LT6604-10 PIN FUNCTIONS+INA and –INA (Pins 2, 4): Channel A Input Pins. Signals V+A and V+B (Pins 25, 17): Positive Power Supply Pins for can be applied to either or both input pins through identi- Channels A and B. For a single 3.3V or 5V supply (Pins 7, cal external resistors, RIN. The DC gain from differential 24, 31, 32 and 35 grounded) a quality 0.1μF ceramic inputs to the differential outputs is 402Ω/RIN. bypass capacitor is required from the positive supply pin (Pins 25, 17) to the negative supply pin (Pins 7, 24, 31, VOCMA (Pin 6): DC Common Mode Reference Voltage 32 and 35). The bypass should be as close as possible to for the 2nd Filter Stage in Channel A. Its value programs the IC. For dual supply applications, bypass the negative the common mode voltage of the differential output of supply pins to ground and Pins 25 and 17 to ground with the fi lter. Pin 6 is a high impedance input, which can be a quality 0.1μF ceramic capacitor. driven from an external voltage reference, or Pin 6 can be tied to Pin 34 on the PC board. Pin 6 should be bypassed +OUTB and –OUTB (Pins 19, 21): Output Pins. Pins 19 and with a 0.01μF ceramic capacitor unless it is connected to 21 are the fi lter differential outputs for channel B. With a a ground plane. typical short-circuit current limit greater than ±40mA, each pin can drive a 100Ω and/or 50pF load to AC ground. V– (Pins 7, 24, 31, 32, 35): Negative Power Supply Pin (can be ground). +OUTA and –OUTA (Pins 27, 29): Output Pins. Pins 27 and 29 are the fi lter differential outputs for channel A. With a VMIDB (Pin 8): The VMIDB pin is internally biased at midsup- typical short-circuit current limit greater than ±40mA, each ply, see the Block Diagram. For single supply operation pin can drive a 100Ω and/or 50pF load to AC ground. the VMIDB pin should be bypassed with a quality 0.01μF ceramic capacitor to ground. For dual supply operation, VMIDA (Pin 34): The VMIDA pin is internally biased at mid- Pin 8 can be bypassed or connected to a high quality DC supply, see the Block Diagram. For single supply operation ground. A ground plane should be used. A poor ground the VMIDA pin should be bypassed with a quality 0.01μF will increase noise and distortion. Pin 8 sets the output ceramic capacitor to ground. For dual supply operation, common mode voltage of the 1st fi lter stage in channel B. Pin 34 can be bypassed or connected to a high quality DC It has a 5.5kΩ impedance, and it can be overridden with ground. A ground plane should be used. A poor ground an external low impedance voltage source. will increase noise and distortion. Pin 34 sets the output common mode voltage of the 1st fi lter stage in channel A. +INB and –INB (Pins 10, 12): Channel B Input Pins. Signals It has a 5.5kΩ impedance, and it can be overridden with can be applied to either or both input pins through identi- an external low impedance voltage source. cal external resistors, RIN. The DC gain from differential inputs to the differential outputs is 402Ω/RIN. Exposed Pad (Pin 35): V–. The exposed pad must be soldered to the PCB. VOCMB (Pin 14): DC Common Mode Reference Voltage for the 2nd Filter Stage in Channel B. Its value programs the common mode voltage of the differential output of the fi lter. Pin 14 is a high impedance input, which can be driven from an external voltage reference, or Pin 14 can be tied to Pin 8 on the PC board. Pin 14 should be bypassed with a 0.01μF ceramic capacitor unless it is connected to a ground plane. 660410fb 7