Measurement Computing USB-1608HS - Manual (Page 26)

USB-1608HS User's Guide Specifications
26
External clock input/output
Table 8. External clock I/O specifications
Parameter Conditions Specification
Pin names SYNC_IN, SYNC_OUT
Pin type SYNC_IN: Input
SYNC_OUT: Output
Pin descriptions SYNC_OUT Outputs A/D pacer clock.
SYNC_IN Receives A/D pacer clock from external source.
Rising edge sensitive.
Input clock rate 250 kHz maximum.
Clock pulse width SYNC_IN 1 µs minimum
SYNC_OUT 2 µs minimum
Input leakage current ±2.0 µA
Input high voltage 3.5 V minimum, 6.5 V absolute maximum
Input low voltage 1.5 V maximum, –0.5 V absolute minimum
Output high voltage (see Note 3) IOH = –2.5 mA 3.3 V minimum
No load 3.8 V minimum
Output low voltage (see Note 3) IOL = 2.5 mA 1.1 V maximum
No load 0.6 V maximum
Note 3: SYNC_OUT is over-current protected with a 200 Ω series resistor.
Counter
Table 9. Counter specifications
Pin name (see Note 4) CTR
Counter type Event counter
Number of channels 1
Input type TTL, rising edge triggered
Input source CTR screw terminal
Resolution 32 bits
Schmidt trigger hysteresis 0.58 V to 0.93 V
Input leakage current ±5 µA
Maximum input frequency 1 MHz
High pulse width 500 ns minimum
Low pulse width 500 ns minimum
Input high voltage 2.4 V minimum, 6.5 V absolute maximum
Input low voltage 2.19 V maximum, –0.5 V absolute minimum
Note 4: CTR is a Schmitt trigger input protected with a 1 kΩ series resistor.
Memory
Table 10. Memory specifications
Data FIFO 65536 samples, 131,072 bytes
EEPROM 512 bytes