ST2221C
Version
: A.004
Issue Date : 2002/06/14
File Name : SP-ST2221C-A.004.doc
Total Pages : 17
16-Bit Constant Current LED Drivers
新竹市科學園區展業一路 9 號 7 樓之 1
SILICON TOUCH TECHNOLOGY INC.
9-7F-1, Prosperity Road I, Science Based Industrial Park,
Hsin-Chu, Taiwan 300, R.O.C.
Tel：886-3-5645656
Fax：886-3-5645626
點晶科技股份有限公司
ST2221C
SILICON TOUCH TECHNOLOGY INC.
ST2221C
16-Bit Constant Current LED Drivers
General Description
The ST2221C is specifically designed for LED and LED DISPLAY constant current drivers.
The value of constant current can be varied using an external resistor (Iout = 5 ~90mA). The
devices include a 16-bit shift registers, latches, and constant current drivers on a single Silicon
CMOS chip.
Features
z
z
z
z
z
Constant Current Output :
Current with one resistor for 5mA to 90mA
Maximum Clock Frequency : 25MHz (Cascade Operation)
5V CMOS Compatible Input
Package :
DIP24 , SOP24, SSOP24
Constant Current Matching: (Ta = 25°C、VDD = 5.0V)
Bit-to-Bit: ± 6.0%、Chip-to-Chip : ± 10.0%、
@ IOUT = 5 ~ 90mA
16-Bit Constant Current LED Drivers
- 1 -
Version：A.004
點晶科技股份有限公司
ST2221C
SILICON TOUCH TECHNOLOGY INC.
Pin Connection (Top view)
GND
SERIAL-IN
1
2
24
VDD
23
R-EXT
CLOCK
LATCH
OUT0
3
4
22
21
SERIAL-OUT
5
OUT1
6
OUT2
OUT3
7
8
20
19
18
OUT4
9
OUT5
OUT6
10
11
12
OUT7
ENABLE
OUT15
OUT14
OUT13
17
16
OUT12
OUT11
15
14
OUT10
13
OUT8
OUT9
Block Diagram
R-EXT
OUT15
OUT1
OUT0
I-REG.
ENABLE
Q
Q
ST D
ST D
Q
ST D
LATCH
SERIAL-IN
D
CK
Q
D
Q
CK
D
CK
Q
D
Q
SERIAL-OUT
CK
CLOCK
16-Bit Constant Current LED Drivers
- 2 -
Version：A.004
點晶科技股份有限公司
ST2221C
SILICON TOUCH TECHNOLOGY INC.
Timing Diagram
1
2
3
15
16
5V
CLOCK
0V
5V
SERIAL-IN
0V
5V
LATCH
0V
5V
ENABLE
0V
On
Off
OUT0
On
OUT1
Off
On
OUT2
Off
OUT15
On
Off
SERIAL-OUT
5V
0V
(Note) Latches are level sensitive (not edge triggered).
LATCH-terminal = H level, latches become transparent; LATCH-terminal = L level, latches hold data.
ENABLE-terminal = H level, all outputs (OUT0~15) are off.
An external resistor is connected between R-EXT and GND for setting up the value of constant current.
SERIAL-OUT changes state on the falling edges of clock.
Pin Description
PIN No.
1
2
3
4
5~20
21
22
23
24
PIN NAME
GND
SERIAL-IN
CLOCK
LATCH
OUT0~15
ENABLE
SERIAL-OUT
R-EXT
VDD
FUNCTION
Ground terminal
Input terminal of a data shift register
Input terminal of a clock for shift register
Input terminal of data strobe
Output terminals
Input terminal of output enable (active low)
Output terminal of a data shift register
Input terminal of an external resistor
5V Supply voltage terminal
16-Bit Constant Current LED Drivers
- 3 -
Version：A.004
點晶科技股份有限公司
ST2221C
SILICON TOUCH TECHNOLOGY INC.
Equivalent Circuit of Inputs and Outputs
1. ENABLE terminal
VDD
2. LATCH terminal
VDD
RIN(up)
ENABLE
LATCH
RIN(DOWN)
GND
3. CLOCK, SERIAL-IN terminal
VDD
CLOCK,
GND
4. SERIAL-OUT terminal
VDD
15th LATCH DATA
SERIAL-OUT
SERIAL-IN
GND
16-Bit Constant Current LED Drivers
GND
- 4 -
Version：A.004
點晶科技股份有限公司
ST2221C
SILICON TOUCH TECHNOLOGY INC.
Maximum Ratings (Ta = 25°C, Tj(max) = 140°C)
CHARACTERISTIC
SYMBOL
RATING
UNIT
VDD
VIN
IOUT
VOUT
fCLK
IGND
0 ~ 7.0
-0.4 ~ VDD+0.4
90
-0.5 ~ 9.5
25
1440
2.87 (DIP-24 : Ta=25°C)
1.45 (SOP-24 : Ta=25°C)
1.27 (SSOP-24 : Ta=25°C)
40.0 (DIP-24)
79.2 (SOP-24)
90.2 (SSOP-24)
-55 ~ 150
V
V
mA
V
MHz
mA
Supply Voltage
Input Voltage
Output Current
Output Voltage
Clock Frequency
GND Terminal Current
Power Dissipation
PD
Thermal Resistance
Rth(j-a)
Storage Temperature
Tstg
W
°C/W
°C
Recommended Operating Condition
CHARACTERISTIC
Supply Voltage
Output Voltage
Operating temperature
Output Current
Input Voltage
LATCH Pulse Width
CLOCK Pulse Width
Set-up Time for DATA
Hold Time for DATA
Set-up Time for LATCH
Clock Frequency
Power Dissipation
SYMBOL
VDD
VOUT
TOPR
IO
IOH
IOL
VIH
VIL
tw LAT
tw CLK
tsetup(D)
thold(D)
tsetup(L)
fCLK
PD
CONDITION
⎯
⎯
⎯
OUTn
SERIAL-OUT
SERIAL-OUT
MIN.
4.5
TYP.
5.0
⎯
⎯
⎯
⎯
⎯
⎯
⎯
⎯
⎯
⎯
⎯
⎯
⎯
⎯
⎯
-40
5
⎯
⎯
⎯
⎯
0.7VDD
-0.3
VDD = 4.5 ~ 5.5 V
15
15
20
20
15
Cascade operation
Ta = 85°C (DIP-24)
Ta = 85°C (SOP-24)
Ta = 85°C (SSOP-24)
16-Bit Constant Current LED Drivers
⎯
⎯
⎯
- 5 -
⎯
MAX.
5.5
9
85
85
1.0
-1.0
VDD+0.3
0.3VDD
⎯
⎯
⎯
⎯
⎯
25
UNIT
V
V
℃
mA
V
ns
ns
ns
ns
ns
MHz
1.37
0.69
0.61
W
Version：A.004
點晶科技股份有限公司
ST2221C
SILICON TOUCH TECHNOLOGY INC.
Electrical Characteristics (VDD = 5.0 V, Ta = 25°C unless otherwise noted)
CHARACTERISTIC
SYMBOL
CONDITION
MIN.
TYP.
MAX.
Input Voltage “H” Level
VIH
⎯
0.7VDD
⎯
VDD
Input Voltage “L” Level
VIL
⎯
GND
⎯
0.3VDD
Output Leakage Current
IOH
VOH = 9.5 V
⎯
⎯
1.0
VOL
IOL = 1.0 mA
⎯
⎯
0.4
VOH
IOH = -1.0 mA
4.6
⎯
⎯
VOUT = 0.7±0.25V
⎯
3
6
⎯
3
6
Output Voltage ( S - OUT)
IOL1
REXT = 910Ω
Output Current (Bit-Bit)
VOUT = 0.7±0.25V
IOL2
REXT = 360Ω
UNIT
V
uA
V
%
IOL3
VOUT = 0.7V REXT = 910Ω
⎯
5
10
IOL4
VOUT = 0.7V REXT = 360Ω
⎯
5
10
Supply Voltage Regulation
% / VDD REXT = 470Ω, Ta = -40 ~ 85°C
⎯
1.5
5.0
%/V
Pull-Up Resistor
RIN(up)
⎯
150
300
600
KΩ
RIN(down)
⎯
KΩ
Output Current (Chip-Chip)
Pull-Down Resistor
Supply Current “OFF”
Supply Current “ON”
100
200
400
IDD(off)1 REXT = OPEN, OUT0~7 = off
⎯
0.3
0.6
IDD(0ff)2 REXT = 470Ω, OUT0~7 = off
3.9
5.5
7.7
IDD(off)3 REXT = 250Ω, OUT0~7 = off
7.2
10.1
14.1
IDD(on)1 REXT = 470Ω, OUT0~7 = on
3.9
5.5
7.7
IDD(on)2 REXT = 250Ω, OUT0~7 = on
7.2
10.1
14.1
mA
Switching Characteristics (Ta = 25 °C unless otherwise noted)
CHARACTERISTIC
SYMBOL
SIN-OUTn
Propagation LATCH-OUTn
Delay Time
(“L” to “H”) ENABLE-OUTn
CLK-SOUT
SIN-OUTn
Propagation LATCH-OUTn
Delay Time
(“H” to “L”) ENABLE-OUTn
CLK-SOUT
Output Current Rise Time
Output Current Fall Time
1
tpLH
CONDITION
VDD=5.0V
VIH=VDD
VIL=GND
REXT=470Ω1
VL=3.0V
RL=65Ω
CL=13pF
tpHL
tor
tof
MIN.
TYP.
MAX.
⎯
450
550
UNIT
⎯
450
550
⎯
450
550
⎯
15
20
⎯
20
40
⎯
20
40
⎯
20
40
⎯
15
20
⎯
450
550
ns
⎯
20
40
ns
ns
ns
Delay time tpLH and Rise Time tor will both increase as the Rext value increased.
16-Bit Constant Current LED Drivers
- 6 -
Version：A.004
點晶科技股份有限公司
ST2221C
SILICON TOUCH TECHNOLOGY INC.
Test Circuit
DC characteristic
IDD
VDD
OUT0
ENABLE
IOL
CLOCK
IIL ,IIH
LATCH
VIL ,VIH
OUT15
SERIAL-IN
R-EXT GND
SERIAL-OUT
I ref
AC characteristic
RL
VDD
VIL ,VIH
OUT0
ENABLE
CL
SW-
CLOCK
MATRIX
LATCH
RL
OUT15
SERIAL-IN
R-EXT GND
SERIAL-OUT
CL
CL
16-Bit Constant Current LED Drivers
- 7 -
VL
Version：A.004
點晶科技股份有限公司
ST2221C
SILICON TOUCH TECHNOLOGY INC.
Timing Diagram
1. CLOCK-SERIAL-IN, SERIAL-OUT, OUTn
tr
tf
twCLK
CLOCK
SERIAL-IN
90%
50%
10%
tsetup
90%
50%
10%
twCLK
50%
50%
thold
50%
50%
tof
tor
90%
50%
10%
OUTn (current)
90%
50%
10%
tpLH
tpHL
50%
50%
SERIAL-OUT
tpHL
tpLH
2. CLOCK-LATCH
50%
CLOCK
SERIAL-IN
“L” level = DATA HOLD
thold(L)
LATCH
50%
50%
tsetup(L)
3. ENABLE-OUTn
ENABLE
50%
50%
tpHL
tpLH
50%
50%
OUTn
16-Bit Constant Current LED Drivers
- 8 -
Version：A.004
點晶科技股份有限公司
ST2221C
SILICON TOUCH TECHNOLOGY INC.
Iout-Duty Cycle (DIP)
Vo=0.45(V)
Vo=0.70(V)
Vo=0.95(V)
Iout (mA/bit)
Iout (mA/bit)
Iout-Duty Cycle (DIP)
90
80
70
60
50
40
30
20
10
0
Vdd=5V
Tj=140°C (Max)
16bit Active
Ta=25°C
0
20
40
60
80
90
80
70
60
50
40
30
20
10
0
Vo=0.45(V)
Vo=0.70(V)
Vo=0.95(V)
Vdd=5V
Tj=140°C (Max)
16bit Active
Ta=60°C
0
100
20
40
Iout (mA/bit)
Iout (mA/bit)
Vo=0.45(V)
Vo=0.70(V)
Vo=0.95(V)
Vdd=5V
Tj=140°C (Max)
16bit Active
Ta=85°C
20
40
60
80
90
80
70
60
50
40
30
20
10
0
100
Vo=0.45(V)
Vo=0.70(V)
Vo=0.95(V)
Vdd=5V
Tj=140°C (Max)
16bit Active
Ta=25°C
0
20
Duty Cycle (%)
Iout (mA/bit)
Iout (mA/bit)
Vo=0.95(V)
Vdd=5V
Tj=140°C (Max)
16bit Active
Ta=60°C
20
40
60
60
80
100
Iout - Duty Cycle (SOP)
Vo=0.45(V)
Vo=0.70(V)
0
40
Duty Cycle (%)
Iout-Duty Cycle (SOP)
90
80
70
60
50
40
30
20
10
0
100
Iout-Duty Cycle (SOP)
Iout - Duty Cycle (DIP)
0
80
Duty Cycle (%)
Duty Cycle (%)
90
80
70
60
50
40
30
20
10
0
60
80
90
80
70
60
50
40
30
20
10
0
100
Vo=0.95(V)
Vdd=5V
Tj=140°C (Max)
16bit Active
Ta=85°C
0
Duty Cycle (%)
16-Bit Constant Current LED Drivers
Vo=0.45(V)
Vo=0.70(V)
20
40
60
80
100
Duty Cycle (%)
- 9 -
Version：A.004
點晶科技股份有限公司
ST2221C
SILICON TOUCH TECHNOLOGY INC.
Iout - Duty Cycle (SSOP)
Vo=0.45(V)
Vo=0.70(V)
Vo=0.95(V)
Iout (mA/bit)
Iout (mA/bit)
Iout-Duty Cycle (SSOP)
90
80
70
60
50
40
30
20
10
0
Vdd=5V
Tj=140°C (Max)
16bit Active
Ta=25°C
0
20
40
60
80
90
80
70
60
50
40
30
20
10
0
100
Vo=0.45(V)
Vo=0.7(V)
Vo=0.95(V)
Vdd=5V
Tj=140°C (Max)
16bit Active
Ta=60°C
0
Duty Cycle (%)
60
80
100
Iout-Rext
100
Iout={ Vref(V)/Rext(ohm) }*13.79
90
Vo=0.45(V)
80
70
Vo=0.7(V)
Vo=0.7(V)
Iout (mA)
Iout (mA/bit)
40
Duty Cycle (%)
Iout - Duty Cycle (SSOP)
90
80
70
60
50
40
30
20
10
0
20
Vo=0.95(V)
60
50
40
30
20
Vdd=5V
Tj=140°C (Max)
16bit Active
Ta=85°C
10
0
0
20
40
60
80
100
100
Duty Cycle (%)
16-Bit Constant Current LED Drivers
1000
10000
Rext (Ω)
- 10 -
Version：A.004
點晶科技股份有限公司
ST2221C
SILICON TOUCH TECHNOLOGY INC.
3.2
2.8
2.4
2
1.6
1.2
0.8
0.4
0
Imax - Ta (DIP)
DIP
Iout max (mA/bit)
Power dissipation Pd (W)
Ta - Pd
SOP
SSOP
0
50
100
150
90
80
70
60
50
40
30
20
10
0
Vo=0.7(V)
Vo=1.0(V)
Vdd=5V
Tj=140°C (Max)
16bit Active
Rext=470ohm
0
Ambient Temperature Ta
50
100
150
Ambient Temperature Ta
90
80
70
60
50
40
30
20
10
0
Imax - Ta (SOP)
Vo=0.7(V)
Iout max (mA/bit)
Iout max (mA/bit)
Imax - Ta (SOP)
Vo=1.0(V)
Vdd=5V
Tj=140°C (Max)
16bit Active
Rext=470ohm
0
50
100
90
80
70
60
50
40
30
20
10
0
150
Vo=0.7(V)
Vo=1.0(V)
Vdd=5V
Tj=140°C (Max)
16bit Active
Rext=470ohm
0
Ambient Temperature Ta
50
100
150
Ambient Temperature Ta
Note
As the power dissipation of a semiconductor chip is limited its package and ambient
temperature, this device requires a maximum output current be calculated for a given operating
condition. The maximum allowable power consumption (Pd (max)) of this device is
calculated as follows:
(Tj (junction temperature) (max) - Ta (ambient temperature) )(°C )
Pd (max)(Watt ) =
Rth (°C / Watt )
Based on the Pd (max), the maximum allowable current can be calculated as follows:
Iout = ( Pd – VDD‧IDD) / ( # outputs‧Vo‧Duty )
16-Bit Constant Current LED Drivers
- 11 -
Version：A.004
點晶科技股份有限公司
ST2221C
SILICON TOUCH TECHNOLOGY INC.
System Configuration Example
[1] Output current (IOUT)
Sink current is set by the external resistor as shown in the figure (Iout vs. Rext).
[2] LED supply voltage (VLED) setup
VLED = VCE ( Tr Vsat ) + Vf ( LED forward voltage ) + VO ( IC supply voltage)
To prevent too much power dissipated by the device due to higher VLED , an additional R
can be used to reduce the Vout when the outputs consume current:
R=
VLED − VCE − V f − VO (min)
I O (max) * Bit (max)
VLED = 3~4 (V)
＋
Vf
—
SCAN
OUT0
ENABLE
＋
VCE
—
Vo
CLOCK
LATCH
SERIAL-IN
R-EXT GND
OUT15
R
SERIAL-OUT
CPU
OUT0
ENABLE
CLOCK
LATCH
SERIAL-IN
R-EXT GND
OUT15
SERIAL-OUT
Note
This device has only one ground pin shared by signal, output sink current, and power ground. It is
advisable to pattern the ground layout with minimized inductance such that the switching noise induced
by the input signals and the output sink current would not cause chip malfunction. To prevent the
drivers’ outputs from damage by overshoot stress, it is also advisable not to turn off the drivers and
scan transistors simultaneously.
16-Bit Constant Current LED Drivers
- 12 -
Version：A.004
點晶科技股份有限公司
ST2221C
SILICON TOUCH TECHNOLOGY INC.
Package Outline
P-DIP 24
UNIT：INCH
1.250 ± 0.03
0.355 ± 0.02
0.300
0.258 ± 0.005
θ=7 ~15
0.130 ± 0.05
0.130 ± 0.02
SEATING PLANE
0.210
0.100typ
0.018typ
0.060typ
16-Bit Constant Current LED Drivers
- 13 -
Version：A.004
點晶科技股份有限公司
ST2221C
SILICON TOUCH TECHNOLOGY INC.
Package Outline
SOP24
0.020*45°
0.406 ± 0.013
0.295 ± 0.004
UNIT：INCH
0.016typ
0.050typ
0.600 ± 0.014
16-Bit Constant Current LED Drivers
- 14 -
0.010
0.099± 0.006
0.012max
0.004max
0.035±0.015
θ=0~8
Version：A.004
點晶科技股份有限公司
ST2221C
SILICON TOUCH TECHNOLOGY INC.
Package Outline
SSOP24
0.020*45°
0.236 ± 0.008
0.154 ± 0.004
UNIT：INCH
0.012typ
0.025typ
0.341 ± 0.004
0.004max
16-Bit Constant Current LED Drivers
0.01max
- 15 -
0.010
0.064± 0.011
0.025±0.025
θ=0~8
Version：A.004
點晶科技股份有限公司
ST2221C
SILICON TOUCH TECHNOLOGY INC.
The products listed herein are designed for ordinary electronic applications, such as
electrical appliances, audio-visual equipment, communications devices and so on. Hence,
it is advisable that the devices should not be used in medical instruments, surgical
implants, aerospace machinery, nuclear power control systems, disaster/crime-prevention
equipment and the like. Misusing those products may directly or indirectly endanger
human life, or cause injury and property loss.
Silicon Touch Technology, Inc. will not take any responsibilities regarding the misusage
of the products mentioned above. Anyone who purchases any products described herein
with the above-mentioned intention or with such misused applications should accept full
responsibility and indemnify. Silicon Touch Technology, Inc. and its distributors and all
their officers and employees shall defend jointly and severally against any and all claims
and litigation and all damages, cost and expenses associated with such intention and
manipulation.
16-Bit Constant Current LED Drivers
- 16 -
Version：A.004