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ST2221C
Version : 1.01 Issue Date : 2000/10/13 File Name : ST2221C_1.01.doc Total Pages : 17
16-Bit Constant Current LED Drivers
ST2221C
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 ~120mA). The devices include a 16-bit shift registers, latches, and constant current drivers on a single Silicon CMOS chip.
Features
n n n n n
Constant Current Output : Maximum Clock Frequency : 5V CMOS Compatible Input Package : Constant Current Matching:
Current with one resistor for 5mA to 120mA 25MHz (Cascade Operation) DIP24 , SOP24, SSOP24 (Ta = 25CVDD = 5.0V) Bit-to-Bit: 6.0%Chip-to-Chip : 10.0% @ IOUT = 5 ~ 40mA Bit-to-Bit: 6.0%Chip-to-Chip : 10.0% @ IOUT = 40 ~ 120mA
16-Bit Constant Current LED Drivers
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Version1.01
ST2221C Pin Connection (Top view)
GND SERIAL-IN CLOCK LATCH OUT0 OUT1 OUT2 OUT3 OUT4 OUT5 OUT6 OUT7
1 2 3 4 5 6 7 8 9 10 11 12
24 23 22 21 20 19 18 17 16 15 14 13
VDD R-EXT SERIAL-OUT ENABLE OUT15 OUT14 OUT13 OUT12 OUT11 OUT10 OUT9 OUT8
Block Diagram
OUT0 R-EXT
I-REG.
OUT1
OUT15
ENABLE
Q ST D Q ST D Q ST D
LATCH SERIAL-IN CLOCK
D CK Q D CK Q D CK Q D CK Q
SERIAL-OUT
16-Bit Constant Current LED Drivers
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ST2221C Timing Diagram
1 2 3 15 16 5V 0V 5V 0V 5V 0V 5V 0V On Off On Off On Off On Off 5V 0V
CLOCK SERIAL-IN LATCH ENABLE OUT0 OUT1 OUT2 OUT15 SERIAL-OUT
(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
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Version1.01
ST2221C Equivalent Circuit of Inputs and Outputs
1. ENABLE terminal
VDD
RIN(up)
2. LATCH terminal
VDD
ENABLE
LATCH
RIN(DOWN)
GND
GND
3. CLOCK, SERIAL-IN terminal
VDD
4. SERIAL-OUT terminal
VDD
CLOCK, SERIAL-IN
15th LATCH DATA
SERIAL-OUT
GND
GND
16-Bit Constant Current LED Drivers
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ST2221C Maximum Ratings (Ta = 25C, Tj(max) = 140C)
CHARACTERISTIC Supply Voltage Input Voltage Output Current Output Voltage Clock Frequency GND Terminal Current Power Dissipation SYMBOL VDD VIN IOUT VOUT fCLK IGND PD RATING 0 ~ 7.0 -0.4 ~ VDD+0.4 120 -0.5 ~ 9.5 25 1920 2.87 (DIP-24 : Ta=25C) 1.45 (SOP-24 : Ta=25C) 1.27 (SSOP-24 : Ta=25C) 40.0 (DIP-24) 79.2 (SOP-24) 90.2 (SSOP-24) -55 ~ 150 UNIT V V mA V MHz mA W
Thermal Resistance Storage Temperature
Rth(j-a) Tstg
C/W C
Recommended Operating Condition
CHARACTERISTIC Supply Voltage Output Voltage Output Current SYMBOL VDD VOUT IO IOH IOL VIH VIL tw LAT tw CLK tsetup(D) thold(D) tsetup(L) fCLK PD CONDITION
3/4 3/4
OUTn SERIAL-OUT SERIAL-OUT
MIN. 4.5
TYP. 5.0
3/4
5
3/4 3/4
0.7VDD -0.3 15 15 20 20 15
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
3/4 3/4
VDD = 4.5 ~ 5.5 V
Cascade operation Ta = 85C (DIP-24) Ta = 85C (SOP-24) Ta = 85C (SSOP-24)
3/4 3/4 3/4
3/4 3/4 3/4 3/4 3/4 3/4 3/4 3/4 3/4 3/4 3/4 3/4 3/4 3/4
MAX. 5.5 9 115 1.0 -1.0 VDD+0.3 0.3VDD
UNIT V V mA
V ns ns ns ns ns MHz W
3/4 3/4 3/4 3/4 3/4
25
1.37
0.69 0.61
16-Bit Constant Current LED Drivers
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ST2221C Electrical Characteristics (VDD = 5.0 V, Ta = 25C unless otherwise noted)
CHARACTERISTIC Input Voltage "H" Level Input Voltage "L" Level Output Leakage Current Output Voltage ( S - OUT) SYMBOL VIH VIL IOH VOL VOH IOL1 Output Current (Bit-Bit) IOL2 Output Current (Chip-Chip) Supply Voltage Regulation Pull-Up Resistor Pull-Down Resistor Supply Current "OFF" IOL3 IOL4 RIN(up) RIN(down) VOH = 9.5 V IOL = 1.0 mA IOH = -1.0 mA VOUT = 0.70.25V REXT = 910W VOUT = 0.70.25V REXT = 360W VOUT = 0.7V VOUT = 0.7V REXT = 910W REXT = 360W 3/4 3/4 CONDITION 3/4 3/4 MIN. 0.7VDD GND 3/4 3/4 4.6 3/4 3/4 3/4 3/4 3/4 150 100 3/4 3.9 7.2 3.9 7.2 TYP. 3/4 3/4 3/4 3/4 3/4 3 3 5 5 1.5 300 200 0.3 5.5 10.1 5.5 10.1 MAX. UNIT VDD 0.3VDD 1.0 0.4 3/4 6 6 10 10 5.0 600 400 0.6 7.7 14.1 7.7 14.1 mA %/V KW KW % V uA V
% / VDD REXT = 470W, Ta = -40 ~ 85C
IDD(off)1 REXT = OPEN, OUT0~7 = off IDD(0ff)2 REXT = 470W, OUT0~7 = off IDD(off)3 REXT = 250W, OUT0~7 = off Supply Current "ON" IDD(on)1 REXT = 470W, OUT0~7 = on IDD(on)2 REXT = 250W, OUT0~7 = on
Switching Characteristics (Ta = 25 C unless otherwise noted)
CHARACTERISTIC 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 SYMBOL CONDITION VDD=5.0V VIH=VDD VIL=GND REXT=470W 1 VL=3.0V RL=65W CL=13pF MIN. 3/4 3/4 3/4 3/4 3/4 3/4 3/4 3/4 3/4 3/4 TYP. 150 150 150 15 30 30 30 15 170 20 MAX. 300 300 300 20 60 60 60 20 340 40 ns ns ns ns UNIT
tpLH
tpHL tor tof
1
Delay time tpLH and Rise Time tor will both increase as the Rext value increased. -6Version1.01
16-Bit Constant Current LED Drivers
ST2221C Test Circuit
DC characteristic
IDD
VDD ENABLE IIL ,IIH CLOCK LATCH VIL ,VIH SERIAL-IN R-EXT GND
OUT0 IOL
OUT15 SERIAL-OUT
I ref
AC characteristic
VIL ,VIH ENABLE SWMATRIX CLOCK LATCH SERIAL-IN
VDD
RL OUT0 CL RL OUT15 SERIAL-OUT CL
R-EXT GND
CL
VL
16-Bit Constant Current LED Drivers
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Version1.01
ST2221C Timing Diagram
1. CLOCK-SERIAL-IN, SERIAL-OUT, OUTn
tr twCLK
90% 50% 90% 50% 10%
tf
twCLK
50% 50%
CLOCK
10%
tsetup
thold
50%
SERIAL-IN
50%
tor OUTn (current) tpLH
50% 90% 50% 10%
tof
90% 50% 10%
tpHL
50%
SERIAL-OUT tpLH tpHL
2. CLOCK-LATCH
50%
CLOCK
SERIAL-IN
"L" level = DATA HOLD thold(L) LATCH tsetup(L)
50% 50%
3. ENABLE-OUTn
ENABLE
50% 50%
tpLH
tpHL
50%
50%
OUTn
16-Bit Constant Current LED Drivers
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ST2221C
Iout-Duty Cycle (DIP) 130 120 110 100 90 80 70 60 50 40 30 20 10 0 0 130 120 110 100 90 80 70 60 50 40 30 20 10 0 0
Iout-Duty Cycle (DIP)
Iout (mA/bit)
Iout (mA/bit)
Vo=0.45(V) Vo=0.70(V) Vo=0.95(V)
Vo=0.45(V) Vo=0.70(V) Vo=0.95(V)
Vdd=5V Tj=140C (Max) 16bit Active Ta=25C
Vdd=5V Tj=140C (Max) 16bit Active Ta=60C
20
40
60
80
100
20
40
60
80
100
Duty Cycle (%)
Duty Cycle (%)
Iout - Duty Cycle (DIP) 130 120 110 100 90 80 70 60 50 40 30 20 10 0 0
Vo=0.45(V) Vo=0.70(V)
Iout-Duty Cycle (SOP) 130 120 110 100 90 80 70 60 50 40 30 20 10 0 0
Vo=0.45(V) Vo=0.70(V)
Vo=0.95(V)
Vo=0.95(V)
Iout (mA/bit)
Vdd=5V Tj=140C (Max) 16bit Active Ta=85C
Iout (mA/bit)
Vdd=5V Tj=140C (Max) 16bit Active Ta=25C
20
40
60
80
100
20
40
60
80
100
Duty Cycle (%)
Duty Cycle (%)
Iout-Duty Cycle (SOP) 130 120 110 100 90 80 70 60 50 40 30 20 10 0 0 130 120 110 100 90 80 70 60 50 40 30 20 10 0 0
Iout - Duty Cycle (SOP)
Vo=0.45(V)
Vo=0.45(V)
Vo=0.70(V) Vo=0.95(V)
Iout (mA/bit)
Iout (mA/bit)
Vo=0.70(V)
Vo=0.95(V)
Vdd=5V Tj=140C (Max) 16bit Active Ta=60C
Vdd=5V Tj=140C (Max) 16bit Active Ta=85C
20
40
60
80
100
20
40
60
80
100
Duty Cycle (%)
Duty Cycle (%)
16-Bit Constant Current LED Drivers
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Version1.01
ST2221C
Iout-Duty Cycle (SSOP) 130 120 110 100 90 80 70 60 50 40 30 20 10 0 0
Iout-Duty Cycle (SSOP) 130 120 110 100 90 80 70 60 50 40 30 20 10 0 0
Vo=0.45(V) Vo=0.70(V)
Vo=0.45(V)
Iout (mA/bit)
Vo=0.95(V)
Iout (mA/bit)
Vo=0.70(V)
Vo=0.95(V)
Vdd=5V Tj=140C (Max) 16bit Active Ta=25C
Vdd=5V Tj=140C (Max) 16bit Active Ta=60C
20
40
60
80
100
20
40
60
80
100
Duty Cycle (%)
Duty Cycle (%)
Iout - Duty Cycle (SSOP) 130 120 110 100 90 80 70 60 50 40 30 20 10 0 0
130 120
Vo=0.45(V)
Iout-Rext
Iout={ Vref(V)/Rext(ohm) }*13.79
110 100
Iout (mA/bit)
Vo=0.7(V)
90 80 Iout (mA)
Vo=0.95(V)
70 60 50 40
Vo=0.7(V)
Vdd=5V Tj=140C (Max) 16bit Active Ta=85C
30 20 10
20
40
60
80
100
0 100 1000 Rext () 10000
Duty Cycle (%)
16-Bit Constant Current LED Drivers
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ST2221C
Ta - Pd 3.2 2.8 2.4 2 1.6 1.2 0.8 0.4 0 0
120 110 100 90 80 70 60 50 40 30 20 10 0 0 Imax - Ta (DIP)
Power dissipation Pd (W)
Iout max (mA/bit)
DIP
Vo=0.7(V)
Vo=1.0(V)
SOP
SSOP
Vdd=5V Tj=140C (Max) 16bit Active Rext=470ohm
50
100
150
50
100
150
Ambient Temperature Ta
Ambient Temp erature Ta
Imax - Ta (SOP) 120 110 100 90 80 70 60 50 40 30 20 10 0 0 120 110 100 90 80 70 60 50 40 30 20 10 0 0
Imax - Ta (SSOP)
Iout max (mA/bit)
Vo=0.7(V) Vo=1.0(V)
Iout max (mA/bit)
Vo=0.7(V) Vo=1.0(V)
Vdd=5V Tj=140C (Max) 16bit Active Rext=470ohm
Vdd=5V Tj=140C (Max) 16bit Active Rext=470ohm
50
100
150
50
100
150
Ambient Temp erature Ta
Ambient Temp erature 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
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Version1.01
ST2221C 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: VLED - VCE - V f - VO (min) I O (max) * Bit (max)
VLED = 3~4 (V)
R=
V
D SCAN D ENABLE CLOCK LATCH SERIAL-IN R-EXT GND OUT15 SERIAL-OUT OUT0
Vf -- Vo
VCE --
R
R
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
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Version1.01
ST2221C
Package Outline P-DIP 24
UNITINCH
1.250
0.03 =7 ~15 0.258 0.005
0.130 0.05 0.130 0.02 SEATING PLANE 0.210
0.100typ 0.018typ
0.060typ
16-Bit Constant Current LED Drivers
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0.355 0.02 Version1.01
0.300
ST2221C
Package Outline SOP24
UNITINCH
0.295 0.004 0.406 0.013
0.016typ 0.050typ
0.600 0.014 0.099 0.006
0.020*45
0.0350.015
0.010
0.004max
0.012ma
=0~8
16-Bit Constant Current LED Drivers
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x
Version1.01
ST2221C
Package Outline SSOP24
UNITINCH
0.154 0.004
0.236 0.008
0.016typ
0.025typ
0.341 0.004 0.064 0.011
0.020*45
0.0250.025
0.010
=0~8
0.004max
16-Bit Constant Current LED Drivers
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0.01max
Version1.01
ST2221C
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
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Version1.01

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