AS1112
16-Channel LED Driver with Dot Correction and
Greyscale PWM
D a ta s h e e t
1 General Description
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 con-
trol and 64-step constant-current sink (dot correction).
The dot correction circuitry adjusts the brightness varia-
tions between the AS1112 channels and other LED driv-
ers. Greyscale control and dot correction circuitry are
accessible via the SPI-compatible serial interface. A sin-
gle external resistor sets the maximum current value of
all 16 channels.
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.
Table 1. Standard Products
Model
AS1112
AS1112B
Power-Down
Yes
No
TEST pin
Connect to GND
Connect to V
CC
2 Key Features
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16 Channels
Greyscale PWM Control: 12-Bit (4096 Steps)
Dot Correction: 6-Bit (64 Steps)
Drive Capability (Constant-Current Sink): 0 to 80mA
LED Power Supply Voltage: Up to 15V
Supply Voltage Range: 3.0 to 5.5 V
SPI-Compatible Serial Interface
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
!
An additional power-down pin puts the AS1112 into a
40nA standby-mode.
The AS1112 is available in a 32-pin TQFN 5x5 mm
package.
Figure 1. Block Diagram
1 CLK
26
I
REF
24
GSCLK
31
OEN
Status
Open LED Detect,
Overtemperature
Flag, Dot
Correction Data
3
MODE
3 Applications
The device is ideal for mono-, multi-, and full-color LED
displays, LED signboards, and display backlights.
2 SDI
32 LD
29 PD
Control
Greyscale
0 Register 11
12-Bit Greyscale
PWM Control
6-Bit Dot
Correction
Constant Current
Driver
4
Delay
x0
OUT0
Max OUTn
Current
V
REF
=
1.24V
Greyscale
Counter
Control
Input
Shift
Register
0
Dot Correction
Register 5
Open&Short LED Detection
Control
Greyscale
12 Register 23
6
Dot Correction
Register 11
12-Bit Greyscale
PWM Control
6-Bit Dot
Correction
Constant Current
Driver
5
Delay
x1
OUT1
.
.
.
Constant Current
Driver
21
Delay
x15
OUT15
.
Thermal
Flag
Open
LED
Detect
Open&Short LED Detection
Control
12-Bit Greyscale
PWM Control
6-Bit Dot
Correction
23
27
V
CC
.
.
Input
Shift
Register
Greyscale
180 Register191
Dot Correction
90 Register 95
22
XERR
30
GND
Open&Short LED Detection
AS1112
SDO
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Revision 1.06
1 - 18
AS1112
Datasheet - P i n o u t
4 Pinout
Pin Assignments
Figure 2. Pin Assignments (Top View)
XTEST 25
TEST 25
GND 30
GND 30
OEN 31
OEN 31
I
REF
26
I
REF
26
V
CC
27
V
CC
27
N/C 29
N/C 28
N/C 28
PD 29
LD 32
LD 32
CLK
SDI
MODE
OUT0
OUT1
OUT2
OUT3
OUT4
1
2
3
4
5
6
7
8
10 OUT6
12 N/C
13 N/C
14 OUT8
11 OUT7
9
OUT5
24 GSCLK
23 SDO
22 XERR
21 OUT15
20 OUT14
19 OUT13
33
15 OUT9
16 OUT10
18 OUT12
17 OUT11
CLK
SDI
MODE
OUT0
OUT1
OUT2
OUT3
OUT4
1
2
3
4
5
6
7
8
10 OUT6
12 N/C
13 N/C
14 OUT8
11 OUT7
9
33
15 OUT9
16 OUT10
24 GSCLK
23 SDO
22 XERR
21 OUT15
20 OUT14
19 OUT13
18 OUT12
17 OUT11
AS1112
Thermal
Pad
AS1112B
Thermal
Pad
OUT5
Pin Descriptions
Table 2. Pin Descriptions
Pin Number
1
2
3
4:11
14:21
22
23
24
25
26
27
12,13,28
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
MODE = V
CC
: Selects dot correction mode
(see Setting Dot Correction on page 11).
OUT0:OUT7
Constant-Current Outputs 0:7
OUT8:OUT15
Constant-Current Outputs 8:15
Error Output
0 = LED open detection or overtemperature condition is detected.
XERR
1 = Normal operation.
Serial Data Output
SDO
Greyscale Clock.
Reference clock for greyscale PWM control
GSCLK
Test Pin
This pin must be connected to GND (AS1112) to ensure normal operation.
TEST
Test Pin
This pin must be connected to V
CC
(AS1112B) to ensure normal operation.
XTEST
Reference Current Terminal
I
REF
Power Supply Voltage
V
CC
This pin must not be connected.
N/C
Power Down
input with internal pulldown (AS1112)
0 = normal operation mode
PD
1 = powerdown mode
Not Connected
(AS1112B)
N/C
Ground
GND
Blank Outputs
0 = OUTn outputs are controlled by the greyscale PWM control.
OEN
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.
LD
For LD (MODE = V
CC
), the dot correction register receives new data.
Thermal Pad
Thermal Pad.
This pin must be connected to GND to ensure normal operation.
Revision 1.06
2 - 18
Pin Name
CLK
SDI
Description
29
30
31
32
33
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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 Oper-
ating 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
Parameter
Input Voltage Range to GND
Output Current (DC)
Input Voltage Range
Output Voltage Range
V
SDO
, V
XERR
to GND
Output Voltage Range
V
OUT0
: V
OUT15
to GND
ESD Rating
Storage Temperature Range
Operating Ambient
Temperature Range
32-pin TQFN 5x5 mm Package
Thermal Impedance
-55
-40
-0.3
-0.3
-0.3
Min
0.3
Max
6
90
V
CC
+
0.3
V
CC
+
0.3
15
2
+150
+85
23
Units
V
mA
V
V
V
kV
ºC
ºC
ºC/W
on 4-Layer PCB
The reflow peak soldering temperature (body
temperature) specified is in accordance with
IPC/JEDEC J-STD-020D “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).
JEDEC 22-A114 Human Body Model
Comments
Package Body Temperature
+260
ºC
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Revision 1.06
3 - 18
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
Symbol
V
CC
V
OUT
V
IH
V
IL
I
OH
I
OL
I
COC
Parameter
Supply Voltage
Voltage Applied to Output
(OUT0:OUT15)
High-Level Input Voltage
Low-Level Input Voltage
High-Level Output Current
Low-Level Output Current
Constant Output Current
V
CC
= 5 V at SDO
V
CC
= 5 V at SDO, XERR
OUT0:OUT15
0.8 x
V
CC
GND
-1.0
1.0
80
Conditions
Min
3
Typ
Max
5.5
15
V
CC
0.2 x
V
CC
Unit
V
V
V
V
mA
mA
mA
Table 5. AC Characteristics –
V
CC
= 3 V to 5.5 V, T
AMB
= -40 to 85°C (unless otherwise noted)
Symbol
f
CLK
f
GSCLK
t
WH0
/t
WL0
t
WH1
/t
WL1
t
WH2
t
WH3
t
SU0
t
SU1
t
SU2
t
SU3
t
SU4
t
H0
t
H1
t
H2
t
H3
t
H4
1. See
Figure 10 on page 12.
2. See
Figure 14 on page 14.
3. See
Figure 12 on page 13.
4. See
Figure 7 on page 8.
Hold Time
Setup Time
Parameter
Data Shift Clock Frequency
Greyscale Clock Frequency
CLK Pulse Duration
GSCLK Pulse Duration
LD Pulse Duration
OEN Pulse Duration
Conditions
CLK
GSCLK
CLK = 1/0
1
2
Min
Typ
Max
30
30
Unit
MHz
MHz
ns
ns
ns
ns
16
16
20
GSCLK = 1/0
LD = 1
1
2
3
3
OEN = 1
SDI, CLK
CLK, LD
20
12
12
4
MODE, CLK
MODE, LD
12
12
ns
4
2
OEN, GSCLK
CLK, SDI
LD, CLK
3
1
12
12
12
CLK, MODE
LD, MODE
4
12
12
ns
4
2
OEN, GSCLK
12
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Revision 1.06
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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
V
CC
= +3.0 to +5.5V, T
AMB
= -40 to +85ºC. Typical values are at T
AMB
= 25°C, V
CC
= 5V (unless otherwise specified).
Table 6. Electrical Characteristics
Symbol
V
OH
V
OL
Parameter
High-Level Output Voltage
Low-Level Output Voltage
Condition
I
OH
= -1mA, SDO
I
OL
= 1mA, SDO, XERR
V
IN
= V
CC
or GND; Pins OEN, TEST,
GSCLK, CLK, SDI, LD
I
Input Current
V
IN
= V
CC
; pin MODE, PD
V
IN
= GND; pin MODE, PD
All outputs off, R
IREF
= 10kΩ
I
CC
Supply Current
All outputs off, R
IREF
= 1.3kΩ
All outputs on, R
IREF
= 1.3kΩ
All outputs on, R
IREF
= 640Ω
I
PD
I
COC
I
LEAK
Power Down Current
Constant Output Current
Leakage Output Current
All outputs on, V
OUT
= 2V,
R
IREF
= 640Ω
All outputs off, V
OUT
= 15V,
R
IREF
= 640Ω, OUT0:OUT15
V
OUT
= 2V, R
IREF
= 640Ω,
OUT0:OUT15
V
OUT
= 2V, R
IREF
= 480Ω,
OUT0:OUT15
ΔI
COC
Constant Current Error
Device to device, average current
from OUT0:OUT15, R
IREF
= 1920Ω
(20 mA)
Device to device, average current
from OUT0:OUT15,
R
IREF
= 480Ω (80 mA)
ΔI
LNR
V
OUT
= 2V, R
IREF
= 640Ω
OUT0:OUT15
V
OUT
= 2V, R
IREF
= 480Ω
OUT0:OUT15
V
OUT
= 2 to 4V, R
IREF
= 640Ω,
OUT0:OUT15
V
OUT
= 2 to 4V, R
IREF
= 480Ω,
OUT0:OUT15
Junction temperature
Junction temperature
V
CC
= 5V
1
1
Min
V
CC
-
0.5
Typ
Max
Unit
V
0.5
-1
1
100
-1
1.2
4
15
30
40
54
61
20
±3
±3
±3
±4.5
±4.5
±4.5
69
1
3
10
20
40
V
µA
mA
nA
mA
nA
%
±3
±1
±1
±0.1
±0.1
150
125
3.6
0.3
±4.5
±2.5
%/V
±2.5
±0.5
%/V
±0.5
ºC
ºC
V
0.4
1.28
V
V
Line Regulation
ΔI
LDR
Load Regulation
T
TEF
T
TWF
V
LSD
V
LOD
V
IREF
Thermal Error Flag Threshold
Thermal Warn Flag Threshold
LED Short Detection
Threshold
LED Open Detection
Threshold
Reference Voltage Output
R
IREF
= 640Ω
1.20
1.24
1. Specified by design. Not tested.
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