AS1109-BSSU austriamicrosystems, AS1109-BSSU Datasheet - Page 8

• Manufacturer Part Number: AS1109-BSSU
• Description: IC LED 4-BIT CC DRIVER 16-SSOP
• Manufacturer: austriamicrosystems
• Type: General Purposer

Specifications of AS1109-BSSU

• Constant Current: *
• Constant Voltage: *
• Topology: *
• Number Of Outputs: *
• Internal Driver: *
• Type - Primary: *
• Type - Secondary: *
• Frequency: *
• Voltage - Supply: *
• Voltage - Output: *
• Mounting Type: Surface Mount
• Package / Case: 16-SSOP
• Operating Temperature: *
• Current - Output / Channel: *
• Internal Switch(s): Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Efficiency: -

AS1109
Datasheet - D e t a i l e d D e s c r i p t i o n
8 Detailed Description
The AS1109 is designed to drive up to 8 LEDs through a fast serial interface and 8 constant-current output drivers. Furthermore, the AS1109 pro-
vides diagnostics for detecting open- or shorted-LEDs, as well as over-temperature conditions for LED display systems, especially LED traffic
sign applications.
The AS1109 contains an 8-bit shift register and an 8-bit data register, which convert serial input data into parallel output format. At AS1109 output
stages, eight regulated current sinks are designed to provide uniform and constant current with excellent matching between ports for driving
LEDs within a wide range of forward voltage variations. External output current is adjustable from 0.5 to 100mA using an external resistor for
flexibility in controlling the brightness intensity of LEDs. The AS1109 guarantees to endure 15V maximum at the outputs.
The serial interface is capable of operating at a minimum of 30 MHz, satisfying the requirements of high-volume data transmission.
Using a multiplexed input/output technique, the AS1109 adds additional functionality to pins SDO, LD and OEN. These pins provide highly useful
functions (open- and shorted-LED detection, over-temperature detection), thus reducing pin count. Over-temperature detection will work on-the-
run, whereas the open- and shorted-LED detection can be used on-the-run or in low-current diagnostic mode
Figure 9. AS1109 - Block Diagram
Serial Interface
Data accesses are made serially via pins SDI and SDO. At each CLK rising edge, the signal present at pin SDI is shifted into the first bit of the
internal shift register and the other bits are shifted ahead of the first bit. The MSB is the first bit to be clocked in. In error-detection mode the shift
register will latch-in the corresponding error data of temperature-, open-, and short-error register with each falling edge of LD.
www.austriamicrosystems.com/LED-Driver-ICs/AS1109
REXT
OEN
CLK
+V
SDI
LD
LED
Indicates 8 Bit Path
OUTN0
OUTN1
Generators
8-Bit Data
8-Bit Shift
Register
Register
Current
OUTN2
Detection
Detailed
Error
Temperature
Detection
OUTN3
Revision 1.20
Error Register
OUTN4
Detection &
8-Bit Open
Control Logic
OUTN5
Error Register
Detection &
8-Bit Short
OUTN6
(see page
AS1109
OUTN7
15).
Detection
Global
Error
SDO
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