Metrologic Instruments IS4823 - Manual (Page 27)

23
Detailed Electrical Specifications
Absolute Maximum Ratings
Signal Signal Description Minimum Maximum
Vinput † Voltage Applied to Any input pin (except D+ and D-) * -0.3V Vin
Voutput Voltage Applied to Any output pin ** -0.3V Vin + 0.3V
* For USB version, Voltages on D+ and D- signal must conform to USB Specification
** Voutput must be less than 5.5V for all pins
† If the Vinput signal is greater than VIN, current will flow from the input to the VIN pin through the
pull up resistors on the engine. In Suspend Mode, this may cause current to flow into the USB power.
This is not recommended.
IS4823 DC Operating Voltages
Signal Signal Description Minimum Maximum Condition
VIN Operating Voltage 3.0V 3.6V
VIH(1) Input High (RX, CTS) 2.5V
VIL(1) Input Low (RX, CTS) 0.8V
VIH(2) Input High (TTL_INV, nWake) 0.8 x Vin
VIL(2) Input Low (TTL_INV, nWake) 0.8V
VIH(3) Input High (EXT. Trigger) 0.8 x Vin
VIL(3) Input Low (EXT. Trigger) 0.8V
VOH(1) Output High Voltage (TX,RTS) 0.8 x Vin Isource = 16 mA
VOL(1) Output Low Voltage (TX,RTS) 0.14 x Vin Isink = 16 mA
VOH(2) Output High Voltage (nBeeper, nGoodRead) *** 3.6V
VOL(2) Output Low Voltage (nBeeper, nGoodRead) 1.6V Isink = 25 mA
VOH(3) Output High Voltage (Power down) *** 3.6V
VOL(3) Output Low Voltage (Power down) 0.2V Isink = 8 mA
*** PWRDWN, nGoodRead, and nBeeper are open drain outputs w/ 100K pull-ups to VIN. Actual VOH will be determined
by the parallel resistance of the 100K pull up and any external impedance.