Isolation rating: | 300V CAT II, 500V CAT I between BNC |
Transient isolation17: | ground and USB ground |
BNC ground to USB ground |
4.4.2 Performance
Measurement modes: | Frequency and Period |
RUN mode: | Continuous readings |
STOP mode: | Readings frozen |
ONCE mode: | Single reading returning to STOP |
Input connector: | BNC |
Input DC resistance: | 1Meg to GND for inputs between |
| and (INPUT SUPPLY + 0.4V). Outside these |
| ranges DC resistance approximately 90KOhms |
Input capacitance: | 20pF typical |
Input 3dB bandwidth: | 100MHz typical |
Input protection: | ±30V max to GND |
Input supply: | 1.50V to 5.00V in 256 steps of 13.7mV to suit |
| external logic environments (see 2.2) |
Main counter: | |
Maximum count rate: | Guaranteed 50MHz, typically 100MHz with |
| input signal suitable to trigger input threshold |
Master clock: | 12.50MHz, initial accuracy ±0.01%, ageing and |
| drift after 1 year ±0.005%, temp coefficient |
| ±0.005% /oC |
Master clock skew: | For 2 or more stacked USBcount50s, typical 2ns |
| between units |
Internal reference clocks: | 100MHz, 10MHz, 1MHz from internal PLL |
| clocked by master clock |
Internal reference periods: | 0.1s, 1s, 10s divided from master clock |
Period edge detection: | |
|
4.4.3 Miscelaneous
USB transfer rate: | USB 1.118 Full Speed 12MBits/sec |
USB device ID: | 10C4 F004 |
17This figure derives from the 300V CAT II isolation rating and defines the peak transient voltage that can be safely tolerated between the BNC ground and the USB ground.
18Works in USB 1.1 or USB 2.0 hosts using the 12MBits/sec full speed mode
Elan Digital Systems Ltd. | 29 | USBcount50 USER’S GUIDE Iss1 |
