ZHCSSK2D October 2006 – October 2024 XTR111
PRODUCTION DATA
The XTR111 has additional internal circuitry that detects an error in the output current. In case the controlled output current cannot flow as a result of a wire break, high load resistance, or the output voltage level approaching the positive supply, error flag EF (an open drain logic output), pulls low. When used, this digital output requires an external pullup resistor to logic high (the internal pullup resistor current is 2μA).
The output disable (OD) pin is a logic input with approximately 4μA of current through the internal pullup resistor to 5V. The XTR111 powers up with the output disabled until the OD pin is pulled low. A logic high disables the output to zero output current. This method can be used for calibration, power-on and power-off glitch reduction, and for output multiplexing with other outputs connected to the same pin.
Powering on while the output is disabled (OD = high) cannot fully suppress output glitching. While the supply voltage passes through the range of 3V to 4V, internal circuits turn on. Additional capacitance between the VG and IS pins can suppress the glitch. The smallest glitch energy appears with the OD pin left open; for practical use, however, this pin can be driven high through a 10kΩ resistor before the 24V supply is applied, if logic voltage is available earlier. Alternatively, an open-drain driver can control this pin using the internal pullup current. Pulling up to the internal regulator tends to increase the energy because of the delay of the regulator-voltage increase, again depending on the supply voltage rise time for the first few volts.