ISL55112 Datasheet, PDF (10/20 Pages) Intersil Corporation – High-Speed Dual Precision CCD Driver

ISL55112
RG_VP
RG_VN
3.3V
CCD Array
with Dual
Video Outputs
RGOUT
RGOUT
RG_VN
RG_VP
PIN 12 (VSUB)
RGIN 1
H1IN 2
3
4
5
H2IN 6
HLIN 7
19
18 H1OUT
17
HXVP
15
14 H2OUT
13
13
H1OUT 14
15
HXVP
17
H2OUT 18
19
7 RGIN
6 H1IN
5
4
3
2 H2IN
1 HLIN
PIN 12 (VSUB)
HLOUT
HLOUT
3.3V
HL_VP
HL_VN
HL_VN
HL_VP
FIGURE 4. SYMMETRY ACCOMMODATES DUAL DEVICE UTILIZATION WITH A DUAL VIDEO CCD DEVICE
Application Information
The ISL55112 2+2 CCD device provides four drivers for
horizontal inputs of CCD arrays. It comprises two high
capacitance drivers (H1/H2) and two low capacitive
drivers for handling Reset Gate (RG)/Last H (HL) inputs
of a CCD device.
From an applications and physical routing standpoint, the
H1/H2 (high current drivers) have identical circuitry.
Likewise, the HL/RG (low current drivers) circuitry is the
same internally. In dual device applications, the user is
free to swap driver outputs to accommodate layout
requirements.
The ISL55112 H1/H2 have fast rise / fall times into large
capacitive loads. H1/H2 are designed with short
propagation delays and tightly controlled skew, allowing
the device to be used on large, fast CCD arrays, used in
image processing applications
Supply Voltages
The ISL55112 has three types of pins when it comes to
supply voltages: Logic, driver rails and device bias
connections.
VDD and Ground Supply Connections
The ISL55112 has a logic supply (V_DD) that can be set
from 2.7V to 5.5V. Hence the V_DD supply voltage sets
the operating thresholds for the digital inputs
H1_IN, H2_IN, RG_IN, HL_IN, and EN pins are high speed
digital logic connections. Typically they are logic
connections coming from the master CCD timing
generator. PD should have fast transitions, but should not
run at frequencies above 1Hz.
CCD Driver Rails
Each of the four driver outputs has its own set of high
and low rail supply connections. The positive rail
connections for the drivers are RG_VP, HL_VP, H1_VP,
H2_VP. The negative driver rail connections are RG_VN,
HL_VN, H1_VN, H2_VN. (Note H1_VN = H2_VN and
should always be at the same voltage).
Once the user has defined the “Driver” amplitudes
required by the CCD, Device bias connections, V_PLUS and
V_SUB must be connected to the maximum and minimum
voltage required.
Device Bias connections
V_PLUS should be connected to the most positive voltage.
V_SUB should be connected to the most negative voltage.
Accordingly, the V_PLUS/ V_SUB connections can only be
determined once the CCD device driver output amplitude
requirements have been determined.
Dual Video CCD Connection Considerations
Physical placement that keeps series inductance to a
minimum is important. The ISL55112 design
accommodates dual device placement close to a CCD
device.
H1 / H2 and RG / HL drivers are internally identical. The
user can rotate the device for PCB placement close to a
single CCD with dual-video requirements.
Power Supply Sequencing
The ISL55112 substrate is connected to the VSUB Pin.
Positive Protection is connected to the VPLUS pin.
The system supply GND connection will always be
present, and is the reference to all other supply voltages.
Therefore apply V_DD, V_PLUS, V_SUB followed by the VP,
VN busses. Digital inputs should be driven as soon as all
10
FN6649.0
September 23, 2009