/2 + 27 VOUT VOUT 2 LT6604-2.5 2 6 0.01μF – – VOUT 500mVP-P (DIFF) + 2 – VOUT 1 1 V 29 IN + V + 402Ω IN 7 0 t – + 0 t V 660425 F03 IN – 2V
Figure 3
660425fa 9