Using a negative power supply can extend the common-mode range 14 V more negative than the supply used. For instance, a –10 V supply allows up to –24-V negative common-mode. Remember to keep the total voltage between the GND pin and V+ pin to less than 18 V. The positive common-mode decreases by the same amount.

The reference input simplifies this type of operation because the output quiescent bias point is always based on the reference connections. Figure 7-7 shows a circuit configuration for common-mode ranges from –24 V to 70 V.

A. Connect the REF pins as desired; however, they cannot exceed 9 V greater than the GND pin voltage.

Figure 7-7 Circuit Configuration for Common-Mode Ranges from –24 V to 70 V