The output of the OPA564-Q1 shuts down when the E/S pin is forced low. For normal operation (output enabled), pull the E/S pin high (at least 2V greater than V–). To enable the OPA564-Q1 permanently, leave the the E/S pin unconnected. The E/S pin has an internal 100kΩ pullup resistor. When the output is shut down, the output impedance of the OPA564-Q1 is typically 6GΩ || 120pF. Figure 7-6 shows the output shutdown output voltage versus output current. Although the output is high-impedance when shut down, there is still a path through the feedback network into the input stage to ground; see Figure 7-7. To prevent damage to the OPA564-Q1, ensure that the voltage across input pins +IN and –IN does not exceed ±0.5V, and that the current flowing through the input pins does not exceed 10mA when operated beyond the supply rails, V– and V+; see also Input Protection.