XJ128 and XJ128 Plus Printhead
XJ128 Guide to Operation
Xaar Document no: D031010302 Version A
Page 27
6 Electrical Specifications and Data
6.1 Electrical requirements
The printhead utilises two custom IC
’
s in a serial arrangement. Data is transferred via a one
-bit
synchronous serial interface. The operating frequency of the sample clock should be fixed at 1MHz.
Please refer to section 6.1.3 for details. The printhead requires three different power supplies,
providing two discrete voltages; VDD, VPPH and VPPL.
6.1.1 Absolute maximum electrical ratings
If the absolute maximum rating of any of the parameters stated in table 6.1 is exceeded,
the printhead may be permanently damaged. Ensure to use the printhead within the
range of the absolute maximum ratings.
Parameter
Symbol
Rating
Unit
Logic supply voltage
VDD1
-0.5 to +6.0
V
High current high voltage supply
VPPH
-0.5 to +35.0
V
Low current high voltage supply
VPPL
-0.5 to +35.0
V
Logic input voltage
VI
-0.5 to VDD+0.5
V
Logic output voltage
VO
-0.5 to VDD+0.5
V
High current supply feed
IPPH
0-200 per 64 channels
mA
Low current supply feed
IPPL
5
mA
Current per pin
I
100
mA
Table 6.1
–
Absolute maximum electrical ratings
The maximum capacitance for the input and output pins through the XJ128 printhead connector are
shown in table 6.2.
Symbol
Max
Unit
Cin
30
pF
Cout
30
pF
Table 6.2 - Connector pin capacitance
6.1.2 Power supply sequencing
It is important that the power sequencing of the power supplies is maintained at all
times. Failure to do so can result in damage to the IC
’
s within the printhead. This
procedure is crucial and must not be initiated when connecting or disconnecting from
the printhead.
Allow sufficient time for the decoupling capacitors inside the printhead to become charged or
discharged during the power up or power down sequence. Due to the design of the power supply no