ISL55112 Datasheet, PDF (12/20 Pages) Intersil Corporation – High-Speed Dual Precision CCD Driver

ISL55112
Dynamic Measurements
The ISL55112 drivers require minimum series inductance
to operate properly. Therefore it is not recommended
that test sockets be used when evaluating driver
performance. Parts should be soldered to an appropriate
layout that addresses both driver load and driver rail
decoupling series inductance.
Input Signals
The ISL55112 has logic signal inputs on H1,H2, RG and
HL drivers. The ISL55112 also has two “mode control”
pins (PD and EN) which enable the user to control power
requirements. Input signals switching thresholds are set
by the V_DD to Gnd voltage.
Power Saving Mode Control
The ISL55112 offers two methods of power reduction.
The Power Down control pin is to be used in conjunction
with Enable pin. (See “Mode control Power-Down
sequence” and “Mode control Power-Up sequence” on
page 12).
Driver Standby (EN)
(EN: Low, PD Low) In this state the gate drive circuit is
active but the front end receivers are shut off. Shorter
term power savings can be realized by using the EN
input.
When EN is disabled (EN: Low, PD: Low), the driver
outputs will stay in their last state prior to setting the EN
signal low. The “tEN off” specification indicates the
response time for the drivers to hold their present logic
state.
When EN is set to the active state (High), the drivers will
respond to driver inputs. Reaction time to the 1st drive
pulse is defined in the electrical table as “tEN ON” on
page 7.
During initial Power-Up, H1 and H2 Outputs will be HIz
until a transition occurs on the H1 and H2 Inputs.
Device Power-Down (PD)
In Power-Down Mode, both input circuitry and gate drive
circuitry is powered down. Power-down should only be
used for static control. Do not exceed 1Hz of operation.
The recommended sequences for Power Mode control
are:
MODE CONTROL POWER-DOWN SEQUENCE
Device active (Enable High, Power Down Low)
• Set Power Down High Set Enable Low.
MODE CONTROL POWER-UP SEQUENCE
Device inactive (Enable Low, Power Down High)
• Set Enable High, Set Power Down Low
Power Dissipation Considerations
Specifying continuous data rates, driver loads and driver
level amplitudes are key in determining power supply
requirements as well as dissipation/cooling necessities.
Driver Output patterns also impact these needs. The
faster the pin activity, the greater the need to supply
current and remove heat.
TABLE 1. ISL55112 DETAILED POWER DISSIPATION FORMULA/EXAMPLE
FORMULA
VARIABLE
EXAMPLE
VALUES
UNIT
VARIABLES
SQUARED CALCULATIONS
NOTES
POWER DISSIPATION FORMULA ISL55112: OPERATION VARIABLES
VDD
3.3
V
VDD²
10.89
H_Diff
8
V
H_Diff²
64
HL_Dif
8
V
HL_Diff²
64
RG_Diff
8
V
RG_Diff²
64
VDD²
Hx_VP - Hx_VN
HL_VP-HL_VN
RG_VP-RG_VN
H1_Freq
40
MHz
Operating Frequency
H2_Freq
40
MHz
Operating Frequency
HL_Freq
40
MHz
Operating Frequency
RG_Freq
40
MHz
Operating Frequency
Driver Loads
H1_C_LOAD
300
pF
High Capacitance Load
H2_C_LOAD
300
pF
High Capacitance Load
HL_C_LOAD
20
pF
Low Capacitance Load
RG_C_LOAD
20
pF
Low Capacitance Load
POWER DISSIPATION FORMULA ISL55112: DEVICE VARIABLES
Default Currents
IDD
1
mA
Stand By VDD Current
12
FN6649.0
September 23, 2009