AS1112

austriamicrosystems AG
is now
ams AG
The technical content of this austriamicrosystems datasheet is still valid.
Contact information:
Headquarters:
ams AG
Tobelbaderstrasse 30
8141 Unterpremstaetten, Austria
Tel: +43 (0) 3136 500 0
e-Mail: [email protected]
Please visit our website at www.ams.com
Datas h eet
A S111 2
1 6- C h a n n e l L E D D ri v er w it h D o t Co rr e c ti o n a n d G r ey s c a le P W M
1 General Description
2 Key Features
16 Channels
Greyscale PWM Control: 12-Bit (4096 Steps)
Dot Correction: 6-Bit (64 Steps)
Drive Capability (Constant-Current Sink): 0 to 100mA
LED Power Supply Voltage: Up to 15V
Supply Voltage Range: 3.0 to 5.5 V
The open & short LED detection function indicates a broken, shorted
or disconnected LED at one or more of the outputs. The overtemperature flag indicates that the device is in an overtemperature condition.
SPI-Compatible Serial Interface
Table 1. Standard Products
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Controlled In-Rush Current
Data Transfer & PWM Clock Rate: up to 30 MHz
CMOS Level I/O
Diagnostic Features
- LED Open/Short Detection
- Overtemperature Flag
32-pin TQFN 5x5 mm Package
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The dot correction circuitry adjusts the brightness variations between
the AS1112 channels and other LED drivers. Greyscale control and
dot correction circuitry are accessible via the SPI-compatible serial
interface. A single external resistor sets the maximum current value
of all 16 channels.
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The AS1112 is a 16-channel, constant current-sink LED driver. Each
of the 16 channels can be individually adjusted by 4096-step
greyscale PWM brightness control and 64-step constant-current sink
(dot correction).
Model
Power-Down
TEST pin
Output Delay
AS1112
Yes
Connect to GND
Yes
AS1112B
No
Connect to VCC
Yes
AS1112C
No
Connect to VCC
No
An additional power-down pin puts the AS1112 into a 40nA standbymode.
3 Applications
The AS1112 is available in a 32-pin TQFN 5x5 mm package.
The device is ideal for mono-, multi-, and full-color LED displays,
LED signboards, and display backlights.
Figure 1. AS1112 - Block Diagram
1 CLK
Max OUTn
Current
24
OEN
Greyscale
Counter
Control
ch
3
Te
Thermal
Flag
12-Bit Greyscale
PWM Control
Dot Correction
Register 5
6-Bit Dot
Correction
0
Open
LED
Detect
22
OUT0
5
Greyscale
12 Register 23
12-Bit Greyscale
PWM Control
Dot Correction
6 Register 11
6-Bit Dot
Correction
Delay*
x1
OUT1
.
.
.
Open&Short LED Detection
Constant Current
Driver
Control
21
Greyscale
180 Register191
12-Bit Greyscale
PWM Control
Dot Correction
90 Register 95
6-Bit Dot
Correction
XERR
30
GND
4
Constant Current
Driver
Control
.
.
Input
Shift
Register
Delay*
x0
Open&Short LED Detection
.
MODE
VCC
Constant Current
Driver
Greyscale
0 Register 11
Input
Shift
Register
Status
Open LED Detect,
Overtemperature
Flag, Dot
Correction Data
27
29 PD
Control
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GSCLK
31
32 LD
VREF =
1.24V
ca
26
IREF
2 SDI
Delay*
x15
OUT15
Open&Short LED Detection
23
AS1112
SDO
* not for AS1112C
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Revision 1.13
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AS1112
Datasheet - P i n o u t
4 Pinout
Pin Assignments
XTEST 25
IREF 26
N/C 28
VCC 27
N/C 29
GND 30
LD 32
OEN 31
TEST 25
IREF 26
N/C 28
VCC 27
PD 29
GND 30
LD 32
OEN 31
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Figure 2. Pin Assignments (Top View)
CLK
1
24 GSCLK
CLK
1
24 GSCLK
SDI
2
23 SDO
SDI
2
23 SDO
MODE
3
22 XERR
MODE
3
OUT0
4
21 OUT15
OUT0
4
OUT1
5
20 OUT14
OUT1
5
OUT2
6
19 OUT13
OUT2
6
OUT3
7
18 OUT12
OUT3
7
OUT4
8
17 OUT11
OUT4
8
Thermal
Pad
20 OUT14
19 OUT13
18 OUT12
17 OUT11
16 OUT10
15 OUT9
14 OUT8
Description
Serial Data Shift Clock
Serial Data Input
Mode Select input with internal pulldown
MODE = GND: Selects greyscale mode (see Setting Greyscale Brightness on page 12).
MODE = VCC: Selects dot correction mode (see Setting Dot Correction on page 11).
Constant-Current Outputs 0:7
Constant-Current Outputs 8:15
Error Output
0 = LED open detection or overtemperature condition is detected.
1 = Normal operation.
Serial Data Output
Greyscale Clock. Reference clock for greyscale PWM control
Test Pin. This pin must be connected to GND (AS1112) to ensure normal operation.
Test Pin. This pin must be connected to VCC (AS1112B, AS1112C) to ensure normal operation.
Reference Current Terminal
Power Supply Voltage
This pin must not be connected.
Power Down input with internal pulldown (AS1112)
0 = normal operation mode
1 = powerdown mode
Not Connected (AS1112B, AS1112C)
Ground
Blank Outputs
0 = OUTn outputs are controlled by the greyscale PWM control.
1 = OUTn outputs are forced off; the greyscale counter is reset.
Data Latch. The internal connections are switched by pin MODE.
For LD (MODE = GND), the greyscale register receives new data.
For LD (MODE = VCC), the dot correction register receives new data.
Thermal Pad. This pin must be connected to GND to ensure normal operation.
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SDO
GSCLK
TEST
XTEST
IREF
VCC
N/C
13 N/C
23
24
11 OUT7
XERR
12 N/C
22
OUT5
OUT0:OUT7
OUT8:OUT15
9
4:11
14:21
ch
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25
26
27
12,13,28
21 OUT15
33
10 OUT6
MODE
16 OUT10
3
15 OUT9
Pin Name
CLK
SDI
14 OUT8
Pin Number
1
2
13 N/C
11 OUT7
OUT5
Table 2. Pin Descriptions
12 N/C
9
10 OUT6
Pin Descriptions
Thermal
Pad
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33
22 XERR
AS1112B/C
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AS1112
Te
29
PD
30
N/C
GND
31
OEN
32
LD
33
Thermal Pad
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Revision 1.13
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AS1112
Datasheet - A b s o l u t e M a x i m u m R a t i n g s
5 Absolute Maximum Ratings
Stresses beyond those listed in Table 3 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 Recommended Operating Conditions on page 4 is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
Table 3. Absolute Maximum Ratings
Min
Max
Units
Comments
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Parameter
Electrical Parameters
-0.3
6
V
-0.3
VCC + 0.3
V
VOUT0 : VOUT15 to GND
-0.3
15
V
110
mA
100
mA
Norm: JEDEC 78
kV
Norm: MIL 883 E method 3015
°C/W
For more information about thermal metrics, see
application note AN01 Thermal Characteristics.
Output Current (DC)
Input Current (latch-up immunity)
-100
Electrostatic Discharge
+/- 2
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Electrostatic Discharge HBM
Thermal Information
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VCC to GND
All other pins to GND
Junction to ambient thermal resistance
37
Temperature Ranges and Storage Conditions
Junction Temperature
Storage Temperature Range
-55
ºC
ºC
+260
Package Body Temperature
Humidity non-condensing
+110
+150
5
%
3
Represents a max. floor life time of 168h
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Moisture Sensitive Level
85
ºC
The reflow peak soldering temperature (body temperature)
specified is in accordance with IPC/JEDEC J-STD020“Moisture/Reflow Sensitivity Classification for NonHermetic Solid State Surface Mount Devices”.
The lead finish for Pb-free leaded packages is matte tin
(100% Sn).
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Revision 1.13
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AS1112
Datasheet - R e c o m m e n d e d O p e r a t i n g C o n d i t i o n s
6 Recommended Operating Conditions
Table 4. DC Characteristics
Min
TAMB
Operating Temperature Range
VCC
Supply Voltage
VOUT
Voltage Applied to Output
(OUT0:OUT15)
VIH
High-Level Input Voltage
0.8 x
VCC
VIL
Low-Level Input Voltage
GND
IOH
High-Level Output Current
VCC = 5 V at SDO
-1.0
IOL
Low-Level Output Current
VCC = 5 V at SDO, XERR
1.0
ICOC
Constant Output Current
OUT0:OUT15
Typ
Max
Unit
-40
85
°C
3
5.5
V
15
V
VCC
V
0.2 x
VCC
V
mA
mA
100
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Conditions
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Parameter
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Symbol
mA
Table 5. AC Characteristics – VCC = 3 V to 5.5 V, TAMB = -40 to 85°C (unless otherwise specified)
Symbol
Parameter
Conditions
fCLK
Data Shift Clock Frequency
CLK
fGSCLK
Greyscale Clock Frequency
GSCLK
tWH0/tWL0
2
20
ns
1
12
3
12
LD = 1
OEN Pulse Duration
OEN = 1
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tSU3
tH0
ch
tH1
ni
tSU4
tH2
Hold Time
2
1
MODE, CLK
MODE, LD
4
4
OEN, GSCLK
CLK, SDI
LD, CLK
12
2
12
12
1
12
CLK, MODE
4
4
LD, MODE
tH4
GSCLK, OEN
ns
12
3
tH3
Te
MHz
ns
LD Pulse Duration
Setup Time
30
20
tWH2
tSU2
MHz
ns
GSCLK = 1/0
CLK, LD
Unit
30
16
GSCLK Pulse Duration
tSU1
Max
ns
tWH1/tWL1
SDI, CLK
Typ
16
CLK = 1/0
tSU0
1.
2.
3.
4.
1
CLK Pulse Duration
tWH3
Min
12
ns
12
2
12
See Figure 12 on page 12.
See Figure 16 on page 14.
See Figure 14 on page 13.
See Figure 9 on page 8.
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Revision 1.13
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AS1112
Datasheet - E l e c t r i c a l C h a r a c t e r i s t i c s
7 Electrical Characteristics
VCC = +3.0 to +5.5V, Typical values are at TAMB = 25°C, VCC = 5V (unless otherwise specified). All limits are guaranteed. The parameters with
min and max values are guaranteed with production tests or SQC (Statistical Quality Control) methods.
Table 6. Electrical Characteristics
Symbol
Parameter
Condition
Min
TJ
Operating Junction Temperature
VOH
High-Level Output Voltage
IOH = -1mA, SDO
VOL
Low-Level Output Voltage
IOL = 1mA, SDO, XERR
VCC -0.5
+125
°C
V
0.5
-1
VIN = VCC; pin MODE, PD
VIN = GND; pin MODE, PD
Unit
1
100
-1
1.2
3
All outputs off, RIREF = 1.3kΩ
4
10
All outputs on, RIREF = 1.3kΩ
15
20
All outputs on, RIREF = 640Ω
30
40
Power Down Current
only AS1112
40
ICOC
Constant Output Current
All outputs on, VOUT = 2V,
RIREF = 640Ω
ILEAK
Leakage Output Current
All outputs off, VOUT = 15V,
RIREF = 640Ω, OUT0:OUT15
20
VOUT = 2V, RIREF = 640Ω, OUT0:OUT15
±3
±4.5
VOUT = 2V, RIREF = 480Ω, OUT0:OUT15
±3
±4.5
Device to device, average current from
OUT0:OUT15, RIREF = 1920Ω (20 mA),
VCC = 5.5V, VOUT = 2V
±3
±4.5
Device to device, average current from
OUT0:OUT15, RIREF = 480Ω (80 mA),
VCC = 5.5V, VOUT = 2V
±3
±4.5
VOUT = 2V, RIREF = 640Ω OUT0:OUT15
ICC
Supply Current
IPD
∆ICOC
Constant Current Error
∆ILNR
TTEF
±2.5
±1
±2.5
VOUT = 2 to 4V, RIREF = 640Ω,
OUT0:OUT15
±0.1
±0.5
VOUT = 2 to 4V, RIREF = 480Ω,
OUT0:OUT15
±0.1
±0.5
mA
nA
mA
nA
%
%/V
%/V
1
150
ºC
1
125
ºC
VCC = 5V
2.8
V
VCC = 3V
1.7
V
Junction temperature
TTWF
Thermal Warn Flag Threshold
Junction temperature
VLSD
LED Short Detection Threshold
VLOD
LED Open Detection Threshold
VIREF
Reference Voltage Output
ch
69
±1
Thermal Error Flag Threshold
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VOUT = 2V, RIREF = 480Ω OUT0:OUT15
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Load Regulation
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∆ILDR
Line Regulation
54
µA
1
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All outputs off, RIREF = 10kΩ
V
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Input Current
Max
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-40
VIN = VCC or GND; Pins OEN, TEST,
GSCLK, CLK, SDI, LD
I
Typ
RIREF = 640Ω
1.20
0.3
0.4
V
1.24
1.28
V
1. Specified by design. Not tested.
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Revision 1.13
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AS1112
Datasheet - E l e c t r i c a l C h a r a c t e r i s t i c s
Switching Characteristics
VCC = +3.0 to +5.5V, TAMB = -40 to +85ºC. Typical values are at TAMB = 25°C, VCC = 5V (unless otherwise specified).
Table 7. Switching Characteristics
Conditions
tR0
Rise Time
tR1
tF1
8
OUTn, DC = 3FHEX
20
SOUT
8
OUTn, DC = 3FHEX
20
1
tPD0
CLK, SDO
tPD1
OEN, OUT0
Propagation Delay Time
15
2
30
2
OUTn, XERR (includes error detection time, see
Figure 10 on page 10)
Max
tPD3
GSCLK, OUT0
3
Average Output Delay Time
tD
OUTn, OUTn+1
Unit
ns
ns
ns
1000
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tPD2
Typ
SDO
tF0
Fall Time
Min
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Parameter
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Symbol
2
30
2, 3
30
ns
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1. See Figure 14 on page 13.
2. See Figure 16 on page 14.
3. Only for AS1112 and AS1112B.
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Revision 1.13
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AS1112
Datasheet - Ty p i c a l O p e r a t i n g C h a r a c t e r i s t i c s
8 Typical Operating Characteristics
TAMB = 25ºC (unless otherwise specified).
Figure 3. Output Current vs. VDS; VDD = 5V
Figure 4. Output Current vs. VDS; VDD = 5V
120
110
70
60
50
Iout = 60mA (640Ω)
Iout = 40mA (1kΩ)
40
30
20
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Iout = 80mA (480Ω)
Iout = 100mA (390Ω)
100
90
80
Iout = 80mA (480Ω)
70
60
50
Iout = 60mA (640Ω)
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Iout = 100mA (390Ω)
100
90
80
IOUT (mA) .
IOUT (mA) .
120
110
Iout = 40mA (1kΩ)
40
30
20
Iout = 15mA (2.7kΩ)
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Iout = 15mA (2.7kΩ)
10
0
10
0
0
2
4
6
8
0
10
0.5
1
Figure 5. Output Current vs. VDS; VDD = 3V
90
2.5
3
90
70
Iout = 80mA (480Ω)
80
70
Iout = 60mA (640Ω)
60
50
IOUT (mA) .
IOUT (mA) .
2
Figure 6. Output Current vs. VDS; VDD = 3V
Iout = 80mA (480Ω)
80
Iout = 40mA (1kΩ)
40
30
Iout = 60mA (640Ω)
60
50
Iout = 40mA (1kΩ)
40
30
20
20
Iout = 15mA (2.7kΩ)
10
Iout = 15mA (2.7kΩ)
10
0
ca
0
0
2
4
6
8
10
0
0.5
1
VDS (V)
2
2.5
3
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Figure 8. Output Current vs. Dot Correction Value;
90
80
ch
100
1.5
VDS (V)
Figure 7. Output Current vs. REXT;
Iout = 80mA (480Ω)
IOUT (mA) .
70
Te
IOUT (mA) .
1.5
VDS (V)
VDS (V)
10
60
50
40
30
Iout = 40mA (1kΩ)
20
10
1
0
0
1
2
3
4
5
6
7
8
9
10
0
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9
18
27
36
45
54
63
Dot Correction Value
REXT (kOhm)
Revision 1.13
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AS1112
Datasheet - D e t a i l e d D e s c r i p t i o n
9 Detailed Description
Serial Interface
The AS1112 features a serial interface (CLK, SDI, SDO, LD, OEN and MODE), which can be connected to microcontrollers or digital signal processors in various configurations.
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The rising edge of the CLK signal shifts data from pin SDI to the internal register. After all data is clocked in, the serial data is latched into the
internal registers at the rising edge of the LD signal.
Note: All data is clocked in with the MSB first.
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Multiple AS1112 devices can be cascaded by connecting the SDO pin of one device with pin SDI of the next device (see Figure 17 on page 15).
The SDO pin can also be connected to the microcontroller to receive status information from the AS1112. The serial data format is 96-bit or 192bit wide, depending on mode of the device (see LD on page 2).
Figure 9. Serial Data Input Timing Diagram
MODE
Greyscale Mode
Data Input Cycle
tH3
LD
SDI
DCn-1
LSB
DCn
MSB
SDO
1
DCn-1
MSB
DCn-1
MSB-1
tSU3
DCn
LSB
tH2
CLK
Dot Correction Mode
Data Input Cycle
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Dot Correction Mode
Data Input Cycle
96
DCn-1
LSB
tH3
GSn
MSB
GSn
LSB
tSU2
tSU2
1
DCn
MSB
DCn-1
MSB-1
DCn+1
MSB
192
X
X
1
SID
MSB
2
X
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Error Information Output
ni
The open-drain output pin XERR indicates if the device is in one of the two error conditions: overtemperature flag or open LED detect. During
normal operation, the internal transistor connected to pin XERR is turned off and the voltage on XERR is pulled up to VCC through an external
pullup resistor.
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If an overtemperature or open LED condition is detected, the internal transistor is switched on, and XERR is pulled to GND. Because XERR is an
open-drain output, multiple AS1112 devices can be ORed together and pulled up to VCC with a single pullup resistor (see Figure 17 on page 15).
This reduces the number of signals needed to report a system error.
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To differentiate the overtemperature flag from the open LED detect flag from pin XERR, the open LED detect flag can be masked out by setting
OEN = 1 (see Table 8).
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Revision 1.13
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AS1112
Datasheet - D e t a i l e d D e s c r i p t i o n
Table 8. XERR Truth Table
Error Condition
T
e
m
p
TJ < TTEF
TJ > TTEF
Short
LED
Detect
Status
OEN Mode XERR
OUTn > VLOD
0
Don't Care
0
Don't Care
0
0
1
normal
OUTn < VLOD
0
Don't Care
1
Don't Care
0
0
0
open error
OUTn > VLOD
1
Don't Care
0
Don't Care
0
0
0
OUTn < VLOD
1
Don't Care
1
Don't Care
0
0
0
TJ > TTEF
Don't Care
0
Don't Care
Don't Care
Don't Care
1
0
1
TJ < TTEF
Don't Care
1
Don't Care
Don't Care
Don't Care
1
0
0
TJ > TTWF
Don't Care
Don't Care
0
Don't Care
Don't Care
1
1
1
TJ < TTWF
Don't Care
Don't Care
1
Don't Care
Don't Care
1
1
0
normal
temp error
normal
temp. warn
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Overtemperature Error/Warning Flags
temp. error
open & temp.
error
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O
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n
Thermal
OUTn Voltage Error Flag
Selected Mode
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Temp.
Error Information
Thermal Open LED
Warning
Detect
Flag
The AS1112 provides a overtemperature circuit to indicate that the device is in an overtemperature condition. If the device junction temperature
(TJ) exceeds the threshold temperature (150°C typ), the overtemperature circuit trips and pulls XERR to ground. The overtemperature flag status can be read out from the AS1112 status register.
To prevent an overtemperature condition the AS1112 offers an temperature warning flag at 125°C typical. This flag can be used to take precautions (e.g. start an external cooling) against a overtemperature condition.
Open LED Detection
The AS1112 integrated open LED detection circuit reports an error if any of the 16 LEDs is open or disconnected from the circuit. The open LED
detection circuit trips when the error detection is activated (see Table 8) and the voltage at OUTn is less than VLOD.
Note: The voltage at each OUTn is sampled 1µs after being switched on. Please refer to Figure 10.
The open LED detection circuit also pulls XERR to GND when tripped. The open LED status of each channel can also be read out from the
AS1112 status information data (SID) during a greyscale data input cycle.
Shorted LED Detection
The AS1112 integrated shorted LED detection circuit detects if any of the 16 LEDs is short-circuited. The shorted LED detection circuit trips when
the error detection is activated and the voltage at OUTn is higher than VLSD.
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Note: The voltage at each OUTn is sampled 1µs after being switched on. Please refer to Figure 10.
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The shorted LED status of each channel can only be read out from the AS1112 status information data (SID) during a greyscale data input cycle.
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Revision 1.13
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AS1112
Datasheet - D e t a i l e d D e s c r i p t i o n
Figure 10. Error Detection Timing (GS=FFFFHEX, DC=3FHEX)
LD
>1µs
GSCLK
LODn, LSDn
Error
Detection
Start
LODn+1, LSDn+1
Error
Detection
End
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SID
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OEN
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Note: The rising edge of LD latches new data into the internal registers depending on the logic level of the pin MODE. If the pin MODE is tied
GND, the greyscale registers are updated. If the pin MODE is tied to VCC, the dot correction registers are updated.
Delay Between Outputs (only for AS1112 and AS1112B)
The AS1112 uses graduated delay circuits between OUTn outputs. These circuits are contained in the constant-current driver block of the
AS1112 (see Figure 1 on page 1). The average-delay time is 30ns (typ).
The maximum delay is 450ns (typ) from OUT0 to OUT15. The delay scheme works by switching on and switching off each output channel. Thus
the on/off time of each channel is the same regardless of the delay. These delays prevent large inrush currents and switching noise that can
reduce bypass capacitance when the outputs are switched on.
OUTn Enable
All OUTn channels can be collectively switched off with one signal. When OEN is set to 1, all OUTn channels are disabled, regardless of the
device logic operations. The greyscale counter is also reset when OEN is set to 1.
When OEN is set to 0, all OUTn channels are in normal operation.
Table 9. Pin OEN Truth Table
OEN
OUT0:OUT15
0
Normal Operation
Disabled
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1
Setting Maximum Channel Current
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The maximum output current per channel is programmed by a single resistor, RIREF, which is placed between pin IREF and GND. The voltage
on pin IREF is set by an internal band gap VIREF (1.24V typ). The maximum channel current is equivalent to the current flowing through RIREF
multiplied by a factor of 31.5. The maximum output current is calculated as:
IMAX =
VIREF
x 31.5
(EQ 1)
RIREF
Where:
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VIREF = 1.24V;
RIREF = User-selected external resistor.
Figure 7 on page 7 shows the maximum output current IOUT versus RIREF, where RIREF is the value of the resistor between IREF terminal to
GND, and IOUT is the constant output current of OUT0:OUT15.
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AS1112
Datasheet - D e t a i l e d D e s c r i p t i o n
Power Dissipation
To ensure proper operation of the device, the total power dissipation of the AS1112 must be below the power dissipation rating of the device
package. Total power dissipation is calculated as:
PD = (VCC x ICC) + (VOUT x IMAX x n x
DCn
dPWM)
63
(EQ 2)
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Where:
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VCC is the device supply voltage;
ICC is the device supply current;
VOUT is the device OUTn voltage when driving LED current;
IMAX is the LED current adjusted by RIREF;
DCn is the maximum dot correction value for OUTn;
n is the number of OUTn driving LED at the same time;
dPWM is the duty cycle defined by pin OEN or the greyscale PWM value.
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Operating Modes
The AS1112 operates in two modes (see Table 10). Greyscale operating mode (see Figure 14 on page 13) and the shift registers are in reset
state at power-up.
Table 10. Operating Modes
Mode
0
1
Input Shift Register
Operating Mode
192-bit
Greyscale PWM Mode
96-bit
Dot Correction Data Input Mode
Setting Dot Correction
The AS1112 can perform independent fine-adjustments to the output current of each channel, i.e., dot correction. Dot correction is used to adjust
brightness deviations of LEDs connected to the output channels (OUT0:OUT15).
The device powers up with the following default seetings: DC = 63 and GS = 4095.
The 16 channels can be individually programmed with a 6-bit word. The channel output can be adjusted in 64 steps from 0 to 100% of the maximum output current (IMAX). The output current for each OUTn channel can be calculated as:
IOUTn = IMAX x
(EQ 3)
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Where:
DCn
63
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IMAX is the maximum programmable output current for each output;
DCn is the programmed dot correction value for output (DCn = 0 to 63);
n = 0 to 15
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Dot correction data are simultaneously entered for all channels. The complete dot correction data format consists of 16 x 6-bit words, which
forms a 96-bit serial data packet (see Figure 11). Channel data is put on one by one, and the data is clocked in with the MSB first.
Figure 11. Dot Correction Data Packet Format
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MSB
95
DC15.5
...
LSB
90
89
DC15.0
DC14.5
DC OUT15
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...
DC OUT14:DC OUT1
Revision 1.13
6
5
DC1.0
DC0.5
0
...
DC0.0
DC OUT0
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AS1112
Datasheet - D e t a i l e d D e s c r i p t i o n
Figure 12. Dot Correction Data Input Timing Diagram
Dot Correction Mode
Data Input Cycle n
Dot Correction Mode
Data Input Cycle n +1
VCC
MODE
GND
DCn-1
LSB
DCn
MSB
tSU0
CLK
DCn
MSB-1
DCn
MSB-2
DCn
LSB+1
DCn
LSB
DCn+1
MSB
tWH0
1
2
1
95
96
1
DCn-1
MSB
SDO
DCn-1
MSB-1
DCn-1
MSB-2
DCn-1
LSB+1
DCn-1
LSB
DCn
MSB-1
DCn
MSB
tWH2
tSU1
2
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tWL0
DCn+1
MSB-1
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SDI
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tH1
DCn
MSB-2
LD
Setting Greyscale Brightness
The brightness of each channel output can be adjusted using a 12 bits-per-channel PWM control scheme which results in 4096 brightness steps,
from 0% to 100% brightness. The brightness level for each output is calculated as:
GSn
x 100
4095
%Brightness =
Where:
(EQ 4)
GSn is the programmed greyscale value for OUTn (GSn = 0 to 4095);
n = 0 to 15 greyscale data for all outputs.
The device powers up with the following default seetings: GS = 4095 and DC = 63.
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The input shift register shifts greyscale data into the greyscale register for all channels simultaneously. The complete greyscale data format consists of 16 x 12 bit words, which forms a 192-bit wide data packet (see Figure 13).
Note: The data packet must be clocked in with the MSB first.
MSB
180
ch
191
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Figure 13. Greyscale Data Packet Format
GS15.11
...
GS15.0
LSB
179
GS14.11
GS OUT14:GS OUT1
11
GS1.0
GS0.11
0
...
GS0.0
GS OUT0
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GS OUT15
...
12
When pin MODE is tied to GND, the AS1112 enters greyscale data input mode. The device switches the input shift register to 192-bit width. After
all data is clocked in, the rising edge of the LD signal latches the data into the greyscale register (see Figure 14).
All greyscale data in the input shift register is replaced with status information data (SID) after latching into the greyscale register.
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AS1112
Datasheet - D e t a i l e d D e s c r i p t i o n
Figure 14. Greyscale Data Input Timing Diagram
Dot Correction Mode
Data Input Cycle
1st Greyscale Mode
Data Input Cycle After Dot Correction Input
Following Greyscale Mode
Data Input Cycle
tH3
tSU3
LD
tWH2
SDI
GSn
LSB
tH2
tSU2
CLK
1
DCn-1
MSB
GSn+1
LSB
tPD0
192
1
192
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DCn-1
MSB-1
SDO
tSU1
tH0
96
GSn+1
MSB
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GSn
MSB
DCn-1
LSB
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MODE
x
x
SIDn
MSB-1
SIDn
MSB
x
SIDn
MSB-2
SIDn
LSB
SIDn
MSB
Status Information Data (SID)
The AS1112 contains an integrated status information register, which can be accessed in greyscale mode (MODE = GND). Once the LD signal
latches the data into the greyscale register, the input shift register data is replaced with status information data (see Figure 15).
Open, shorted LED, temperature warning and overtemperature flags as well as the dot-correction registers can be read out at pin SDO. The status information data packet is 192 bits wide. Bits 191:176 and 31:16 contain the open LED detection status of each channel (either 191:176 or
31:16 can be used for readout). Bit 175 contains the thermal error flag status. Bit 174 contains the temperature warning flag. Bits 167:72 contain
the data of the dot-correction register. Bit 15:0 contains the LED shorted flags. The remaining bits are reserved. The complete status information
data packet is shown in Figure 15.
Figure 15. Status Information Data Packet Format
191
LOD15
...
Open LED
Detect Data
175
174
LOD0
TEF
TWF
...
168
167
X
DC15.
Overtemperature
Flag
...
72
71
DC0.
X
...
LSB
16:31
0:15
LOD
LSD
DC Values
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Description
LED Short Detection, LSD
LED Open Detection (Optional, same as bits 176:191), LOD
Undefined
Dot Correction Readback (16 x 6 Bit)
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Bit #
0:15
16:31
32:71
72:167
176
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MSB
Bit #
168:173
174
175
176:191
Description
Undefined
Temperature Warning Flag (TWF, 125ºC, typ)
Temperature Error Flag (TEF, 150ºC, typ)
LED Open Detection, LOD
Greyscale PWM Operation
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The falling edge of the OEN signal initiates a greyscale PWM cycle. The first GSCLK pulse after the falling edge of OEN increments the
greyscale counter by one and switches on any OUTn whose greyscale value does not equal zero. Each subsequent rising edge of GSCLK increments the greyscale counter by one.
The AS1112 compares the greyscale value of each OUTn channel with the greyscale counter value. All OUTn whose greyscale values equal the
counter values are switched off. A OEN = 1 signal after 4096 GSCLK pulses resets the greyscale counter to zero and completes a greyscale
PWM cycle (see Figure 16).
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AS1112
Datasheet - D e t a i l e d D e s c r i p t i o n
Figure 16. Greyscale PWM Cycle Timing Diagram
Greyscale
PWM
Cycle n+1
Greyscale PWM
Cycle n
OEN
tWL1
tWH1
tPD1
3
4096
tPD3
tPD3
n x tD
tPD3 + n x tD
tPD1 + tD
OUT1
Current
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...
...
...
...
tPD1 + 15 x tD
OUT15
Current
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1
OUT0
Current
tSU4
tWH3
lv
GSCLK
tH4
tPD2
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XERR
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Revision 1.13
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AS1112
Datasheet - D e t a i l e d D e s c r i p t i o n
Serial Data Transfer Rate
Figure 17 shows a cascaded arrangement AS1112 devices connected to a controller, building a basic module of an LED display system.
Figure 17. Cascaded Configuration
VLED
VLED
VLED
...
100kΩ
OUT0
VLED
...
OUT15
OUT0
...
OUT15
SIN
SDI
SDO
XERR
SDI
SDO
VCC
XERR
VCC
XERR
CLK
VCC
LD
GSCLK
VCC
CLK
AS1112
100nF
LD
GSCLK
TEST
GSCLK
MODE
GND
MODE
MODE
AS1112
100nF
TEST
GND
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OEN
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CLK
LD
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VCC
OEN
SOUT
OEN
IREF
Controller
IREF
6
The maximum number of cascading AS1112 devices depends on the application system and is in the range of 40 devices. The minimum frequency needed can be calculated by the following equations:
fGSCLK = 4096 x fUPDATE
Where:
(EQ 5)
fGSCLK is the minimum frequency needed for GSCLK;
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fUPDATE is the update rate of whole cascaded system.
fCLK = 193 x fUPDATE x n
ni
Where:
(EQ 6)
fCLK is the minimum frequency needed for CLK and SIN;
fUPDATE is the update rate of whole cascaded system;
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n is the number of cascaded of AS1112 devices.
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Revision 1.13
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AS1112
Datasheet - P a c k a g e D r a w i n g s a n d M a r k i n g s
10 Package Drawings and Markings
Figure 19. Packaging Code YYWWIZZ
WW
manufacturing week
I
ZZ
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YY
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Figure 18. 32-pin TQFN 5x5 mm Marking
plant identifier
free choice / traceability code
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last two digits of the current year
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Revision 1.13
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AS1112
Datasheet - P a c k a g e D r a w i n g s a n d M a r k i n g s
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Figure 20. 32-pin TQFN 5x5 mm Package
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Revision 1.13
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AS1112
Datasheet - O r d e r i n g I n f o r m a t i o n
11 Ordering Information
The device is available as the standard products shown in Table 11.
Table 11. Ordering Information
Description
Delivery Form
Package
AS1112-BQFT
AS1112
16-Channel LED Driver with Dot Correction and Greyscale PWM
with Active-High TEST Input and Power-Down Mode
Tape and Reel
32-pin TQFN 5x5 mm
AS1112B-BQFT
AS1112B
16-Channel LED Driver with Dot Correction and Greyscale PWM
with Active-Low XTEST Input and without Power-Down Mode
Tape and Reel
32-pin TQFN 5x5 mm
AS1112C-BQFT
AS1112C
16-Channel LED Driver with Dot Correction and Greyscale PWM
with Active-Low XTEST Input, without Power-Down Mode and
without Output Delay
Tape and Reel
32-pin TQFN 5x5 mm
Note: All products are RoHS compliant and austriamicrosystems green.
Buy our products or get free samples online at ICdirect: http://www.austriamicrosystems.com/ICdirect
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Technical Support is found at http://www.austriamicrosystems.com/Technical-Support
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Marking
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Ordering Code
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For further information and requests, please contact us mailto:[email protected]
or find your local distributor at http://www.austriamicrosystems.com/distributor
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Revision 1.13
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AS1112
Datasheet
Copyrights
Copyright © 1997-2012, austriamicrosystems AG, Tobelbaderstrasse 30, 8141 Unterpremstaetten, Austria-Europe. Trademarks Registered ®.
All rights reserved. The material herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of
the copyright owner.
All products and companies mentioned are trademarks or registered trademarks of their respective companies.
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Disclaimer
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Devices sold by austriamicrosystems AG are covered by the warranty and patent indemnification provisions appearing in its Term of Sale.
austriamicrosystems 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. austriamicrosystems 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 austriamicrosystems 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 austriamicrosystems 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.
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The information furnished here by austriamicrosystems AG is believed to be correct and accurate. However, austriamicrosystems AG shall not
be liable to recipient or any third party for any damages, including but not limited to personal injury, property damage, loss of profits, loss of use,
interruption of business or indirect, special, incidental or consequential damages, of any kind, in connection with or arising out of the furnishing,
performance or use of the technical data herein. No obligation or liability to recipient or any third party shall arise or flow out of
austriamicrosystems AG rendering of technical or other services.
Headquarters
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Contact Information
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austriamicrosystems AG
Tobelbaderstrasse 30
A-8141 Unterpremstaetten, Austria
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Tel: +43 (0) 3136 500 0
Fax: +43 (0) 3136 525 01
For Sales Offices, Distributors and Representatives, please visit:
http://www.austriamicrosystems.com/contact
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