A6278 ALLEGRO [Allegro MicroSystems], A6278 Datasheet
A6278
Available stocks
Related parts for A6278
A6278 Summary of contents
Page 1
... SOIC (type LW) and a TSSOP with exposed thermal pad (type LP). All package styles for the A6278 are electrically identical to each other, as are the A6279 package styles. All packages are lead (Pb) free, with 100% matte tin plated leadframes. ...
Page 2
... Part Number A6278EA-T 25 pieces per tube A6278ELP-T 96 pieces per tube A6278ELPTR-T 4000 pieces per 13-in. reel A6278ELW-T 47 pieces per tube A6278ELWTR-T 1000 pieces per 13-in. reel A6279EA-T 15 pieces per tube A6279ELP-T 65 pieces per tube A6279ELPTR-T 4000 pieces per 13-in. reel A6279ELW-T 31 pieces per tube A6279ELWTR-T 1000 pieces per 13-in ...
Page 3
... Package A, LW, LP 16-pin GND 1 SERIAL DATA IN 2 CLOCK 3 LATCH ENABLE 4 EP OUT0 5 OUT1 6 OUT2 7 OUT3 8 Terminal List Table Number A, LW, LP A6278 A6279 SERIAL DATA LATCH ENABLE OUTPUT ENABLE 14 22 SERIAL DATA OUT 15 23 ...
Page 4
... A6278 and A6279 OPERATING CHARACTERISTICS Characteristic ELECTRICAL CHARACTERISTICS valid at T LOGIC SUPPLY Voltage Range Undervoltage Lockout Output Current (any single output) Output Current Matching (difference between any two outputs at the same Output Leakage Current Logic Input Voltage Logic Input Voltage Hysteresis ...
Page 5
... L = Low logic (voltage) level H = High logic (voltage) level X = Don’t care P = Present state R = Previous state for the A6278 for the A6279 Inputs and Outputs Equivalent Circuits OUTPUT ENABLE (active low) Serial-Input, Constant-Current Latched LED Drivers with Open LED Detection ...
Page 6
... SU(LE1) H(LE1 W(OE1) SDO n Don't Care high low t H(OE1) t W(OE) t W(OE) t SU(OE P(OE) P(OE D(Total) D(Total) A6278 A6279 SDO n-1 SDO n-2 SDO 0 Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com 6 ...
Page 7
... A6278 and A6279 Normal Mode Serial data present at the SERIAL DATA IN to the shift register on the logic 0-to-logic 1 transition of the CLOCK input pulse. On succeeding CLOCK pulses, the register shifts data towards the SERIAL DATA OUT pin. The serial data must appear at the input prior to the rising edge of the CLOCK input waveform ...
Page 8
... A6279 Constant Current (R ) EXT The A6278 and A6279 allow the user to set the magnitude of the constant current to the LEDs. Once set, the current remains constant regardless of the LED voltage variation, the supply voltage variation, or other circuit parameters that could otherwise Figure 1. Output Current versus Current Control Resistance ...
Page 9
... The A6278/A6279 is then in Normal mode. Output Staggering Delay The A6278/A6279 has delay between each output. The staggering of the outputs reduces the in-rush of currents onto the power and ground planes. This aids in power supply decoupling and EMI/EMC reduction ...
Page 10
... F 3.5 to 4.0 where DC is the duty cycle. The value 16 represents the maxi- 3.0 to 4.0 mum number of available device outputs for the A6279, used for the worst-case scenario (displaying all 16 LEDs; this would be 8 1.8 to 2.2 for the A6278). 2.0 to 2.1 1.9 to 2.65 When the load suppy voltage > P 1.6 to 2.25 D(act) used (see figure 3) ...
Page 11
... A6278 and A6279 Allowable Output Current versus Duty Cycle, A6278 A Package 25° (%) LP Package 25° (%) LW Package 25° (%) Serial-Input, Constant-Current Latched LED Drivers with Open LED Detection Package 50°C ...
Page 12
... A6278 and A6279 Allowable Output Current versus Duty Cycle, A6279 A Package 25° (%) LP Package 25° (%) LW Package 25° (%) Serial-Input, Constant-Current Latched LED Drivers with Open LED Detection Package 50°C ...
Page 13
... A6278 and A6279 Characteristic Symbol Package Thermal Resistance R θJA *Additional thermal information is available on the Allegro Web site. A6278 5.0 4.0 3.0 2.0 1 100 Ambient Temperature, T Serial-Input, Constant-Current Latched LED Drivers with Open LED Detection Package Thermal Characteristics Test Conditions* A package, 16-pin, measured on 4-layer board based on JEDEC standard ...
Page 14
... MIN .070 1.78 .045 1. .005 0.13 MIN .070 1.78 .045 1.14 Serial-Input, Constant-Current Latched LED Drivers with Open LED Detection Package A, 16-pin DIP (A6278) .775 19.69 A .735 18.67 B .280 7.11 .240 6.10 .195 4.95 SEATING .115 2.92 PLANE .015 0.38 MIN Preliminary dimensions, for reference only Dimensions in inches ...
Page 15
... A6278 and A6279 Package LP, 16-pin TSSOP with Exposed Thermal Pad (A6278 16X 0.10 [.004] C 0.30 .012 16X 0.19 .007 0.10 [.004 1.85 .073 NOM 16 C 0.53 .021 REF 1 Serial-Input, Constant-Current Latched LED Drivers with Open LED Detection 5.10 .201 A 4.90 .193 B 4.5 .177 B 4.3 .169 3 .118 NOM 6.6 .260 6 ...
Page 16
... A6278 and A6279 Package LP, 24-pin TSSOP with Exposed Thermal Pad (A6279 24X 0.10 [.004] C 0.30 .012 24X 0.19 .007 0.10 [.004 1.85 .073 NOM 24 C 0.53 .021 REF 1 Serial-Input, Constant-Current Latched LED Drivers with Open LED Detection 7.9 .311 A 7.7 .303 B 4.5 .177 B 4.3 .169 3 .118 NOM 4 ...
Page 17
... A6279 16X 0.10 [.004] C 0.51 .020 16X 0.31 .012 0.25 [.010 24X 0.10 [.004] C 0.51 .020 24X 0.31 .012 0.25 [.010 Serial-Input, Constant-Current Latched LED Drivers with Open LED Detection Package LW, 16-pin SOIC (A6278) 10.63 .419 9.97 .393 0.25 [.010 10.50 .614 A 10.10 .598 B 16 7.60 .299 7.40 .291 SEATING PLANE 2 ...
Page 18
... A6278 and A6279 The products described herein are manufactured under one or more of the following U.S. patents: 5,045,920; 5,264,783; 5,442,283; 5,389,889; 5,581,179; 5,517,112; 5,619,137; 5,621,319; 5,650,719; 5,686,894; 5,694,038; 5,729,130; 5,917,320; and other patents pending. Allegro MicroSystems, Inc. reserves the right to make, from time to time, such de par tures from the detail spec tions as may be required to permit improvements in the per for mance, reliability, or manufacturability of its products ...