Texas Instruments manual 2. Single Supply Operation, THS4503EVM Applications

Single-Ended to Fully Differential Application

Figure 3−2. Single Supply Operation

TP1

Vocm

R4

		C13
		1 mF
J1	C1	R2
Vin−		374 W

R1

56.2W

C2 R3

402 W

R17

0

		392 W
	+VS
	3	U1
1	−	4
2	Vocm
8	+	5

THS4503

6

R5

392 W

R6	0	J2
		Vout+
R7	0	J3
		Vout −

Note:

For this and some of the following circuits, it is necessary to install capacitors into locations designated as resistors, and vice versa. Because the capacitors and resistors come in the same case size, this should be easily accomplished.

The designer should note that the ground connection of the schematic at C2 through R17 is a second input—to avoid confusion about whether a coupling capacitor is actually needed. In fact, there is no difference between single-ended and fully differential inputs to the board, except that the single-ended circuits utilize ground as signal return, while fully differential inputs utilize the other input as signal return. Any fully differential input to the board can be converted to a single-ended input merely by connecting one of the inputs to ground.

This circuit allows the input voltage to swing below the negative power supply rail of the op-amp, as shown in Figure 3−3.

THS4503EVM Applications 3-3