A6277SLW Allegro Microsystems Inc, A6277SLW Datasheet - Page 10

• Manufacturer Part Number: A6277SLW
• Description: IC LED DRIVER LINEAR 20-SOIC
• Manufacturer: Allegro Microsystems Inc
• Type: Linear (Non-Switching)r

Specifications of A6277SLW

• Constant Current: Yes
• Topology: 8-Bit Shift Register
• Number Of Outputs: 8
• Internal Driver: Yes
• Type - Primary: General Purpose
• Frequency: 20MHz
• Voltage - Supply: 4.5 V ~ 5.5 V
• Voltage - Output: 1V
• Mounting Type: Surface Mount
• Package / Case: 20-SOIC (7.5mm Width)
• Operating Temperature: -20°C ~ 85°C
• Current - Output / Channel: 120mA
• Internal Switch(s): Yes
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Efficiency: -

A6277
The load current per bit (I
(R
Package Power Dissipation (P
able package power dissipation is determined as
The actual package power dissipation is
When the load supply voltage is greater than 3 V to 5 V,
considering the package power dissipating limits of these
devices, or if P
reducer (V
Load Supply Voltage (V
signed to operate with driver voltage drops (V
to 0.7 V with LED forward voltages (V
4.0 V. If higher voltages are dropped across the driver,
package power dissipation will be increased significantly.
To minimize package power dissipation, it is recom-
mended to use the lowest possible load supply voltage or
to set any series dropping voltage (V
with V
diode (V
EXT
140
120
100
80
60
40
20
0
100
) as shown in the figure below.
DROP
Z
P
CURRENT-CONTROL RESISTANCE, R
), or a series string of diodes (approximately
D
DROP
(act) = dc(V
= I
200
D
o
) should be used.
P
(act) > P
• R
V
D
(max) = (150 - T
DROP
300
DROP
= V
CE
for a single driver, or a Zener
D
LED
O
500
(max), an external voltage
• I
) is set by the external resistor
LED
O
). These devices are de-
700
• 8) + (V
D
- V
8-Bit Serial Input Constant-Current Latched LED Driver
). The maximum allow-
F
A
1 k
)/R
- V
DROP
F
CE
DD
) of 1.2 V to
V
JA
CE
) as
EXT
.
= 0.7 V
• I
2 k
Applications Information
IN OHMS
DD
CE
).
) of 0.4 V
3 k
Dwg. GP-061-1
5 k
0.7 V per diode) for a group of drivers. If the available
voltage source will cause unacceptable dissipation and
series resistors or diode(s) are undesirable, a regulator
such as the Sanken Series SAI or Series SI can be used to
provide supply voltages as low as 3.3 V.
For reference, typical LED forward voltages are:
Pattern Layout. This device has separate logic-ground
and power-ground terminals. If ground pattern layout
contains large common-mode resistance, and the voltage
between the system ground and the LATCH ENABLE or
CLOCK terminals exceeds 2.5 V (because of switching
noise), these devices may not operate correctly.
V
V CE
V DROP
V F
LED
White
Blue
Green
Yellow
Amber
Red
Infrared
115 Northeast Cutoff
1.508.853.5000; www.allegromicro.com
Allegro MicroSystems, Inc.
Worcester, Massachusetts 01615-0036 U.S.A.
1.9 – 2.65 V
1.6 – 2.25 V
1.2 – 1.5 V
3.5 – 4.0 V
3.0 – 4.0 V
1.8 – 2.2 V
2.0 – 2.1 V
Dwg. EP-064
9