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TLC5921 LED DRIVER
SLLS390 - SEPTEMBER 1999
D D D D D D D D D D D D D D
Drive Capability and Output Counts - 80 mA (Current Sink) x 16 Bits Constant Current Output Range - 1 to 80 mA (Current Value Setting for All Output Terminals Using External Resistor) Constant Current Accuracy - 1% (Typ) - 4% (Max) (Maximum Error Between Bits, All Bits On) Voltage Applied to Constant Current Output Terminal - Minimum 0.6 V (Output Current 40 mA) - Minimum 1 V (Output Current 80 mA) Data Input - Clock Synchronized 1 Bit Serial Input Data Output - Clock Synchronized 1 bit Serial Output (With Timing Selection) Input/Output Signal Level . . . CMOS Level Power Supply Voltage . . . 4.5 V to 5.5V Maximum Output Voltage . . . 17 V (Max) Data Transfer Rate . . . 20 MHz (Max) Operating Free-Air Temperature Range -20C to 85C Available in 32 Pin HTSSOP DAP Package (PD=3.9 W, TA = 25C) LOD Function . . . LED Open Detection (Error Signal Output at LED Disconnection) TSD Function . . . Thermal Shutdown (Turn Output Off When Junction Temperature Exceeds Limit)
DAP PACKAGE (TOP VIEW)
GND BLANK XLAT SCLK SIN PGND OUT0 OUT1 PGND OUT2 OUT3 OUT4 OUT5 PGND OUT6 OUT7
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17
VCC IREF SOMODE XDOWN SOUT PGND OUT15 OUT14 PGND OUT13 OUT12 OUT11 OUT10 PGND OUT9 OUT8
description
The TLC5921 is a current-sink constant current driver incorporating shift register and data latch. The current value at constant current output can be set by one external register. The device also incorporates thermal shutdown (TSD) circuitry which turns constant current output off when the junction temperature exceeds the limit, and LED open detection (LOD) circuitry to report the LED was disconnected.
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
PRODUCTION DATA information is current as of publication date. Products conform to specifications per the terms of Texas Instruments standard warranty. Production processing does not necessarily include testing of all parameters.
Copyright (c) 1999, Texas Instruments Incorporated
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TLC5921 LED DRIVER
SLLS390 - SEPTEMBER 1999
functional block diagram
VCC SOMODE
SCLK SIN
16 bits Shift Register
Timing Selector SOUT
XLAT 100 k 100 k BLANK IREF GND PGND OUT0
16 bits Data Latch
XDOWN 16 bits Constant Current Driver and LED Disconnection detection
TSD
OUT15
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TLC5921 LED DRIVER
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equivalent input and output schematic diagrams
Input (except SCLK) VCC Input (SCLK) VCC
INPUT
INPUT
GND
GND
SOUT VCC
OUTPUT
GND XDOWN XDOWN
GND
OUTn OUTn
GND
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TLC5921 LED DRIVER
SLLS390 - SEPTEMBER 1999
Terminal Functions
TERMINAL NAME NO. 5 28 4 SIN
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I 1 bit serial data input SOUT SCLK O I 1 bit serial data output Clock input for data transfer. All the data in the shift register is shifted to MSB by 1 bit synchronizing to the rising edge of SCLK, and data at SIN is shifted to LSB at the same time. (Schmitt buffer input) XLAT 3 I Latch. When XLAT is high, data on shift register goes through latch. When XLAT is low, data is latched. Accordingly, if data on shift register is changed during XLAT high, this new value is latched (level latch). This terminal is internally pulled down with 100k. Timing select for serial data output. When SOMODE is low, output data on SOUT is changed synchronizing to the rising edge of SCLK. When SOMODE is high, output data on SOUT is changed synchronizing to the falling edge of SCLK. Constant current output. SOMODE 30 I OUT0 - OUT15 7,8,10,11,12,13, 15,16,17,18,20, 21,22,23,25,26 2 O BLANK I Blank(Light off). When BLANK is high, all the output of constant current driver is turned off. When BLANK is low and data written to latch is 1, the corresponding constant current output turns on (LED on). This terminal is internally pulled up with 100k. IREF 31 I Constant current value setting. LED current is set to desired value by connecting external resistor between IREF and GND. The 38 times current compared to current across external resistor sink on output terminal. Error output. XDOWN is configured as open collector. It goes low when TSD or LOD functions. Power supply voltage Ground XDOWN VCC 29 32 1 O GND PGND 6,9,14,19,24,27 Ground for LED driver. (Internally connected to GND) THERMAL PAD package bottom Heat sink pad. This pad is connected to the lowest potential to IC or thermal layer.
I/O
DESCRIPTION
absolute maximum ratings (see Note 1)
Supply voltage, VCC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . - 0.3 V to 7 V Output current (dc), IO(LC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90 mA Input voltage range, VI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . - 0.3 V to VCC + 0.3 V Output voltage range, VO(SOUT), VO(XDOWN) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . - 0.3 V to VCC + 0.3 V Output voltage range, VO(OUTn) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . - 0.3 V to 18 V Storage temperature range, Tstg . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . - 40C to 150C Continuous total power dissipation at (or below) TA = 25C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.9 W Power dissipation rating at (or above) TA = 25C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31.4 mW/C
Stresses beyond those listed under "absolute maximum ratings" 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 under "recommended operating conditions" is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability. NOTE 1: All voltage values are with respect to GND terminal.
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ac characteristics, MIN/MAX: VCC = 4.5 V to 5.5 V, TA = -20 to 85C TYP: VCC = 5 V, TA = 25C (unless otherwise noted)
dc characteristics
recommended operating conditions
Operating free-air temperature range, TA
Constant output current, IO(LC)
Low-level output current, IOL
High-level output current, IOH
Low-level input voltage, VIL
High-level input voltage, VIH
Voltage applied to constant current output, VO
Supply voltage, VCC
th
tsu
tr/tf
twh/twl twh
fSCLK
Hold time
Setup time
Rise/fall time
XLAT pulse duration
SCLK pulse duration
SCLK clock frequency
PARAMETER
PARAMETER
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XLAT - SCLK
SIN - SCLK
XLAT - SCLK
SIN - SCLK
At cascade operation (SOMODE = L)
At single operation
OUT0 to OUT15
VCC = 4.5 V, SOUT VCC = 4.5 V, SOUT, XDOWN
OUT0 to OUT15 off
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CONDITIONS CONDITIONS 0.8 VCC MIN GND - 20 4.5 MIN 20 20 10 20 5 5 NOM TYP 5 0.2 VCC MAX MAX VCC 100 -1 5.5 15 20 85 80 17 1 UNIT UNIT MHz mA mA C ns ns ns ns ns V V V V
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TLC5921 LED DRIVER
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SLLS390 - SEPTEMBER 1999
TLC5921 LED DRIVER
6 NOTE 2: At external resistor 5 k V(LEDDET) T(tsd) Vref IO(LC2) IO(LC1) IO(LC) Ilkg lk IOL(C1) IOL(C2) ICC VOL II VOH tpd tf tr Propagation delay time Fall time Rise time Reference voltage TSD detection temperature Constant output leakage current Constant output current Constant output current Supply current Input current Low-level output voltage High-level output voltage PARAMETER PARAMETER
switching characteristics, CL = 15 pF
electrical characteristics, MIN/MAX: VCC = 4.5 V to 5.5 V, TA = - 20 to 85C TYP: VCC = 5 V, TA = 25C (unless otherwise noted)
LED disconnection detection voltage
Changes in constant output current depend on output voltage
Changes in constant output current depend on supply voltage
Constant output current error between bit
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VO = 1 V, R(IREF) = 640 , All output bits turn on
VO = 1 V to 3 V, Vref = 1.3 V,
R(IREF) = 640
Junction temperature
Vref = 1.3 V
XDOWN (5V pullup)
OUT0 to OUT15 (V(OUTn) = 15 V)
VO = 1 V, VO = 1 V
Data transfer, R(IREF) = 640 ,
Data transfer, R(IREF) = 1300 ,
Input signal is static, VO = 1 V, R(IREF) = 640 , All output bits turn off
Input signal is static, VO = 1 V RIREF = 1300 , All output bits turn off
Input signal is static, VO = 1 V, R(IREF) = 10 k, All output bits turn off
IOL = 1 mA VI = VCC or GND (except BLANK, XLAT)
IOH = - 1 mA
SCLK - SOUT
BLANK - XDOWN (see Note 2)
BLANK - XDOWN (see Note 2)
BLANK - OUTn
BLANK - OUTn
OUTn
SOUT
OUTn (see Figure 1)
SOUT
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TEST CONDITIONS TEST CONDITIONS R(IREF) = 1300 R(IREF) = 640 R(IREF) = 1300 , 1 bit output turn on VO = 1 V, All output bits turn on VO = 1 V, All output bits turn on VCC -0.5V MIN MIN 150 10 70 35 TYP TYP 500 600 300 400 300 300 160 0.3 1.3 2 1 1 15 80 40 35 15 11 5 7 3 20 MAX MAX 1000 1000 400 650 170 0.1 4.5 0.5 6 4 4 1 15 90 45 50 20 15 20 1 9 35 UNIT UNIT %/V %/V mA mA mA A A A C ns ns ns % V V V V
TLC5921 LED DRIVER
SLLS390 - SEPTEMBER 1999
PARAMETER MEASUREMENT INFORMATION
VCC
51 VCC IREF 1300 GND OUTn 15 pF
Figure 1. Rise Time and Fall Time Test Circuit for OUTn
100% 90% 10% 0% tr tf td1 VIH or VOH 100% 50% VIL or VOL 0% VIL or VOL VIH or VOH
100% 50% 0% twh twl
VIH
100% 50%
VIH or VOH
VIL
0%
VIL or VOL
Figure 2. Timing Requirements
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TLC5921 LED DRIVER
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PRINCIPLES OF OPERATION setting for constant output current value
The constant current value is determined by external resistor, R(IREF) between IREF and GND. Refer constant output current characteristics shown on Figure 5 for this external resistor value. Note that more current flows if connect IREF to GND directly. constant output current operation When BLANK is low, the corresponding output is turned on if data latch value is 1, and turned off if data latch value is 0. When BLANK is high, all outputs are forced to turn off. If there is constant current output terminal left unconnected (includes LED disconnection), it should be lighted on after writing zero to corresponding data latch to its output. If this operation is not done, supply current through constant current driver will increase.
shift register latch
The shift register latch is configured with 16 x 1 bits. The 1 bit for constant current output data represents ON for constant current output if data is 1, or OFF if data is 0. The configuration of shift register latch is shown in below.
Data Latch OUT15 Data (1 bits) OUT14 Data (1 bits) OUT1 Data (1 bits) OUT0 Data (1 bits)
XLATCH
Shift Register SCLK SIN
SOUT
16
15
2
1
Figure 3. Relationship Between Shift Register and Latch
SOUT output timing selection
By setting level of SOMODE, the SOUT output timing can be changed. When SOMODE is set to low, data is clocked out to SOUT synchronized on the rising edge of SCLK, and when SOMODE is set to high, data is clocked out to SOUT synchronized on the falling edge of SCLK. When SOMODE is set to high and shift operation is done, the data shift error can be prevented even though SCLK signal is externally buffered in serial. Note that the maximum data transfer rate in cascade operation is slower than that when SMODE is set to low.
TSD (thermal shutdown)
When the junction temperature exceeds the limit, TSD starts to function and turn constant current output off and XDOWN goes low. Since XDOWN is configured with open-collector output, the outputs of multiple ICs can be concatenated. To recover from constant current output off-state to normal operation, power supply should be turned off and then turned on after several seconds.
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PRINCIPLES OF OPERATION LOD function (LED open detection)
If any terminal voltage of constant current output (OUT0 TO 15) to be turned on is approximately below 0.3 V, XDOWN output goes low during output on by knowing LED disconnection. This function is operational for sixteen OUTn individually. To know which constant current output is disconnected, the level of XDOWN is repeatedly checked 16 times from OUT0 to OUT15 turning one constant current output on. The power supply voltage for LED should be set to that the constant current output is applied to above 0.4 V to prevent from XDOWN low when LED is lighting on normally. Note that on-time should be minimum1s after the constant current output is turned on since XDOWN output is required approximately 1 s. As discussed earlier, XDOWN is used for both TSD and LOD function. Therefore, BLANK is used to know which one of TSD or LOD worked when XDOWN went low at LED disconnection, that is, in this condition, when set BLANK to high, all the constant current outputs are turned off and LOD disconnection detection is disabled, then, if XDOWN was changed to high, LED disconnection must be occurred. Table 1 is an example for XDOWN output status using four LEDs.
noise reduction : output slope
When output current is 80 mA, the time to change constant current output to turn-on and turn-off is approximately 150 ns and 250 ns respectively. This allows to reduce concurrent switching noise occurred when multiple outputs turn or off at the same time.
thermal pad
The thermal pad should be connected to GND to eliminate the noise influence since it is connected to the bottom side of IC chip. Also, desired thermal effect will be obtained by connecting this pad to the PCB pattern with better thermal conductivity.
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LED NUMBER LED STATUS OUTn 1 2 3 4 GOOD ON GOOD 1 NG ON NG 2 GOOD ON GOOD 3 NG ON NG 4 DETECTION RESULT XDOWN LED NUMBER LED STATUS OUTn LOW (by case 2, 4) GOOD ON GOOD 1 NG ON NG 2 GOOD OFF GOOD 3 NG OFF DETECTION RESULT XDOWN LED NUMBER LED STATUS OUTn GOOD 4 LOW (by case 2) GOOD OFF GOOD NG GOOD OFF GOOD NG OFF OFF DETECTION RESULT XDOWN2 GOOD GOOD HIGH-IMPEDANCE
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Table 1. XDOWN Output Example
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TLC5921 LED DRIVER
SLLS390 - SEPTEMBER 1999
PRINCIPLES OF OPERATION power rating - free-air temperature
3.9
3.2
2.0
1.48
0 -20 0 25 85 TA - Free-Air Temperature - C
0
NOTES: A. The data is based on simulation result. When TI recommended print circuit board is used, derate linearly at the rate of 31.4 mW/C for operation above 25C free-air temperature. VCC=5 V, IO(LC) = 80 mA, ICC is typical value. B. The thermal impedance will be varied depend on mounting conditions. Since PZP package established low thermal impedance by radiating heat from thermal pad, the thermal pad should be soldered to pattern with low thermal impedance. C. The material for PCB should be selected considering the thermal characteristics since the temperature will rise around the thermal pad.
Figure 4. Power Rating
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Output Voltage (Constant Current) - V
PD - Total Power Dissipation - W
TLC5921 LED DRIVER
SLLS390 - SEPTEMBER 1999
PRINCIPLES OF OPERATION constant output current
100000 66000
R(ref) - Reference Resistance - ( )
13200 10000 6000
2750 1800 1300 1040 1000 860 730 640
100 0 10 20 30 40 50 60 70 80
Ilkg - Input Leakage Current - (mA) Conditions : VO = 1 V, Vref = 1.3 V NOTE: The resistor, R(IREF), should be located as close to IREF terminal as possible to avoid the noise influence.
Figure 5. Current on Constant Current Output vs External Resistor
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SLLS390 - SEPTEMBER 1999
TLC5921 LED DRIVER
SOUT
OUTn
XDOWN
NOTE : LED disconnected
IIII IIII
12 SIN SD15_A SD00_B SD01_B SD02_B SD14_B SD15_B SD00_C SD14_C SD15_C SD00_D 1/fSCLK tsu (SIN-SCLK) SCLK th (XLAT-SCLK) XLAT tsu (XLAT-SCLK) BLANK
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Template Release Date: 7-11-94
th (SIN-SCLK)
twl (SCLK)
twh (SCLK)
SOMODE
td (SCLK-SOUT) SD00_A SD01_A SD02_A SD14_A
td (SCLK-SOUT) SD15_A SD00_B
td (SCLK-SOUT) SD01_B td (BLANK-OUTn) SD14_B SD15_B SD00_C
td (BLANK-OUTn) DRIVER OFF td (BLANK-XDOWN) (Note)
DRIVER OFF td (BLANK-XDOWN) HI-Z
DRIVER ON
Figure 6. Timing Diagram
TLC5921 LED DRIVER
SLLS390 - SEPTEMBER 1999
MECHANICAL DATA
DAP (R-PDSO-G**)
38 PINS SHOWN
PowerPADTM PLASTIC SMALL-OUTLINE PACKAGE
0,65 38
0,30 0,19 20
0,13 M
Thermal Pad (see Note D)
6,20 NOM
8,40 7,80 0,15 NOM
Gage Plane 1 A 19 0- 8 0,75 0,50 0,25
Seating Plane 1,20 MAX 0,15 0,05 0,10
PINS ** DIM A MAX
28
30
32
38
9,80
11,10
11,10
12,60
A MIN
9,60
10,90
10,90
12,40 4073257/A 07/97
NOTES: A. B. C. D.
All linear dimensions are in millimeters. This drawing is subject to change without notice. Body dimensions do not include mold flash or protrusion. The package thermal performance may be enhanced by bonding the thermal pad to an external thermal plane. This pad is electrically and thermally connected to the backside of the die and possibly selected leads. E. Falls within JEDEC MO-153
PowerPAD is a trademark of Texas Instruments Incorporated.
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IMPORTANT NOTICE Texas Instruments and its subsidiaries (TI) reserve the right to make changes to their products or to discontinue any product or service without notice, and advise customers to obtain the latest version of relevant information to verify, before placing orders, that information being relied on is current and complete. All products are sold subject to the terms and conditions of sale supplied at the time of order acknowledgement, including those pertaining to warranty, patent infringement, and limitation of liability. TI warrants performance of its semiconductor products to the specifications applicable at the time of sale in accordance with TI's standard warranty. Testing and other quality control techniques are utilized to the extent TI deems necessary to support this warranty. Specific testing of all parameters of each device is not necessarily performed, except those mandated by government requirements. CERTAIN APPLICATIONS USING SEMICONDUCTOR PRODUCTS MAY INVOLVE POTENTIAL RISKS OF DEATH, PERSONAL INJURY, OR SEVERE PROPERTY OR ENVIRONMENTAL DAMAGE ("CRITICAL APPLICATIONS"). TI SEMICONDUCTOR PRODUCTS ARE NOT DESIGNED, AUTHORIZED, OR WARRANTED TO BE SUITABLE FOR USE IN LIFE-SUPPORT DEVICES OR SYSTEMS OR OTHER CRITICAL APPLICATIONS. INCLUSION OF TI PRODUCTS IN SUCH APPLICATIONS IS UNDERSTOOD TO BE FULLY AT THE CUSTOMER'S RISK. In order to minimize risks associated with the customer's applications, adequate design and operating safeguards must be provided by the customer to minimize inherent or procedural hazards. TI assumes no liability for applications assistance or customer product design. TI does not warrant or represent that any license, either express or implied, is granted under any patent right, copyright, mask work right, or other intellectual property right of TI covering or relating to any combination, machine, or process in which such semiconductor products or services might be or are used. TI's publication of information regarding any third party's products or services does not constitute TI's approval, warranty or endorsement thereof.
Copyright (c) 1999, Texas Instruments Incorporated

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