A Bit Serial Input, Constant-Current Latched LED Driver

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1 Features and Benefits Up to 9 ma constant-current outputs Undervoltage lockout Low-power CMOS logic and latches High data input rate Functional replacement for TB6276BN/BF Packages Not to scale 24-pin DIP (A package) 24-pin SOICW (LW package) Description The A6276 is specifically designed for LED-display applications. Each BiCMOS device includes a 16-bit CMOS shift register, accompanying data latches, and 16 NPN constantcurrent sink drivers. Except for package style and allowable package power dissipation, the device options are identical. The CMOS shift register and latches allow direct interfacing with microprocessor-based systems. With a 5 V logic supply, typical serial data-input rates are up to 2 MHz. The LED drive current is de ter mined by the user selection of a single resistor. A CMOS serial data output permits cascaded connections in applications requiring additional drive lines. For inter-digit blanking, all output drivers can be disabled with an ENABLE input high. Similar 8-bit devices are available as the A6275. Two package styles are provided: through-hole DIP (suffix A) and surface-mount SOIC (suffix LW). In normal applications, the copper leadframe and low logic-power dissipation of the DIP allow it to sink maximum rated current through all outputs con tin u ous ly over the operating temperature range (9 ma,.75 V drop, 85 C). Both packages are lead (Pb) free, with % matte tin leadframe plating. Functional Block Diagram I

2 Selection Guide Part Number Package Packing Ambient Temperature ( C) A6276EA-T 24-pin DIP 15 per tube to 85 A6276ELWTR-T 24-pin SOICW per reel to 85 Absolute Maximum Ratings* Characteristic Symbol Notes Rating Units Supply Voltage V DD 7. V Output Voltage V O.5 to 17 V Input Voltage V ROUT.4 to V DD +.4 V Output Current I O 9 ma Ground Current I GND 1475 ma Operating Ambient Temperature T A Range E to 85 ºC Maximum Junction Temperature T J (max) 15 ºC Storage Temperature T stg 55 to 15 ºC *Caution: These CMOS devices have input static protection (Class 2) but are still sus cep ti ble to damage if exposed to extremely high static electrical charges. Thermal Characteristics may require derating at maximum conditions, see application information Characteristic Symbol Test Conditions* Value Units Package Thermal Resistance R θja Package A, 1-layer PCB based on JEDEC standard 5 ºC/W Package LW, 1-layer PCB based on JEDEC standard 85 ºC/W *Additional thermal information available on the Allegro website 4. ALLOWABLE PACKAGE POWER DISSIPATION IN WATTS PIN DIP, R JA = 5 C/W 24-LEAD SOIC, R JA = 85 C/W AMBIENT TEMPERATURE IN C *Mounted on single-layer, two-sided PCB, with 3.8 in 2 copper each side; additional information on Allegro Web site 2

3 Pin-out Diagram (A and LW packages) GROUND 1 V DD 24 LOGIC SUPPLY SERIAL DATA IN 2 I O REGULATOR 23 R EXT CLOCK 3 CK 22 SERIAL DATA OUT LATCH ENABLE OUT 4 5 L REGISTER LATCHES OE 21 2 OUTPUT ENABLE OUT 15 OUT OUT 14 OUT OUT 13 OUT OUT 12 OUT OUT 11 OUT OUT 1 OUT OUT 9 OUT OUT 8 Terminal Description Terminal No. Terminal Name Function 1 GND Reference terminal for control logic. 2 SERIAL DATA IN Serial-data input to the shift-register. 3 CLOCK Clock input terminal for data shift on rising edge. 4 LATCH ENABLE Data strobe input terminal; serial data is latched with high-level input. 5-2 OUT -15 The 16 current-sinking output ter mi nals. 21 OUTPUT ENABLE When (active) low, the output drivers are enabled; when high, all output drivers are turned OFF (blanked). 22 SERIAL DATA OUT CMOS serial-data output to the following shift-register. 23 R EXT An external resistor at this terminal establishes the output current for all sink drivers. 24 SUPPLY (V DD ) The logic supply voltage (typically 5 V). Copyright 2, 23 3

4 V DD V DD IN IN Dwg. EP-1-11 OUTPUT ENABLE (active low) LATCH ENABLE Dwg. EP-1-12 V DD V DD IN OUT Dwg. EP-63-6 Dwg. EP-1-13 CLOCK and SERIAL DATA IN SERIAL DATA OUT TRUTH TABLE Serial Shift Register Contents Serial Latch Latch Contents Output Output Con tents Data Clock Data Enable Enable Input Input I 1 I 2 I 3... I N-1 I N Output Input I 1 I 2 I 3... I N-1 I N Input I 1 I 2 I 3... I N-1 I N H H R 1 R 2... R N-2 R N-1 R N-1 L L R 1 R 2... R N-2 R N-1 R N-1 X R 1 R 2 R 3... R N-1 R N R N X X X... X X X L R 1 R 2 R 3... R N-1 R N P 1 P 2 P 3... P N-1 P N P N H P 1 P 2 P 3... P N-1 P N L P 1 P 2 P 3... P N-1 P N X X X... X X H H H H... H H L = Low Logic (Voltage) Level H = High Logic (Voltage) Level X = Irrelevant P = Present State R = Previous State 4

5 ELECTRICAL CHARACTERISTICS at T A = +25 C, V DD = 5 V (unless otherwise noted). Limits Characteristic Symbol Test Conditions Min. Typ. Max. Unit Supply Voltage Range V DD Operating V Under-Voltage Lockout V DD(UV) V DD = 5 V V Output Current I O V CE =.7 V, R EXT = ma (any single output) V CE =.7 V, R EXT = ma Output Current Matching I O.4 V V CE(A) = V CE(B).7 V: (difference between any R EXT = 25 ±1.5 ±6. % two outputs at same V CE ) R EXT = 47 ±1.5 ±6. % Output Leakage Current I CEX V OH = 15 V μa Logic Input Voltage V IH.7V DD V DD V V IL GND.3V DD V SERIAL DATA OUT V OL I OL = 5 μa.4 V Voltage V OH I OH = -5 μa 4.6 V Input Resistance R I ENABLE Input, Pull Up 15 3 k LATCH Input, Pull Down 2 k Supply Current I DD(OFF) R EXT = open, V OE = 5 V ma R EXT = 47 Ω, V OE = 5 V ma R EXT = 25 Ω, V OE = 5 V ma I DD(ON) R EXT = 47, V OE = V ma R EXT = 25, V OE = V ma Typical Data is at V DD = 5 V and is for design information only. 5

6 SWITCHING CHARACTERISTICS at T A = 25 C, V DD = V IH = 5 V, V CE =.4 V, V IL = V, R EXT = 47 Ω, I O = ma, V L = 3 V, R L = 65 Ω, C L = 1.5 pf. Limits Characteristic Symbol Test Conditions Min. Typ. Max. Unit Propagation Delay Time t phl CLOCK-OUT n 35 ns LATCH-OUT n 35 ns ENABLE-OUT n 35 ns CLOCK-SERIAL DATA OUT ns Propagation Delay Time t plh CLOCK-OUT n 3 ns LATCH-OUT n 3 ns ENABLE-OUT n 3 ns CLOCK-SERIAL DATA OUT ns Output Fall Time t f 9% to 1% voltage ns Output Rise Time t r 1% to 9% voltage 15 3 ns RECOMMENDED OPERATING CONDITIONS Characteristic Symbol Conditions Min. Typ. Max. Unit Supply Voltage V DD V Output Voltage V O V Output Current I O Continuous, any one output 9 ma I OH SERIAL DATA OUT -1. ma I OL SERIAL DATA OUT 1. ma Logic Input Voltage V IH.7V DD V DD +.3 V V IL -.3.3V DD V Clock Frequency f CK Cascade operation 1 MHz 6

7 TIMING REQUIREMENTS and SPECIFICATIONS (Logic Levels are V DD and Ground) C CLOCK 5% A B SERIAL DATA IN DATA 5% t p SERIAL DATA OUT 5% DATA D E LATCH ENABLE 5% OUTPUT ENABLE LOW = ALL OUTPUTS ENABLED t p HIGH = OUTPUT OFF OUT N OUTPUT ENABLE OUT N 5% F t phl 5% DATA LOW = OUTPUT ON Dwg. WP-29-1 HIGH = ALL OUTPUTS DISABLED (BLANKED) 9% t plh t f DATA t r 5% 1% Dwg. WP-3-1A A. Data Active Time Before Clock Pulse (Data Set-Up Time), t su(d)... 5 ns B. Data Active Time After Clock Pulse (Data Hold Time), t h(d)... 2 ns C. Clock Pulse Width, t w(ck)... 5 ns D. Time Between Clock Activation and Latch Enable, t su(l)... ns E. Latch Enable Pulse Width, t w(l)... ns F. Output Enable Pulse Width, t w(oe) μs NOTE: Timing is representative of a 1 MHz clock. Significantly higher speeds are attainable. Max. Clock Transition Time, t r or t f... 1 μs Serial data present at the input is transferred to the shift register on the logic -to-logic 1 transition of the CLOCK input pulse. On succeeding CLOCK pulses, the registers shift data information towards the SERIAL DATA OUTPUT. The serial data must appear at the input prior to the rising edge of the CLOCK input waveform. Information present at any register is transferred to the respective latch when the LATCH ENABLE is high (serial-topar al lel con ver sion). The latches continue to accept new data as long as the LATCH ENABLE is held high. Ap pli ca tions where the latches are bypassed (LATCH ENABLE tied high) will require that the OUTPUT EN ABLE input be high during serial data entry. When the OUTPUT ENABLE input is high, the output sink driv ers are disabled (OFF). The in for ma tion stored in the latches is not affected by the OUTPUT ENABLE input. With the OUT- PUT ENABLE input low, the outputs are con trolled by the state of their re spec tive latches. 7

8 ALLOWABLE OUTPUT CURRENT AS A FUNCTION OF DUTY CYCLE A6276EA A6276ELW VCE = 1 V VCE =.7 V ALLOWABLE OUTPUT CURRENT IN ma/bit 2 TA = +25 C VDD = 5 V R JA = 5 C/W VCE = 4 V VCE = 3 V VCE = 2 V ALLOWABLE OUTPUT CURRENT IN ma/bit 2 TA = +25 C VDD = 5 V R JA = 75 C/W VCE = 4 V VCE = 3 V VCE = 2 V VCE = 1 V 2 2 DUTY CYCLE IN PER CENT Dwg. GP DUTY CYCLE IN PER CENT Dwg. GP-62-6 VCE = 1 V VCE =.7 V ALLOWABLE OUTPUT CURRENT IN ma/bit 2 TA = +5 C VDD = 5 V R JA = 5 C/W VCE = 4 V VCE = 3 V VCE = 2 V ALLOWABLE OUTPUT CURRENT IN ma/bit 2 TA = +5 C VDD = 5 V R JA = 75 C/W VCE = 4 V VCE = 3 V VCE = 2 V VCE = 1 V 2 DUTY CYCLE IN PER CENT Dwg. GP DUTY CYCLE IN PER CENT Dwg. GP

9 ALLOWABLE OUTPUT CURRENT AS A FUNCTION OF DUTY CYCLE (cont.) A6276EA A6276ELW VCE =.7 V VCE =.4 V ALLOWABLE OUTPUT CURRENT IN ma/bit 2 TA = +85 C VDD = 5 V R JA = 5 C/W VCE = 4 V VCE = 3 V VCE = 2 V VCE = 1 V ALLOWABLE OUTPUT CURRENT IN ma/bit 2 VCE = 4 V TA = +85 C VDD = 5 V R JA = 75 C/W VCE = 3 V VCE = 2 V VCE = 1 V VCE =.7 V 2 DUTY CYCLE IN PER CENT Dwg. GP DUTY CYCLE IN PER CENT Dwg. GP-62-8 TYPICAL CHARACTERISTICS OUTPUT CURRENT IN ma/bit 2 TA = +25 C REXT = VCE IN VOLTS Dwg. GP-63 9

10 Applications Information The load current per bit (I O ) is set by the external re sis tor (R EXT ) as shown in the figure below k 2 k 3 k CURRENT-CONTROL RESISTANCE, R V CE =.7 V EXT IN OHMS 5 k Dwg. GP-61 Package Power Dissipation (P D ). The maximum allow able package power dissipation is determined as P D (max) = (15 - T A )/R JA. The actual package power dissipation is P D (act) = DC (V CE I O 16) + (V DD I DD ), where DC is the duty cycle. When the load supply voltage is greater than 3 V to 5 V, considering the package power dissipating limits of these devices, or if P D (act) > P D (max), an external voltage reducer (V DROP ) should be used. diode (V Z ), or a series string of diodes (approximately.7 V per diode) for a group of drivers. If the available voltage source will cause unacceptable dissipation and series resistors or diode(s) are undesirable, a regulator such as the Sanken Series SAI or Series SI can be used to pro vide supply voltages as low as 3.3 V. For reference, typical LED forward voltages are: White V Blue V Green V Yellow V Amber V Red V Infrared V Pattern Layout. This device has a common logic-ground and power-ground terminal. If ground pattern layout con tains large common-mode resistance, and the voltage between the system ground and the LATCH ENABLE or CLOCK terminals ex ceeds 2.5 V (because of switching noise), these devices may not operate correctly. V LED V DROP Load Supply Voltage (V LED ). These devices are designed to operate with driver voltage drops (V CE ) of.4 V to.7 V with LED forward voltages (V F ) of 1.2 V to 4. V. If higher voltages are dropped across the driver, package power dissipation will be increased significantly. To minimize package power dissipation, it is rec om - mend ed to use the lowest possible load supply voltage or to set any series dropping voltage (V DROP ) as V DROP = V LED - V F - V CE with V DROP = I o R DROP for a single driver, or a Zener V F V CE Dwg. EP-64 1

11 Package A, 24-pin DIP A MIN MAX For Reference Only (reference JEDEC MS-1 BE) Dimensions in millimeters Dimensions exclusive of mold flash, gate burrs, and dambar protrusions Exact case and lead configuration at supplier discretion within limits shown A Terminal #1 mark area ±.12 Package LW, 24-pin SOICW ±.2 4 ± ±.1 1.3± A X.1 C SEATING PLANE C SEATING PLANE GAUGE PLANE B PCB Layout Reference View.41 ± MAX.2 ±.1 For Reference Only (Reference JEDEC MS-13 AD) Dimensions exclusive of mold flash, gate burrs, and dambar protrusions Exact case and lead configuration at supplier discretion within limits shown A Terminal #1 mark area B Reference pad layout (reference IPC SOIC127P13X265-24M) All pads a minimum of.2 mm from all adjacent pads; adjust as necessary to meet application process requirements and PCB layout tolerances 11

12 Copyright 2-29, The products described here are manufactured under one or more U.S. patents or U.S. patents pending. reserves the right to make, from time to time, such de par tures from the detail spec i fi ca tions as may be required to permit improvements in the per for mance, reliability, or manufacturability of its products. Before placing an order, the user is cautioned to verify that the information being relied upon is current. Allegro s products are not to be used in life support devices or systems, if a failure of an Allegro product can reasonably be expected to cause the failure of that life support device or system, or to affect the safety or effectiveness of that device or system. The in for ma tion in clud ed herein is believed to be ac cu rate and reliable. How ev er, assumes no responsibility for its use; nor for any in fringe ment of patents or other rights of third parties which may result from its use. For the latest version of this document, visit our website: 12

Last Time Buy. Deadline for receipt of LAST TIME BUY orders: April 30, 2011

Last Time Buy. Deadline for receipt of LAST TIME BUY orders: April 30, 2011 Last Time Buy This part is in production but has been determined to be LAST TIME BUY. This classification indicates that the product is obsolete and notice has been given. Sale of this device is currently