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Datasheet: AS1109 8-Bit LED Driver with Diagnostics

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AS1109

Constant-Current, 8-Bit LED Driver with Diagnostics

www.ams.com/LED-Driver-ICs/AS1109 Revision 1.21 1 - 24

1 General Description

The AS1109 is designed to drive up to 8 LEDs through a fast serial

interface and features 8 output constant current drivers and an on-

chip diagnostic read-back function.

The high clock-frequency (up to 50MHz), adjustable output current,

and flexible serial interface makes the device perfectly suited for

high-volume transmission applications.

Output current is adjustable (up to 100mA/channel) using an external

resistor (REXT).

The serial interface with Schmitt trigger inputs includes an integrated

shift register. Additionally, an internal data register stores the

currently displayed data.

The device features integrated diagnostics for over-

temperature, open-LED, and shorted-LED conditions. Integrated

registers store global fault status information during load as well as

the detailed temperature/open-LED/shorted-LED diagnostics results.

The AS1 109 also features a low-current diagnostic mode to minimize

display flicker during fault testing.

With an operating temperature range from -40 to +125°C the

AS1109 is also ideal for industrial applications.

The AS1109 is available in a 16-pin SOIC-150, a 16-pin QFN

(4x4mm) and the 16-pin QSOP-150 package.

Figure 1. Main Diagram and Pin Assignments

2 Key Features

8 Constant-Current Output Channels

Excellent Output Current Accuracy

- Between Channels: ±2%

- Between AS1109 Devices: ±2%

Output Current Per Channel: 0.5 to 100mA

Controlled In-Rush Current

Over-Temperature, Open-LED, Shorted-LED

Diagnostics Functions

Low-Current Test Mode

Global Fault Monitori ng

Low Shutdown Mode Current: 3µA

Fast Serial Interface: up to 50MHz

Cascaded Configuration

Fast Output Drivers Suitab le for PWM

16-pin SOIC-150, 16-pin QFN (4x4mm) and 16-pin QSOP-150

Package

3 Applications

The device is ideal for fixed- or slow-rolling displays using static or

multiplexed LED matrix and dimming functions, large LED matrix

displays, mixed LED display and switch monitoring, displays in

elevators, public transports (underground, trains, buses, taxis,

airplanes, etc.), large displays in stadiums and public areas, price

indicators in retail stores, promotional panels, bar-graph displays,

industrial controller displays, white good panels, emergency light

indicators, and traffic signs.

AS1109

SDI SDO

CLK LD OEN REXT

+VLED

GND

AS1109

16 VDD

SDI

CLK

OUTN0

15 REXT

14 SDO

13 OEN

9OUTN4

OUTN3

OUTN2

OUTN1

12 OUTN7

11 OUTN6

10 OUTN5

OUTN0 OUTN1 OUTN2 OUTN3 OUTN4 OUTN5 OUTN6 OUTN7

GND VDD

www.ams.com/LED-Driver-ICs/AS1109 Revision 1.21 2 - 24

AS1109

Datasheet

4 Pin Assignments

Figure 2. Pin Assignments (Top View)

4.1 Pin Descriptions

Table 1. Pin Descriptions

Pin Number Pin Name Description

16-pin QSOP-150

16-pin SOIC-150 16-pin QFN

(4x4mm)

115GND

Ground

216SDI

Serial Data Input

31CLK

Serial Data Clock. The rising edge of the CLK signal is used to clock data into and at

the falling edge out of the AS1 109 shift register . In error mode, the rising edge of the CLK

signal is used to switch error modes.

42LD

Serial Data Load. Data is transferred to the data register at the rising edge of this pin.

5:12 3:10 OUTN0:7 Output Current Drivers. These pins are used as LED drivers or for input sense for

diagnostic modes.

13 11 OEN

Output Enable. The active-low pin OEN signal can always enable output drivers to sink

current independent of the AS1109 mode.

0 = Output drivers are enabled.

1 = Output drivers are disabled.

14 12 SDO

Serial Data Output. In normal mode SDO is clocked out 8.5 clock cycles after SDI is

clocked in.

In global error detection mode this pin indicates the occurrence of a global error.

0 = Global error mode returned an error.

1 = No errors.

15 13 REXT External Resistor Connection. This pin connects through the external resistor (REXT)

to GND, to setup the load current.

16 14 VDD Positive Supply Voltage

GND

AS1109

16 VDD

SDI

CLK

OUTN0

15 REXT

14 SDO

13 OEN

9OUTN4

OUTN3

OUTN2

OUTN1

12 OUTN7

11 OUTN6

10 OUTN5

SDO

OUTN2

GND VDD REXT

OUTN7

1415

CLK 1

LD 2

OUTN1 4

AS1109

16-pin QFN

(4x4mm)

OUTN0 3

7 8

OUTN6

OEN

SDI

OUTN3

OUTN4

OUTN5

16-pin QSOP-150

16-pin SOIC-150

www.ams.com/LED-Driver-ICs/AS1109 Revision 1.21 3 - 24

AS1109

Datashee t - A b s o l u t e M a x i mu m R a t i n g s

5 Absolute Maximum Ratings

Stresses beyond those listed in Table 2 may cause permanent damage to the device. These are stress ratings only, and functional operation of

the device at these or any other conditions beyond those indicated in Electrical Characteristics on page 4 is not implied. Exposure to absolute

maximum rating conditions for extended periods may affect device reliability.

Table 2. Absolute Maximum Ratings

Parameter Min Max Units Comments

Electrical Parameters

VDD to GND -0.3 7 V

Input Voltage -0.4 VDD + 0.4 V

Output Voltage -0.4 15 V

GND Pin Current 1000 m A

Input Current (latch-up immunity) -100 100 mA Norm: JEDEC 78

Electrostatic Discharge

Electrostatic Discharge HBM 2 kV Norm: MIL 883 E method 3015

Temperature Ranges and Storage Conditions

Thermal Resistance ΘJA

33 ºC/W on PCB, 16-pin SOIC-150 package

113 ºC/W on PCB, 16-pin QSOP-150 package

32 ºC/W on PCB, 16-pin QFN (4x4mm) package

Storage Temperature Range -55 +150 ºC

Package Body Temperature +260 ºC

The reflow peak soldering temperature (body

temperature) specified is in accordance with IPC/

JEDEC J-STD-020“Moisture/Reflow Sensitivity

Classification for Non-Hermetic Solid State Surface

Mount Devices”.

The lead finish for Pb-free leaded packages is matte tin

(100% Sn).

Humidity non-condensing 5 85 %

Moisture Sensit iv e Level QFN and QSOP 1 Represents a maximum floor life time of unlimited

Moisture Sensitive

Layer (SOIC) 3 Represents a maximum floor life of 168h

www.ams.com/LED-Driver-ICs/AS1109 Revision 1.21 4 - 24

AS1109

Datasheet - Electrical Characteristics

6 Electrical Characteristics

VDD = +3.0V to +5.5V, Typical values measured at VDD = 5V, TAMB = 25°C (unless otherwise specified).

Table 3. Electrical Characteristics

Symbol Parameter Condition Min Typ Max Unit

TAMB Operating Temperature Range Device fully functional up to 125°C -40 +85 °C

VDD Supply Voltage 3.0 5.5 V

VDS Output Voltage OUTN0:7 0 15.0 V

IOUT

Output Current

OUTN0:7, VDD = 5V (see Figure 8) 0.5 100

IOH SDO -1.0

IOL SDO 1.0

VIH Input Voltage High Level CLK, OEN, LD, SDI

0.7 x

VDD VDD +

0.3 V

VIL Low Level -0.3 0.3 x

VDD

IDS(OFF) Output Leakage Current OEN = 1, VDS = 15.0V 0.5 µA

VOL Output

Voltage SDO IOL = +1.0mA 0.4 V

VOH IOH = -1.0mA VDD -

0.4V

IAV(LC1) Device-to-Device Average Output Current

from OUTN0 to OUTN7 VDS = 0.5V, VDD = Const.,

REXT = 744Ω24.5 25.26 26 mA

ΔIAV(LC1) Current Skew

(Between Channels) VDS ≥ 0.5V, VDD = Const.,

REXT = 744Ω ±0.9 ±3 %

IAV(LC2) Device-to-Device Average Output Current

from OUTN0 to OUTN7 VDS = 0.6V, VDD > 3.3V,

REXT = 372Ω49.50 50.52 51.55 mA

ΔIAV(LC2) Current Skew

(Between Channels) VDS ≥ 0.6V, VDD = Const.,

REXT = 372Ω ±0.8 ±2 %

IAV(LC3) Device-to-Device Average Output Current

from OUTN0 to OUTN7 VDS = 0.8V, VDD = 5.0V,

REXT = 186Ω 98 101 104 mA

ΔIAV(LC3) Current Skew

(Between Channels) VDS ≥ 0.8V, VDD = Const.,

REXT = 186Ω±0.5 ±2 %

ILC Low-Current Diagnosis Mode VDS = 0.8V, VDD = 5.0V 0.4 0.6 0.8 mA

IPD Power Down Supply Current VDS = 0.8V, VDD = 5.0V,

REXT = 372Ω, OUTN0:7 = On 320µA

%/ΔVDS Output Current vs.

Output Voltage Regulation VDS within 1.0 and 3.0V ±0.1 %/V

%/ΔVDD Output Current vs.

Supply Voltage Regulation VDD within 3.0 and 5.0V ±1 %/V

RIN(UP) Pullup Resistance OEN 250 500 800 kΩ

RIN(DOWN) Pulldown Resistance LD 250 500 800 kΩ

VTHL* Open Error Detection Threshold Voltage No load 0.25 0.35 0.45 V

VTHH* Short Error Detection Threshold Voltage VDD = 3.0V, no load 1.2 1.3 1.4 V

VDD = 5.0V, no load 2.0 2.2 2.4

TOV1 Overtemperature Threshold Flag 150 ºC

www.ams.com/LED-Driver-ICs/AS1109 Revision 1.21 5 - 24

AS1109

Datasheet - Electrical Characteristics

6.1 Switching Characteristics

VDD = 3.0 to 5.5V, VDS = 0.8V, VIH = VDD, VIL = GND, REXT = 372Ω, VLOAD = 4.0V, RLOAD = 64Ω, CLOAD = 10pF; guaranteed by design.

* If multiple AS1109 devices are cascaded and tr or tf is large, it may be critical to achieve the timing required for data transfer between two

cascaded LED drivers.

Note: All limits are guaranteed. The parameters with min and max values are guaranteed with production tests or SQC (Statistical Quality

Control) methods.

IDD(OFF)0

Supply Current

Off

REXT = Open‚ OUTN0:7 = Off 1.3 2

IDD(OFF)1 REXT = 744Ω‚ OUTN0:7 = Off 3.0 3.68

IDD(OFF)2 REXT = 372Ω‚ OUTN0:7 = Off 4.7 5.37

IDD(OFF)3 REXT = 186Ω, OUTN0:7 = Off 8.1 8.73

IDD(ON)1

REXT = 744Ω‚ OUTN0:7 = On 4.5 5

IDD(ON)2 REXT = 372Ω‚ OUTN0:7 = On 7.5 8

IDD(ON)3 REXT = 186Ω‚ OUTN0:7 = On 13.7 15

Table 4. Switching Characteristics

Symbol Parameter Conditions Min Typ Max Unit

tP1 Propagation Delay T i me CLK - SDO 5 10 nstP2 Propagation Delay Time (Without Staggered

Output Delay) LD - OUTNn 100 200

tP3 OEN - OUTNn 100 200

tP4 Propagation Delay Time 10 ns

tW(CLK) Pulse Width CLK 15 nstW(L) LD 15

tW(OE) OEN (@IOUT < 60mA) 200

tR *Maximum CLK Rise Time 500 ns

tF *Maximum CLK Fall Time 500 ns

tOR Output Rise Time of VOUT (Turn Off) 100 200 ns

tOF Output Fall Time of VOUT (Turn On) 100 300 ns

tSU(D) Setup Time for SDI 5 ns

tH(D) Hold Time for SDI 5 ns

tSU(L) Setup Time for LD 5 ns

tH(L) Hold Time for LD 5 ns

tTESTING Minimum OEN Time for Error Detection 2000 ns

tSTAG Staggered Output Delay 20 40 ns

tSU(OE) Output Enable Setup Time 20 ns

tGSW(ERROR) Global Error Switching Setup Time 10 ns

tSU(ERROR) Global Error Detection Setup Time 10 ns

tP(I/O) Propagation Delay Global Error Flag 5 ns

tSW(ERROR) Switching Time Global Error Flag 10 ns

fCLK Maximum Clock Frequency

(Cascade Operation) 30 50 MHz

tP3,ON Low-Current Test Mode

Propagation Delay Time Turn ON 3 5 µs

tTP3,OFF Turn OFF 0.05 0.1 µs

tREXT2,1 External Resistor Reaction Time Change from REXT1 = 372Ω, IOUT1

= 50.52mA to REXT2 = 37.2kΩ,

IOUT2 < 1mA

0.5 1 µs

tREXT2,1 External Resistor Reaction Time Change from REXT1 = 37.2kΩ,

IOUT1 = 0.5mA to REXT2 = 372Ω,

IOUT2 > 25mA

0.5 1 µs

Table 3. Electrical Characteristics (Continued)

Symbol Parameter Condition Min Typ Max Unit

www.ams.com/LED-Driver-ICs/AS1109 Revision 1.21 6 - 24

AS1109

Datasheet - Typical Operating Characteristics

7 Typical Operating Characteristics

Figure 3. Output Current vs. REXT, Figure 4. Relative Output Current Error vs. VDD,

VDD = 5V; VOUT = 0.8V, TAMB = 25°C Iout/Iout@VDD = 5V - 1, TAMB = 25°C

Figure 5. Output Current vs. VDS; Figure 6. Output Current vs. VDS;

VDD = 5V, TAMB = 25°C VDD = 5V, TAMB = 25°C

Figure 7. Relative IOUT Error vs. Temperature Figure 8. Output Current vs. VDD

VDD = 5V, Iout/Iout@25°C - 1, TAMB = 25°C

100

100 1000 10000

REXT (Ohm)

IOUT (mA) .

-2

-1.5

-1

-0.5

0.5

1.5

33.544.555.5

VDD (V)

Relat iv e Out put Cur r ent Er r or (%)

REXT = 744Ω;

VDS = 0.5V

REXT = 372Ω;

VDS = 0.6V

REXT = 186Ω;

VDS = 0.8V

100

120

140

160

02468101214

VDS (V)

IOUT (mA) .

REXT = 127Ω

REXT = 251Ω

REXT = 372Ω

REXT = 150Ω

REXT = 186Ω

REXT = 744Ω

100

120

140

160

0 0.2 0.4 0.6 0.8 1 1.2 1.4

VDS (V)

IOUT (mA) .

REXT = 127Ω

REXT = 251Ω

REXT = 372Ω

REXT = 150Ω

REXT = 186Ω

REXT = 744Ω

-1

-0.5

0.5

-50-250255075100

Temperature ( °C)

Relat iv e Out put Cur r ent Er r or (%)

REXT = 372Ω;

VDS = 0.6V

REXT = 744Ω;

VDS = 0.5V

REXT = 186Ω;

VDS = 0.8V

100

120

140

160

3 3.5 4 4.5 5 5.5

VDD (V)

IOUT (mA) .

VDS = 1V

VDS = 0.9V

VDS = 0.8V

VDS = 0.7V

VDS = 0.6V

VDS = 0.5V

www.ams.com/LED-Driver-ICs/AS1109 Revision 1.21 7 - 24

AS1109

Datasheet - Detailed Description

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

provides diagnostics for detecting open- or shorted-LEDs, as well as over-temperature conditions for LED display systems, especially LED traffic

sign application s.

The AS1 109 contains an 8-bit shift register and an 8-bit data register , which convert serial input data into parallel output format. At AS1 109 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 (see page 14).

Figure 9. AS1109 - Block Diagram

8.1 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.

AS1109

REXT

OEN

CLK

SDI

Current

Generators

Detailed

Error

Detection

8-Bit Data

8-Bit Shift

Temperature

Detection 8-Bit Open Detec-

tion & Error Reg-

ister

8-Bit Short

Detection & Error

Global Error

Detection

SDO

Indicates 8 Bit Path

Control Logic

+VLED

OUTN0 OUTN1 OUTN2 OUTN3 OUTN4 OUTN5 OUTN6 OUTN7

www.ams.com/LED-Driver-ICs/AS1109 Revision 1.21 8 - 24

AS1109

Datasheet - Detailed Description

The 8-bit data register will latch the data of the shift register at each rising edge of LD. This data is then used to drive the current generator output

drivers to switch on the corresponding LEDs as OEN goes low.

8.2 Timing Diagrams

This section contains timing diagrams referenced in other sections of this data sheet.

Figure 10. Normal Mode Timing Diagram

Figure 11. Output Delay Timing Diagram

OEN

OUTNx

SDO

SDI

CLK

tSU(L) tH(L)

tW(L)

tW(CLK)

tP1

tH(D)

50% 50% 50%

50% 50%

50%

tSU(D)

OEN Low = Ou tput Enabl e d

tP2

OUTNx High = Output Off

OUTNx Low = Output On

50%

50% 50%

tW(OE)

7XtSTAG

tP3

OEN

OUTN0

OUTN1

OUTN7

50% 50%

50%50%

tOF tOR

tSTAG

90% 90%

10% 10%

7XtSTAG

tSTAG

tP3

50% 50%

www.ams.com/LED-Driver-ICs/AS1109 Revision 1.21 9 - 24

AS1109

Datasheet - Detailed Description

Figure 12. Data Input Timing Diagram

Figure 13. Data Input Example Timing Diagram

SDI

CLK

OEN

SDO

8 CLK Pulses

tSU(OE)

tW(L)

tSU(L

tW(OE)

tH(D)

tP1

Data Bit

7Data Bit

6Data Bit

5Data Bit

4Data Bit

3Data Bit

2Data Bit

1Data Bit

Old Data

Bit 7 Old Data

Bit 6 Old Data

Bit 5 Old Data

Bit 4 Old Data

Bit 3 Old Data

Bit 2 Old Data

Bit 1 Old Data

Bit 0

Don’t Care

tSU(D)

SDI

OEN

OUTN0

OUTN1

OUTN7

OUTN2

OUTN3

OUTN4

OUTN5

OUTN6

Off

D6D7 D5 D4 D3 D2 D1 D0

1234567

Time = 0

CLK

www.ams.com/LED-Driver-ICs/AS1109 Revision 1.21 10 - 24

AS1109

Datasheet - Detailed Description

Figure 14. Switching Global Error Mode Timing Diagram

8.3 Error-Detection Mode

Acquisition of the error status occurs at the rising edge of OEN. Error-detection mode is started on the rising edge of LD when OEN is high. The

CLK signal must be low when entering error detection mode. Error detection for open- and shorted-LEDs can only be performed for LEDs that

are switched on during test time. To switch between error-detection modes clock pulses are needed (see Table 5).

Note: To test all LEDs, a test pattern that turns on all LEDs must be input to the AS1109.

8.4 Global Error Mode

Global error mode is entered when error-detection mode is started. Clock pulses during this period are used to select between temperature,

open-LED, and shorted-LED tests, as well as low-current diagnostic mode and shutdown mode (see Table 5). In global error mode, an error flag

(TFLAG, OFLAG, SFLAG) is delivered to pin SDO if any errors are encountered.

Note: For a valid result SDI must be 1 for the first device.

If there are multiple AS1 109s in a chain, the error flag will be gated through all devices. To get a valid result at the end of the chain, a logic 1 must

be applied to the SDI input of the first device of the chain. If one device produces an error this error will show up after n*tP(I/O) + tSW(ERROR) at

pin SDO of the last device in the chain. This means it is not possible to identify which device in the chain produced the error. Therefore, if a global

error occurs, the detailed error report can be run to identify which AS1109, or LED produced the error.

Note: When no error has occurred, the detailed error report can be skipped, setting LD and subsequently OEN low.

Table 5. Global Error Mode Selections

Clock

Pulses Output Port Error-Detection Mode Global Error Flag/Shutdown Condition

0 Don't Care Over-Tempe rature Detection TFLAG = SDO = 1: No over-temperature warning.

TFLAG = SDO = 0: Over-temperature warning.

1 Enabled Open-LED Detection OFLAG = SDO = 1: No open-LED error.

OFLAG = SDO = 0: Open-LED error.

2 Enabled Shorted-LED Detection SFLAG = SDO = 1: No shorted-LED error.

SFLAG = SDO = 0: Shorted-LED error.

3 Don't Care Low-Current Diagnostic Mode

4 Don't Care Shutdown Mode SDI = 1: Wakeup

SDI = 0: Shutdown

tTESTING

tSU(ERROR)

OFLAG(IN) SFLAG(IN)TFLAG(IN)

TFLAG OFLAG SFLAG

tSW(ERROR)

SDI

OEN

CLK

SDO

Acquisition of Error

Status

Don’t

Care Don’t

Care

tGSW(ERROR)

tP(I/O)

tP4

tP(I/O) tP(I/O)

tSW(ERROR)

tGSW(ERROR)

Don’t

Care

www.ams.com/LED-Driver-ICs/AS1109 Revision 1.21 11 - 24

AS1109

Datasheet - Detailed Description

8.5 Error Detection Functions

8.5.1 Open-LED Detection

The AS1109 open-LED detection is based on the comparison between VDS and VTHL. The open LED status is aquired at the rising edge of

OEN and stored internally. While detecting open-LEDs the output port must be turned on. Open LED detection can be started with 1 clock pulse

during error detection mode while the output port is turned on.

Note: LEDs which are turned off at test time cannot be tested.

8.5.2 Shorted-LED

The AS1109 shorted-LED detection is based on the comparison between VDS and VTHH. The shortened LED status is acquired at the rising

edge of OEN and stored internally. While detecting shorted-LEDs the output port must be turned on. Shorted-LED detection can be started with

2 clock pulses during error detection mode while the output port is turned on.

For valid results, the voltage at OUTN0:OUTN7 must be lower then VTHH under low-current diagnostic mode operating conditions. This can be

achieved by reducing the VLED voltage or by adding additional diodes, resistors or LED’s.

Note: LEDs which are turned off at test time cannot be tested.

8.5.3 Overtemperature

Thermal protection for the AS1109 is provided by continuously monitoring the device’s core temperature. The overtemperature status is aquired

at the rising edge of OEN and stored internally.

Table 6. Open LED Detection Modes

Output Port State Effective Output

Point Conditions Detected Open-LED

Error Status Code Meaning

On VDS < VTHL 0 Open Circuit

On VDS > VTHL 1 Normal

Table 7. Shorted LED Detection Modes

Output Port State Effective Output

Point Conditions Detected Shorted-LED

Error Status Code Meaning

On VDS > VTHH 0 Short Circuit

On VDS < VTHH 1 Normal

Table 8. Overtemperature Modes

Output Port State Effective Output

Point Conditions Detected Overtemperature

Status Code Meaning

Don’t Care Temperature > TOV1 0 Overtemperature Condition

Don’t Care Temperature < TOV1 1Normal

www.ams.com/LED-Driver-ICs/AS1109 Revision 1.21 12 - 24

AS1109

Datasheet - Detailed Description

8.6 Detailed Error Reports

The detailed error report can be read out after global error mode has been run. On the falling edge of LD, the detailed error report of the selected

test is latched into the shift register and can be clocked out with n*8 clock cycles (n is the number of AS1109s in a chain) via pin SDO. At the

same time new data can be written into the shift register, which will load on the next rising edge of pin LD. This data will show at the output

drivers, at the falling edge of OEN.

8.6.1 Detailed Temperature Warning Report

The detailed temperature warning report can be read out immediately after global error mode has been run. Bit0 of the 8bit data word represents

the temperature flag of the chip.

Figure 15. Detailed Temperature Warning Report Timing Diagram

Detailed Temperature Warning Report Example

Consider a case where five AS1109s are cascaded in one chain. The detailed error report lists the temperatures for each device in the chain:

IC1:[70°] IC2:[85°] IC3:[66°] IC4:[160°] IC5:[76°]

In this case, IC4 is overheated and will generate a global error, and therefore 5*8 clock cycles are needed to write out the detailed temperature

warning report, and optionally read in new data. The detailed temperature warning report would look like this:

XXXXXXX1 XXXXXXX1 XXXXXXX1 XXXXXXX0 XXXXXXX1

The 0 in the detailed temperature warning report indicates that IC4 is the device with the over-temperature condition.

Note: In an actual report there are no spaces in the output.

Global Flag Readout Detailed Error Report Readout

tH(L)

tP4

SDI

OEN

CLK

SDO

New Data Input

TFLAG

DBit7

Undefined

Don’t

Care

Don’t

Care

Temperature Error Report Output

DBit6 DBit5 DBit4 DBit3 DBit2 DBit1 DBit0

TBit0

t(SU)ERROR

tP1

For detailed timing information see Timing Diagrams on page 8.

tGSW(ERROR)

www.ams.com/LED-Driver-ICs/AS1109 Revision 1.21 13 - 24

AS1109

Datasheet - Detailed Description

8.6.2 Detailed Open-LED Error Report

The detailed open-LED error report can be read out immediately after global error mode has been run.

Figure 16. Detailed Open-LED Error Report Timing Diagram

Detailed Open-LED Error Report Example

Consider a case where five AS1109s are cascaded in one chain. A 1 indicates a LED is on, a 0 indicates a LED is off, and an X indicates an open

LED. The open-LED test is only applied to LEDs that are turned on. This test is used with a test pattern where all LEDs are on at test time.

IC1:[11111111] IC2:[111XX111] IC3:[11111111] IC4:[1X111111] IC5:[11111111]

IC2 has two open LEDs and IC4 has one open LED switched on due to input. 5*8 clock cycles are needed to write the entire error code out. The

detailed error report would look like this:

Comparing this report with the input data indicates that IC2 is the device with two open LEDs at position 4 and 5 and IC4 with an open LED at

second position. For such a test it is recommended to enter low-current diagnostic mode first (see Low-Current Diagnostic Mode on page 14) to

reduce onscreen flickering.

Note: In an actual report there are no spaces in the output.

LEDs turned off during test time cannot be tested.

Input Data:11111111 11111111 1 1111111 11111111 11111111

LED Status:11111111 111XX111 11111111 1X111111 11111111

Failure Code:11111111 11100111 11111111 10111111 11111111

Acquisition of

Error Status

Global Flag Readout Detailed Error Report Readout

SDI

OEN

CLK

SDO

tH(L)

Open Error Report Output

New Data Input

tP4

tP1

tP4

tSW(ERROR)

tSU(ERROR)

tTESTING

DBit0DBit1DBit2DBit3DBit4DBit5DBit6

OBit0OBit1OBit2OBit3OBit4OBit5OBit6

Don’t

Care

Don’t

Care

OBit7

TFlag OFlag

DBit7

For detailed timing information see Timing Diagrams on page 8.

tGSW(ERROR)

www.ams.com/LED-Driver-ICs/AS1109 Revision 1.21 14 - 24

AS1109

Datasheet - Detailed Description

8.6.3 Detailed Shorted-LED Error Report

The detailed shorted-LED error report can be read out immediately after global error mode has been run (see Global Error Mode on page 10).

Figure 17. Deta iled Shorted-LED Error Report Timing Diagram

Detailed Shorted-LED Error Report Example

Consider a case where five AS1109s are cascaded in one chain. A 1 indicates a LED is on, a 0 indicates a LED is off, and an X indicates a

shorted LED. This test is used with a test pattern where all LEDs are on at test time. Additionally, this test should be run after starting low-current

diagnostic mode (see Low-Current Diagnostic Mode on page 14).

IC1:[11111XX1] IC2:[11111111] IC3:[11111111] IC4:[111X1111] IC5:[11111111]

IC2 has two shorted LEDs and IC4 has one shorted LED switched on due to input. 5*8 clock cycles are needed to write the entire error code out.

The detailed error report would look like this:

Showing IC1 as the device with two shorted LEDs at position 6 and 7, and IC4 with one shorted LED at position 4.

Note: In an actual report there are no spaces in the output. LEDs turned off during test time cannot be tested.

8.6.4 Low-Current Diagnostic Mode

To run the open- or shorted-LED test, a test pattern must be used that will turn on each LED to be tested. This test pattern will cause a short

flicker on the screen while the test is being performed. The low-current diagnostic mode can be initiated prior to running a detailed error report to

reduce this on-screen flickering.

Note: Normally, displays using such a diagnosis mode require additional cables, resistors, and other components to reduce the current. The

AS1109 has this current-reduction capability built-in, thereby minimizing the number of external components required.

Low-current diagnostic mode can be initiated via 3 clock pulses during error-detection mode. After the falling edge of LD, a test pattern displaying

all 1s can be written to the shift register which will be used for the next error-detection test.

On the next falling edge of OEN, current is reduced to ILC. With the next rising edge of OEN the current will immediately increase to normal

levels and the detailed error report can be read out entering error-detection mode.

Input Data: 11111111 11111111 11111111 11111111 11111111

LED Status: 11111XX1 11111111 11111111 111X1111 11111111

Failure Code: 11111001 11111111 11111111 11101111 11111111

Global Flag Readout Detailed Error Report Readout

SDI

OEN

CLK

SDO

tH(L)

tSU(ERROR)

tP1

tSW(ERROR)

tP4

TFLAG SFLAG

Acquisition of Error

Status

DBit6 DBit5 DBit4 DBit3 DBit2 DBit1 DBit0 Don’t

Care

Don’t

Care

SBit6 SBit5 SBit4 SBit3 SBit2 SBit1 SBit0SBit7

New Data Input

Shorted-LED Error Report Output

OFLAG

TFLAG

tP4

tTESTING

Global Flag Readout

DBit7

For detailed timing information see Timing Diagrams on page 8.

tGSW(ERROR)

www.ams.com/LED-Driver-ICs/AS1109 Revision 1.21 15 - 24

AS1109

Datasheet - Detailed Description

Figure 18. Switching into Low-Current Diagnostic Mode Timing Diagram

8.7 Shutdown Mode

The AS1109 features a shutdown mode which can be entered via 4 clock pulses during error-detection mode. To enable the shutdown mode a 0

must be placed at SDI after the rising edge of the 3rd clock pulse.

To disable shutdown mode a 1 must be placed at SDI after the 3rd clock pulse. The shutdown/wakeup information will be latched through if

multiple AS1109 devices are in a chain. At the rising edge of the 4th clock pulse the shutdown bit will be read out and the AS1109 will shutdown

or wakeup.

Note: In shutdown mode the supply current drops down to typically 3µA.

Figure 19. Shutdown Mode Timing Diagram

OFLAGTFLAG SFLAG Don’t

Care

Re-entering Error Detection

Mode

tTESTING

Global Flag Readout

SDI

OEN

CLK

SDO

Load Internal all 1s T est

Pattern

(optional)

tH(L)

tP4

tSW(ERROR)

tP1

tSU(ERROR)

Normal Operation Current

For detailed timing information see Timing Diagrams on page 8.

tGSW(ERROR)

2µs Low-Current Diagnosis Mode

tH(L)

SDI

OEN

CLK

SDO

1 = Wakeup

0 = Shutdown

1 = Wakeup

0 = Shutdown

OFLAGTFLAG SFLAG

tP4

tSU(ERROR)

tSU(D)

www.ams.com/LED-Driver-ICs/AS1109 Revision 1.21 16 - 24

AS1109

Datasheet - Application Information

9 Application Information

9.1 Error Detection

The AS1109 features two types of error detection. The error detection can be used on-the-fly, for active LEDs, without any delay, or by entering

into low-current diagnosis mode.

9.1.1 Error Detection On-The-Fly

Error detection on-the-fly will output the status of active LEDs during operation. Without choosing an error mode this will output the temperature

flag at every input/output cycle. Triggering one clock pulse for open or two clock pulses for short detection during error detection mode outputs

the detailed open- or short-error report with the next input/output cycle (see Figure 20). LEDs that are turned off cannot be tested and their digits

at the error output must be ignored.

Figure 20. Normal Operation with Error Detection During Operation – 128 Cascaded AS1109s

Display

SDI

SDO

CLK

OEN

Current

Data1 Data2 Data3

T/O or S Error Code

Data1

T/O or S Error Code Data0

Data0 T/O or S Error Code

Data2

1024x 1024x 1024x

Clock for Error

Mode 0x/1x/2x

Rising Edge of OEN

Acquisition of Error Status

Falling Edge of LD; Error Register is copied

into Shift Register

≤ 100mA

GEFGEF

GEF = Global Error Flag

Falling Edge of LD; Error Register is copied

into Shift Register

Clock for Error

Mode 0x/1x/2x

Rising Edge of OEN

Acquisition of Error Status

Data2 Data3 Data4

www.ams.com/LED-Driver-ICs/AS1109 Revision 1.21 17 - 24

AS1109

Datasheet - Application Information

9.1.2 Error Detection with Low-Current Diagnosis Mode

This unique feature of the AS1109 uses an internal all 1s test pattern for a flicker free diagnosis of all LEDs. This error detection mode can be

started anytime, and does not require any SDI input (see Figure 21).

Figure 21. Low-Current Diagnosis Mode with Internal All 1s Test Pattern – 128 Cascaded AS1109s

Low-current diagnosis mode is started with 3 clock pulses during error detection mode. After the three pulses of CLK, a pulse of LD loads the

internal all 1s test pattern. Then OEN should be enabled for 2µs for testing. With the rising edge of OEN the test of the LEDs is stopped and

while LD is high the desired error mode can be selected with the corresponding clock pulses.

With the next data input the detailed error code will be clocked out at SDO.

Note: See Figure 22 for the use of an external test pattern.

Figure 22. Low-Current Diagnosis Mode with External Test Pattern – 128 Cascaded AS1109s

GEF

1024x1024x

Data0 Data1

Rising Edge of OEN

Acquisition of Error Status

Falling Edge of LD; Error Register is cop-

ied into Shift Register

GEF

O or S Error Code of

All 1s Test Patern Temperature Error Code

Load Internal All 1s Test Pattern

≤ 100mA ≤ 100mA

2µs Low-Current Diagnosis Mode

3x Clocks Low-

Current Mode Clock for Error Mode

1x/2x

Display

SDI

SDO

CLK

OEN

Current

≤ 0.8mA GEF = Global Error Flag

Data1 Data2

Temperature Error Code

Data2

Data1

GEF GEF

T/O or S Error Code

Data0

Rising Edge of OEN

Acquisition of Error Status

Display

SDI

SDO

CLK

OEN

1024x

3x Clocks

Low-Current

Mode Clock for Error

Mode 1x/2x

Falling Edge of LD; Error Register is cop-

ied into Shift Register

O or S Error Code

from Test Pattern

1024x

GEF = Global Error Flag

2µs Low-Current Diagnosis Mode

≤ 100mA ≤ 100mA

Current

≤ 0.8mA

Data2 Data3

External all 1s Test Pattern

www.ams.com/LED-Driver-ICs/AS1109 Revision 1.21 18 - 24

AS1109

Datasheet - Application Information

9.2 Cascading Devices

To cascade multiple AS1109 devices, pin SDO must be connected to pin SDI of the next AS1 109 (see Figure 23). At each rising edge of CLK the

LSB of the shift register will be written into the shift register SDI of the next AS1109 in the chain. Data at the SDI pin is clocked in at the rising

edge of the CLK pulse and is clocked out at the SDO pin 8.5 clock cycles later at the falling edge of the CLK pulse.

Note: When n*AS1109 devices are in one chain, n*8 clock pulses are needed to latch-in the input data.

Figure 23. Cascading AS1109 Devices

9.3 Constant Current

In LED display applications, the AS1109 provides virtually no current variations from channel-to-channel and from AS1109-to-AS1109. This is

mostly due to 2 factors:

While IOUT ≥ 50mA, the maximum current skew is less than ±2% between channels and less than ±2% between AS1109 devices.

In the saturation region, the characteristics curve of the output stage is flat (see Figure 5 on page 6). Thus, the outp ut current can be kept

constant regardless of the variations of LED forward voltages (VF).

9.4 Adjusting Output Current

The AS1109 scales up the reference current (IREF) set by external resistor (REXT) to sink a current (IOUT) at each output port. As shown in

Figure 3 on page 6 the output current in the saturation region is extremely flat so that it is possible to define it as target current (IOUT TARGET).

IOUT TARGET can be calculated by: VREXT = 1.253V (EQ 1)

IREF = VREXT/REXT (if the other end of REXT is connected to ground) (EQ 2)

IOUT TARGET = IREF*15 = (1.253V/REXT)*15 (EQ 3)

Where:

REXT is the resistance of the external resistor connected to pin REXT.

VREXT is the voltage on pin REXT.

The magnitude of current (as a function of REXT) is around 100mA at 186Ω, 50.52mA at 372Ω and 25.26mA at 744Ω. Figure 3 on page 6

shows the relationship curve between the IOUT TARGET of each channel and the corresponding external resistor (REXT).

AS1109 #n-1

SDI SDO

CLK LD OEN

SDI

CLK

OEN

AS1109 #1

SDI SDO

CLK LD OEN

AS1109 #2

SDI SDO

CLK LD OEN

www.ams.com/LED-Driver-ICs/AS1109 Revision 1.21 19 - 24

AS1109

Datasheet - Application Information

9.5 Package Power Dissipation

The maximum allowable package power dissipation (PD) is determined as:

PD(MAX) = (TJ-TAMB)/RTH(J-A) (EQ 4)

When 8 output channels are turned on simultaneously, the actual package power dissipation is:

PD(ACT) = (IDD*VDD) + (IOUT*Duty*VDS*8) (EQ 5)

Therefore, to keep PD(ACT) ≤ PD(MAX), the allowable maximum output current as a function of duty cycle is:

IOUT = {[(TJ-TAMB)/RTH(J-A)]-(IDD*VDD)}/VDS/Duty/8 (EQ 6)

Where:

TJ = 150ºC

9.6 Delayed Outputs

The AS1109 has graduated delay circuits between outputs. These delay circuits can be found between OUTNn and constant current block.

The fixed delay time is 20 ns (typ) where OUTN0 has no delay , OUTN1 has 20ns delay, OUTN2 has 40ns delay ... OUTN7 has 140ns delay. This

delay prevents large inrush currents, which reduce power supply bypass capacitor requirements when the outputs turn on (see Figure 12 on

page 9)

9.7 Switching-Noise Reduction

LED drivers are frequently used in switch-mode applications which normally exhibit switching noise due to parasitic inductance on the PCB.

9.8 Load Supply Voltage

Considering the package power dissipation limits (see EQ 4:6), the AS1109 should be operated within the range of

VDS = 0.4 to 1.0V.

For example, if VLED is higher than 5V, VDS may be so hi gh th at PD(ACT) > PD(MAX) where VDS = VLED - VF. In this case, the lowest possible

supply voltage or a voltage reducer (VDROP) should be used. The voltage reducer allows

VDS = (VLED -VF) - VDROP.

Note: Resistors or zener diodes can be used as a voltage reducer as shown in Figure 24.

Figure 24. Voltage Reducer using Resistor (Left) and Zener Diode (Right)

AS1109

VDS

Voltage Supply

}

VLED VDROP

AS1109

VDS

VLED

VDROP

V o ltage Supply

{

www.ams.com/LED-Driver-ICs/AS1109 Revision 1.21 20 - 24

AS1109

Datasheet - Package Drawings and Markings

10 Package Drawings and Markings

The product is available in a 16-pin SOIC-150, 16-pin QSOP-150, and 16-pin QFN 4x4mm package.

Figure 25. 16-pin SOIC-150 Package

Marking: YYWWRZZ.

YY WW RZZ

Last two digits of the current year Manufacturing Week Plant identifier Traceability code

Symbol Min Nom Max

A--1.75

A1 0.10 - 0.25

A2 1.25 - -

b0.31-0.51

c0.17-0.25

D - 9.90 BSC -

E - 6.00 BSC -

E1 - 3.90 BSC -

e - 1.27 BSC -

L0.40-1.27

L1 - 1.40 REF -

L2 - 0.25 BSC -

R0.07 - -

Symbol Min Nom Max

R1 0.07 -

h0.25-0.50

Θ0º - 8º

Θ1 5º - 15º

Θ20º - -

aaa - 0.10 -

bbb - 0.20 -

ccc - 0.10 -

ddd - 0.25 -

eee - 0.10 -

fff - 0.15 -

ggg - 0.15 -

N16

AS1109B

YYWWRZZ

Notes:

1. Dimensioning & tolerancing conform

to ASME Y14.5M-1994.

2. All dimensions are in millimeters.

Angles are in degrees.

www.ams.com/LED-Driver-ICs/AS1109 Revision 1.21 21 - 24

AS1109

Datasheet - Package Drawings and Markings

Figure 26. 16-pin QSOP-150 Package

Marking: YYWWRZZ.

YY WW RZZ

Last two digits of the current year Manufacturing Week Plant identifier Traceability code

Symbol Min Nom Max

A- -1.75

A1 0.10 - 0.25

A2 1.24 - -

b 0.20 - 0.30

c 0.15 - 0.25

D 4.90 BSC

E 6.00 BSC

E1 3.91 BSC

e 0.635 BSC

L 0.41 - 1.27

L1 1.04 REF

L2 0.25 BSC

R0.08 - -

R1 0.08 - -

h 0.25 - 0.51

Θ0º - 8º

Θ15º - 15º

Θ20º - -

aaa - 0.10 -

bbb - 0.20 -

ccc - 0.10 -

ddd - 0.18 -

eee - 0.10 -

fff - 0.15 -

N16

Notes:

1. Dimensioning & tolerancing conform to ASME Y14.5M-1994.

2. All dimensions are in millimeters. Angles are in degrees.

3. Datums A & B to be determined at Datum H.

AS1109B

YYWWRZZ

www.ams.com/LED-Driver-ICs/AS1109 Revision 1.21 22 - 24

AS1109

Datasheet - Package Drawings and Markings

Figure 27. 16 -pin QFN 4x4mm Package

Marking: YYWWQZZ.

YY WW QZZ

Last two digits of the current year Manufacturing Week Plant identifier Traceability code

Symbol Min Nom Max

A 0.70 0.75 0.80

A1 0 0.02 0.05

A3 0.20 REF

L 0.45 0.55 0.65

b 0.25 0.30 0.35

D 4.00 BSC

E 4.00 BSC

e 0.65 BSC

D2 2.00 2.15 2.25

E2 2.00 2.15 2.25

aaa - 0.15 -

bbb - 0.10 -

ccc - 0.10 -

ddd - 0.05 -

eee - 0.08 -

fff - 0.10 -

N16

Notes:

1. Dimensioning & tolerancing conform to ASME Y14.5M-1994.

2. All dimensions are in millimeters. Angles are in degrees.

3. Coplanarity applies to the exposed heat slug as well as the terminal.

4. Radius on terminal is optional.

5. N is the total number of terminals.

1109B

YYWW

QZZ

www.ams.com/LED-Driver-ICs/AS1109 Revision 1.21 23 - 24

AS1109

Datasheet - Ordering Information

11 Ordering Information

The device is available as the standard products shown in Table 9.

Note: All products are RoHS compliant.

Buy our products or get free samples online at www.ams.com/ICdirect

Technical Support is available at www.ams.com/Technical-Support

For further information and requests, email us at sales@ams.com

(or) find your local distributor at www.ams.com/distributor

Table 9. Ordering Information

Ordering Code Marking Description Delivery Form Package

AS1109-BSOU AS1109B Constant-Current, 8-Bit LED Driver with Diagnostics Tubes 16-pin SOIC-150

AS1109-BSOT AS1109B Constant-Current, 8-Bit LED Driver with Diagnostics Tape and Reel 16-pin SOIC-150

AS1109-BSSU AS1109B Constant-Current, 8-Bit LED Driver with Diagnostics Tubes 16-pin QSOP-150

AS1109-BSST AS1109B Constant-Current, 8-Bit LED Driver with Diagnostics Tape and Reel 16-pin QSOP-150

AS1109-BQFR AS1109B Constant-Current, 8-Bit LED Driver with Diagnostics Tray 16-pin QFN (4x4mm)

AS1109-BQFT AS1109B Constant-Current, 8-Bit LED Driver with Diagnostics Tape and Reel 16-pin QFN (4x4mm)

www.ams.com/LED-Driver-ICs/AS1109 Revision 1.21 24 - 24

AS1109

Datasheet - Ordering Information

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reserved. The material herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the

All products and companies mentioned are trademarks or registered trademarks of their respective companies.

Disclaimer

Devices sold by ams AG are covered by the warranty and patent indemnification provisions appearing in its Term of Sale. ams AG makes no

warranty, express, statutory, implied, or by description regarding the information set forth herein or regarding the freedom of the described

devices from patent infringement. ams AG reserves the right to change specifications and prices at any time and without notice. Therefore, prior

to designing this product into a system, it is necessary to check with ams AG for current information. This product is intended for use in normal

commercial applications. Applications requiring extended temperature range, unusual environmental requirements, or high reliability

applications, such as military, medical life-support or life-sustaining equipment are specifically not recommended without additional processing

by ams AG for each application. For shipments of less than 100 parts the manufacturing flow might show deviations from the standard

production flow, such as test flow or test location.

The information furnished here by ams AG is believed to be correct and accurate. However, ams AG shall not be liable to recipient or any third

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