HCPL788J Datasheet, PDF (8/20 Pages) Agilent(Hewlett-Packard) – Isolation Amplifier with Short Circuit and Overload Detection

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Notes:
01. In accordance with UL1577, each optocoupler is proof tested by applying an insulation test voltage ≥ 4200 Vrms for 1 second
(leakage detection current limit, I_I-O ≤ 5 µA). This test is performed before the 100% production test for partial discharge
(method b) shown in VDE 0884 Insulation Characteristic Table, if applicable.
02. The Input-Output Momentary Withstand Voltage is a dielectric voltage rating that should not be interpreted as an input-output
continuous voltage rating. For the continuous voltage rating refer to your equipment level safety specification or VDE0884
insulation characteristics table.
03. Device considered a two terminal device: pins 1-8 shorted together and pins 9-16 shorted together.
04. V_DD1 must be applied to both pins 5 and 7. V_DD2 must be applied to both pins 10 and 15.
05. If V_REF exceeds V_DD2 (due to power-up sequence, for example), the current into pin 11 (I_REF) should be limited to 20 mA or less.
06. Input Offset voltage is defined as the DC Input voltage required to obtain an output voltage (at pin 12) of V_REF/2.
07. This is the Absolute Value of Input Offset Change vs. Temperature.
08. This is the Absolute Value of V_OUT Gain Change vs. Temperature.
09. |V_IN+| must exceed this amount in order for the FAULT output to be activated.
10. ABSVAL is derived from V_OUT (which has the gain and offset tolerances stated earlier). ABSVAL is 0 V when V_IN = 0 V and increases
toward V_REF as V_IN approaches +256 mV or -256 mV. ε_ABS is the difference between the actual ABSVAL output and what ABSVAL
should be, given the value of V_OUT. ε_ABS is expressed in terms of
percent of full scale and is defined as ^{|ABSVAL - 2 x | VOUT - VREF / 2| |} x 100.
V_REF
11. CMRR_IN is defined as the ratio of the gain for differential inputs applied between pins 1 and 2 to the gain for common mode inputs
applied to both pins 1 and 2 with respect to pin 8.
12. The signal-to-noise ratio of the HCPL-788J can be improved with the addition of an external low pass filter to the output. See
Frequently Asked Question #4.2 in the Applications Information Section at the end of this data sheet.
13. As measured from 50% of V_IN to 50% of V_OUT.
14. This is the amount of time from when the FAULT Detection Threshold (230 mV ≤ V_THF ≤ 280 mV) is exceeded to when the
FAULT output goes low.
15. This is the amount of time for the FAULT Output to return to a high state once the FAULT Detection Threshold (230 mV ≤ V _THF
≤ 280 mV) is no longer exceeded.
16. Input pulses shorter than the fault rejection pulse width (t_REJECT), will not activate the FAULT (pin 14) output. See Frequently
Asked Question #2.3 in the Applications Information Section at the end of this data sheet for additional detail on how to avoid false
tripping of the FAULT output due to cable capacitance charging transients.
17. CMTI is also known as Common Mode Rejection or Isolation Mode Rejection. It is tested by applying an exponentially rising/falling
voltage step on pin 8 (GND1) with respect to pin 9 (GND2). The rise time of the test waveform is set to approximately 50 ns. The
amplitude of the step is adjusted until V_OUT (pin 12) exhibits more than 100 mV deviation from the average output voltage for more
than 1µs. The HCPL-788J will continue to function if more than 10 kV/µs common mode slopes are applied, as long as the break-
down voltage limitations are observed. [The HCPL-788J still functions with common mode slopes above 10 kV/µs, but output noise
may increase to as much as 600 mV peak to peak.]
18. CMRR is defined as the ratio of differential signal gain (signal applied differentially between pins 1 and 2) to the common mode gain
(input pins tied to pin 8 and the signal applied between the input and the output of the isolation amplifier) at 60 Hz, expressed in dB.