Intended for use in ink-jet printer applications, the A5817SEP
addressable 28-line decoder/driver combines low-power CMOS inputs
and logic with 28 high-current, high-voltage bipolar outputs. A 4-to-14
line decoder determines the selected output driver (n) in each
14-driver bank. Two independent output enable inputs (active low)
then provide the final decoding to activate 1- or 2-of-28 outputs
(OUTAn and/or OUTBn). Special internal circuitry is programmed at the
time of manufacture to adjust the output pulse timing and thereby the
energy the device delivers to the ink-jet print head.
The CMOS inputs cause minimal loading and are compatible with
standard CMOS, PMOS, and NMOS logic. Use with TTL or DTL
circuits may require appropriate pull-up resistors to ensure an input
logic high. The internal CMOS logic operates from a 5 V supply.
A CHIP ENABLE function is provided to lock out the drivers during
system power up. The 28 bipolar power outputs are open-collector
30 V Darlington drivers capable of sinking 500 mA at ambient
temperatures up to 85°C.
The A5817SEP is furnished in a 44-lead plastic chip carrier
(quad pack) for minimum-area, surface-mount applications.
ABSOLUTE MAXIMUM RATINGS
at T
= 25°C
A
Output Voltage, VCE............................. 30 V
Logic Supply Voltage, V
Input Voltage Range,
V
....................... -0.3 V to VDD + 0.3 V
IN
Output Current, I
........................... 600 mA
C
Package Power Dissipation, P
Operating Temperature Range,
T
................................. -20°C to +85°C
A
Storage Temperature Range,
T
.............................. -55°C to +150°C
S
*Derate at rate of 22 mW/°C above TA = 25°C.
Caution: CMOS devices have input static
protection but are susceptible to damage
when exposed to extremely high static
electrical charges.
This device is intended specifically for, although
certainly not limited to, driving ink-jet print heads. In
this application, a certain minimum energy (a function
of load voltage and output pulse duration) is required
for proper operation, while excessive energy will
degrade the life of the print head. The output pulse
duration (t
t
is adjusted during manufacture to compensate for
PHL
variations in the output saturation voltage (V
For the A5817SEP, the relationship between t
and t
ENABLE
t
OUT
x 330 ns) + 25 ns + 110 ns.
For most applications, this will result in a drivercontribution-to-energy-error of less than ±4%.
A logic low on the CHIP ENABLE input will
prevent the drivers from turning ON, regardless of the
state of other inputs or the logic supply voltage. The
CHIP ENABLE input has a slow response time and
should not be used as a high-speed control line. For
proper operation, all ground terminals should be
connected to a common ground on the printed wiring
board. The IC (Internal Connection) terminals are
used to program the turn-on time of the device and
MUST be left electrically unconnected (floating) for
proper operation.
) is equal to t
OUT
at TA = 25°C is:
= t
ENABLE
([V
CE(SAT)
+ t
ENABLE
(actual) – V
PLH
– t
PHL
CE(SAT)
, where
CE(SAT)
(typical)]
).
OUT
DECODER TRUTH TABLE
IN
D
(MSB)(LSB)N
00000
00011
00102
00113
01004
01015
01106
01117
10008
10019
101010
101111
110012
110113
1110ALL OFF
1111ALL OFF
Depending on the four address inputs, the 4-to-14 line
decoder selects one driver from each of the 14 output A
and B banks of sink drivers according to the Decoder
Truth Table. The state of the selected outputs is determined by the OUTPUT ENABLE inputs as shown in the
Enable Truth Table.
Allegro MicroSystems, Inc. reserves the right to make, from time to
time, such departures from the detail specifications as may be required
to permit improvements in the design of its products.
The information included herein is believed to be accurate and
reliable. However, Allegro MicroSystems, Inc. assumes no responsibility for its use; nor for any infringements of patents or other rights of third
parties which may result from its use.
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