a6280ees-t Allegro MicroSystems, Inc., a6280ees-t Datasheet

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a6280ees-t

Manufacturer Part Number
a6280ees-t
Description
3-channel Constant-current Led Driver With Programmable Pwm Control
Manufacturer
Allegro MicroSystems, Inc.
Datasheet
Features and Benefits
▪ 3 × 10-bit PWM brightness settings
▪ 3 × 7-bit dot correction current settings
▪ 5 to 17 V operation
▪ Wide output current range, 10 to 150 mA per channel
▪ Serial port/PWM clock operates at up to 5 MHz
▪ Data and clock logic architecture allows single
▪ Buffered logic outputs to drive cables
▪ Thermal shutdown and UVLO protection
▪ Power-On Reset
Packages: 16 pin DIP (suffix A), and
16 pin QFN (suffix ES)
A6280-DS, Rev. 5
microcontroller control of large quantities of serially-
connected A6280s at fast data transfer rate
Power Supply Bus
Microprocessor
Output Enable
Latch Enable
Control Board
Clock
Data
Figure 1. Functional drawing of daisy chained display application. Additional pixel boards
with A6280 ICs can be applied.
ES, approximate scale 1:1
Cat5 UTP
Clock In
Data In
OE In
Latch In
V
V
3-Channel Constant-Current LED Driver
IN
REG
V
LED
Pixel Board #1
Out
A6280
R
Application Diagram
Out
Clock Out
Latch Out
Data Out
G
OE Out
R
Out
EXT
B
with Programmable PWM Control
Cat5 UTP
Description
The A6280 is a 3-channel constant current LED driver that
has a wide range of output currents. The A6280 controls LED
brightness with a Pulse Width Modulation (PWM) scheme
that gives the application the capability of displaying a billion
colors in an RGB cluster. The maximum current is set by an
external resistor.
The LED brightness is controlled by performing PWM control
on the outputs. The brightness data of the PWM signal for
each LED is stored in three 10-bit registers. The peak value
for each LED can be adjusted (dot-corrected) to compensate
for mismatch, aging, and temperature effects. All the internal
latched registers are loaded by a 31-bit shift register. One
address bit controls whether dot correction/clock divider ratio
or brightness data is loaded into the registers. The remaining
bits are used for the data. This helps reduce the pin count of
the A6280. To further lower the A6280 pin count, the PWM
clock and the serial bus clock share the same pin and work
concurrently to control LED brightness and to load data.
The A6280 is designed to minimize the number of components
needed to drive LEDs with large pixel spacing. A large number
of A6280s can be daisy chained together and controlled by
just four control signals (clock, serial data, latch, and output
enable). Each of these inputs has buffered outputs to drive
the next chip in the chain. Also, VIN can be tied to the LED
Continued on the next page…
Clock In
Data In
OE In
Latch In
V
V
IN
REG
V
LED
Pixel Board #2
Out
A6280
R
Out
Clock Out
Latch Out
Data Out
G
OE Out
R
Out
EXT
B
Cat5 UTP
Pixel Board #N
A6280

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a6280ees-t Summary of contents

Page 1

Features and Benefits ▪ 3 × 10-bit PWM brightness settings ▪ 3 × 7-bit dot correction current settings ▪ operation ▪ Wide output current range 150 mA per channel ▪ Serial port/PWM clock operates ...

Page 2

... Architectural lighting ▪ High intensity monochrome displays ▪ Large video and graphic displays Selection Guide Part Number Packing* A6280EA-T 25 pieces/tube A6280EESTR-T 1500 pieces/reel *Contact Allegro for additional packing options. Absolute Maximum Ratings Characteristic Load Supply Voltage Output Voltage Output Current ...

Page 3

... Exposed thermal pad, not internally connected; connect externally to LGND and PGND. Programmable PWM Control SDO CO 100 ns One-Shot LO OEO Current Regulator 2 OUT2 PGND LGND REXT 1 12 OUT0 VREG 2 11 OUT1 PAD LGND 3 10 PGND VIN 4 9 OUT2 Package ES Description Allegro MicroSystems, Inc. 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 3 ...

Page 4

... OUT = 150 mA – 10 OUT = 10 mA – 50 OUT = 150 mA – 100 OUT – 50 – 50 – 50 – 100 – – Allegro MicroSystems, Inc. 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com Max. Units 5 4.5 V 4.0 V 5.4 V 165 3.0 V ±3 %/V 1.0 μ ...

Page 5

... P(OUT) t P(OUT) Outputs Off Outputs (OE) Figure 3. PWM Counter and Output Timing Programmable PWM Control D15 D14 D0 t P(SD O) D30 P(IO P(OUT) Allegro MicroSystems, Inc. 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 5 ...

Page 6

... SDO 100 ns One-Shot LO Current Test Bit 30 Unused Bits “1” 7 Bits 1 Bit 2 Bits PWM Counter 2 Bit 30 10 Bits “0” OEO Current Regulator 2 OUT2 PGND LGND Allegro MicroSystems, Inc. 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 6 ...

Page 7

... Figure 5. Output Current versus External Resistor, R Programmable PWM Control I (max) = 753. OUT EXT EXT (kΩ) EXT Allegro MicroSystems, Inc. 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com . and I is OUT 65 75 EXT 7 ...

Page 8

... JTSD –∆T ( 15°C typical). The JTSD PWM Counter 2 Address “0” Dot Correction ATB ATB Address “1” Register 2 Allegro MicroSystems, Inc. 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com + V × the OUTi a 8 ...

Page 9

... Alternatively, series resistors can be added to dissipate the extra power and keep the output voltage within the recommended range. 3-Channel Constant-Current LED Driver Programmable with above 3 V, the power PWM Control 9 Allegro MicroSystems, Inc. 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com ...

Page 10

... This will ensure that the setup time at the last pixel in the chain is at least 20 ns. CI(1) to CI(n) is the setup time for signals ( PWM Control , at the × LI(1) to LI( Allegro MicroSystems, Inc. 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 10 ...

Page 11

... PWM Control Red V On LEDs OEO A6280 LO SDO 1 μF Maximum of 10 kΩ 250 pixels X5R OEO A6280 LO SDO Maximum of 1 μF 5 kΩ 250 pixels 10 V Allegro MicroSystems, Inc. 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 11 ...

Page 12

... EIA/JEDEC Standard JESD51-5) D Coplanarity includes exposed thermal pad and terminals Programmable PWM Control 0.010 0.430 0.300 0.30 0.50 0. 1.70 3.10 1.70 3.10 C PCB Layout Reference View Allegro MicroSystems, Inc. 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 12 ...

Page 13

... The in for ma tion in clud ed herein is believed rate and reliable. How ev er, Allegro MicroSystems, Inc. assumes no re spon si bil i ty for its use; nor for any in fringe ment of patents or other rights of third parties which may result from its use. ...

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