|
|
32-bit Microcontrollers - MCU C2000 32-bit MCU wi th 100-MHz FPU TMU
- F280041CRSHSR
- Texas Instruments
-
1:
$10.28
-
2,110In Stock
|
Mouser Part No
595-F280041CRSHSR
|
Texas Instruments
|
32-bit Microcontrollers - MCU C2000 32-bit MCU wi th 100-MHz FPU TMU
|
|
2,110In Stock
|
|
|
$10.28
|
|
|
$8.02
|
|
|
$7.45
|
|
|
$6.83
|
|
|
View
|
|
|
$5.87
|
|
|
$6.68
|
|
|
$6.66
|
|
|
$6.18
|
|
|
$5.87
|
|
|
Quote
|
|
Min.: 1
Mult.: 1
:
2,500
|
|
|
TMS320F280041C
|
SMD/SMT
|
VQFN-56
|
C28x
|
128 kB
|
100 kB
|
32 bit
|
3 x 12 bit
|
100 MHz
|
25 I/O
|
1.14 V
|
1.32 V
|
- 40 C
|
+ 125 C
|
Reel, Cut Tape, MouseReel
|
|
|
|
32-bit Microcontrollers - MCU C2000 32-bit MCU wi th 400 MIPS 1xCPU
- TMS320F28375SPZPS
- Texas Instruments
-
1:
$24.70
-
57In Stock
|
Mouser Part No
595-MS320F28375SPZPS
|
Texas Instruments
|
32-bit Microcontrollers - MCU C2000 32-bit MCU wi th 400 MIPS 1xCPU
|
|
57In Stock
|
|
|
$24.70
|
|
|
$19.33
|
|
|
$18.47
|
|
|
$16.49
|
|
|
View
|
|
|
$15.75
|
|
|
$15.22
|
|
|
Quote
|
|
Min.: 1
Mult.: 1
|
|
|
TMS320F28375S
|
SMD/SMT
|
HTQFP-100
|
|
|
|
|
12 bit
|
|
|
|
|
- 40 C
|
+ 125 C
|
|
|
|
|
32-bit Microcontrollers - MCU C2000 32-bit MCU wi th 100 MHz 64 KB fl
- TMS320F2806NMFAR
- Texas Instruments
-
1:
$24.54
-
849In Stock
|
Mouser Part No
595-TMS320F2806NMFAR
|
Texas Instruments
|
32-bit Microcontrollers - MCU C2000 32-bit MCU wi th 100 MHz 64 KB fl
|
|
849In Stock
|
|
|
$24.54
|
|
|
$19.20
|
|
|
$18.33
|
|
|
$16.40
|
|
|
View
|
|
|
$14.36
|
|
|
$15.64
|
|
|
$15.12
|
|
|
$14.36
|
|
|
Quote
|
|
Min.: 1
Mult.: 1
:
1,000
|
|
|
TMS320F2806
|
SMD/SMT
|
NFBGA-100
|
C28x
|
32 kB
|
10 kB
|
32 bit
|
12 bit
|
100 MHz
|
35 I/O
|
1.71 V
|
1.89 V
|
- 40 C
|
+ 85 C
|
Reel, Cut Tape, MouseReel
|
|
|
|
32-bit Microcontrollers - MCU Piccolo Micro contro ller
- TMS320F28030RSHT
- Texas Instruments
-
1:
$11.20
-
260In Stock
|
Mouser Part No
595-TMS320F28030RSHT
|
Texas Instruments
|
32-bit Microcontrollers - MCU Piccolo Micro contro ller
|
|
260In Stock
|
|
|
$11.20
|
|
|
$8.66
|
|
|
$8.26
|
|
|
$7.18
|
|
|
View
|
|
|
$5.93
|
|
|
$5.91
|
|
|
$5.48
|
|
|
$5.27
|
|
|
Quote
|
|
Min.: 1
Mult.: 1
|
|
|
TMS320F28030
|
SMD/SMT
|
VQFN-56
|
C28x
|
16 kB
|
6 kB
|
32 bit
|
12 bit
|
60 MHz
|
26 I/O
|
1.71 V
|
1.955 V
|
- 40 C
|
+ 125 C
|
Tray
|
|
|
|
32-bit Microcontrollers - MCU C2000 32-bit MCU wi th 60 MHz 64 KB fla
- TMS320F28032PNTR
- Texas Instruments
-
1:
$12.07
-
2,000In Stock
|
Mouser Part No
595-TMS320F28032PNTR
|
Texas Instruments
|
32-bit Microcontrollers - MCU C2000 32-bit MCU wi th 60 MHz 64 KB fla
|
|
2,000In Stock
|
|
|
$12.07
|
|
|
$9.40
|
|
|
$8.96
|
|
|
$7.77
|
|
|
$6.11
|
|
|
View
|
|
|
$7.42
|
|
|
$6.77
|
|
|
$5.78
|
|
Min.: 1
Mult.: 1
:
1,000
|
|
|
TMS320F28032
|
SMD/SMT
|
LQFP-80
|
C28x
|
32 kB
|
10 kB
|
32 bit
|
12 bit
|
60 MHz
|
33 I/O
|
2.97 V
|
3.63 V
|
- 40 C
|
+ 105 C
|
Reel, Cut Tape, MouseReel
|
|
|
|
32-bit Microcontrollers - MCU Piccolo MCU
- TMS320F28035RSHS
- Texas Instruments
-
1:
$16.11
-
87In Stock
|
Mouser Part No
595-TMS320F28035RSHS
|
Texas Instruments
|
32-bit Microcontrollers - MCU Piccolo MCU
|
|
87In Stock
|
|
|
$16.11
|
|
|
$12.76
|
|
|
$11.91
|
|
|
$10.99
|
|
|
View
|
|
|
$10.54
|
|
|
$10.26
|
|
|
$10.04
|
|
|
Quote
|
|
Min.: 1
Mult.: 1
|
|
|
TMS320F28035
|
SMD/SMT
|
VQFN-56
|
C28x
|
64 kB
|
10 kB
|
32 bit
|
12 bit
|
60 MHz
|
45 I/O
|
1.71 V
|
1.955 V
|
- 40 C
|
+ 125 C
|
Tray
|
|
|
|
32-bit Microcontrollers - MCU C2000 32-bit MCU wi th 100 MHz FPU TMU
- F280023CPNSR
- Texas Instruments
-
1:
$9.06
-
1,975In Stock
|
Mouser Part No
595-F280023CPNSR
|
Texas Instruments
|
32-bit Microcontrollers - MCU C2000 32-bit MCU wi th 100 MHz FPU TMU
|
|
1,975In Stock
|
|
|
$9.06
|
|
|
$6.79
|
|
|
$6.48
|
|
|
$5.62
|
|
|
$4.16
|
|
|
View
|
|
|
$5.37
|
|
|
$4.90
|
|
|
$4.15
|
|
|
Quote
|
|
Min.: 1
Mult.: 1
:
1,000
|
|
|
TMS320F280023C
|
SMD/SMT
|
LQFP-80
|
C28x
|
64 kB
|
24 kB
|
32 bit
|
2 x 12 bit
|
100 MHz
|
39 I/O
|
2.8 V
|
3.63 V
|
- 40 C
|
+ 125 C
|
Reel, Cut Tape, MouseReel
|
|
|
|
32-bit Microcontrollers - MCU Automotive C2000 32 -bit MCU with 100 MH
- F280023PMQR
- Texas Instruments
-
1:
$8.06
-
1,996In Stock
|
Mouser Part No
595-F280023PMQR
|
Texas Instruments
|
32-bit Microcontrollers - MCU Automotive C2000 32 -bit MCU with 100 MH
|
|
1,996In Stock
|
|
|
$8.06
|
|
|
$5.63
|
|
|
$5.37
|
|
|
$4.66
|
|
|
View
|
|
|
$3.45
|
|
|
$4.45
|
|
|
$4.06
|
|
|
$3.45
|
|
Min.: 1
Mult.: 1
:
1,000
|
|
|
TMS320F280023
|
SMD/SMT
|
LQFP-64
|
C28x
|
64 kB
|
24 kB
|
32 bit
|
2 x 12 bit
|
100 MHz
|
26 I/O
|
2.8 V
|
3.63 V
|
- 40 C
|
+ 125 C
|
Reel, Cut Tape, MouseReel
|
|
|
|
32-bit Microcontrollers - MCU Delfino MCU
- TMS320C28345ZFET
- Texas Instruments
-
1:
$32.22
-
90In Stock
|
Mouser Part No
595-TMS320C28345ZFET
|
Texas Instruments
|
32-bit Microcontrollers - MCU Delfino MCU
|
|
90In Stock
|
|
|
$32.22
|
|
|
$25.20
|
|
|
$20.90
|
|
|
$20.89
|
|
|
View
|
|
|
$20.49
|
|
|
$19.97
|
|
|
Quote
|
|
Min.: 1
Mult.: 1
|
|
|
TMS320C28345
|
SMD/SMT
|
BGA-256
|
C28x
|
16 kB
|
516 kB
|
32 bit
|
12 bit
|
200 MHz
|
88 I/O
|
1.05 V
|
1.16 V
|
- 40 C
|
+ 105 C
|
Tray
|
|
|
|
32-bit Microcontrollers - MCU PICCOLO MCU
- TMS320F28069UPNT
- Texas Instruments
-
1:
$23.42
-
68In Stock
|
Mouser Part No
595-TMS320F28069UPNT
|
Texas Instruments
|
32-bit Microcontrollers - MCU PICCOLO MCU
|
|
68In Stock
|
|
|
$23.42
|
|
|
$18.33
|
|
|
$17.50
|
|
|
$15.63
|
|
|
View
|
|
|
$14.41
|
|
|
$14.10
|
|
|
Quote
|
|
Min.: 1
Mult.: 1
|
|
|
TMS320F28069
|
SMD/SMT
|
LQFP-80
|
C28x
|
256 kB
|
100 kB
|
32 bit
|
12 bit
|
80 MHz
|
40 I/O
|
1.71 V
|
1.89 V
|
- 40 C
|
+ 105 C
|
Tray
|
|
|
|
32-bit Microcontrollers - MCU C2000 32-bit MCU wi th 100 MHz 64 KB fl A 595-TMS320F2806NMFS
- TMS320F2806NMFA
- Texas Instruments
-
1:
$27.26
-
184In Stock
|
Mouser Part No
595-TMS320F2806NMFA
|
Texas Instruments
|
32-bit Microcontrollers - MCU C2000 32-bit MCU wi th 100 MHz 64 KB fl A 595-TMS320F2806NMFS
|
|
184In Stock
|
|
|
$27.26
|
|
|
$21.95
|
|
|
$20.61
|
|
|
$17.99
|
|
|
View
|
|
|
$17.98
|
|
|
$17.67
|
|
|
Quote
|
|
Min.: 1
Mult.: 1
|
|
|
TMS320F2806
|
SMD/SMT
|
NFBGA-100
|
C28x
|
64 kB
|
20 kB
|
32 bit
|
12 bit
|
100 MHz
|
35 I/O
|
1.71 V
|
1.89 V
|
- 40 C
|
+ 85 C
|
Tray
|
|
|
|
32-bit Microcontrollers - MCU Automotive C2000 32 -bit MCU with 100 MH
- F280040CPMQR
- Texas Instruments
-
1:
$10.59
-
675In Stock
|
Mouser Part No
595-F280040CPMQR
|
Texas Instruments
|
32-bit Microcontrollers - MCU Automotive C2000 32 -bit MCU with 100 MH
|
|
675In Stock
|
|
|
$10.59
|
|
|
$9.69
|
|
|
$9.46
|
|
|
$8.75
|
|
|
$6.85
|
|
|
View
|
|
|
$8.35
|
|
|
$7.61
|
|
|
$6.59
|
|
|
Quote
|
|
Min.: 1
Mult.: 1
:
1,000
|
|
|
TMS320F280040C
|
SMD/SMT
|
LQFP-64
|
C28x
|
128 kB
|
100 kB
|
32 bit
|
3 x 12 bit
|
100 MHz
|
24 I/O
|
1.14 V
|
1.32 V
|
- 40 C
|
+ 125 C
|
Reel, Cut Tape, MouseReel
|
|
|
|
32-bit Microcontrollers - MCU C2000 32-bit MCU wi th 100 MHz FPU TMU
- F280045RSHSR
- Texas Instruments
-
1:
$9.91
-
2,389In Stock
|
Mouser Part No
595-F280045RSHSR
|
Texas Instruments
|
32-bit Microcontrollers - MCU C2000 32-bit MCU wi th 100 MHz FPU TMU
|
|
2,389In Stock
|
|
|
$9.91
|
|
|
$7.72
|
|
|
$7.18
|
|
|
$6.57
|
|
|
View
|
|
|
$5.54
|
|
|
$6.28
|
|
|
$6.11
|
|
|
$5.92
|
|
|
$5.54
|
|
|
Quote
|
|
Min.: 1
Mult.: 1
:
2,500
|
|
|
TMS320F280045
|
SMD/SMT
|
VQFN-56
|
C28x
|
256 kB
|
100 kB
|
32 bit
|
3 x 12 bit
|
100 MHz
|
25 I/O
|
1.14 V
|
1.32 V
|
- 40 C
|
+ 125 C
|
Reel, Cut Tape, MouseReel
|
|
|
|
32-bit Microcontrollers - MCU Piccolo MCU A 595-TM S320F28052MPNT A 59 A 595-TMS320F28052MPNT
- TMS320F28052PNT
- Texas Instruments
-
1:
$10.11
-
524In Stock
|
Mouser Part No
595-TMS320F28052PNT
|
Texas Instruments
|
32-bit Microcontrollers - MCU Piccolo MCU A 595-TM S320F28052MPNT A 59 A 595-TMS320F28052MPNT
|
|
524In Stock
|
|
|
$10.11
|
|
|
$7.58
|
|
|
$7.30
|
|
|
$6.20
|
|
|
View
|
|
|
$5.99
|
|
|
$5.28
|
|
|
$5.01
|
|
|
$4.92
|
|
|
Quote
|
|
Min.: 1
Mult.: 1
|
|
|
TMS320F28052
|
SMD/SMT
|
LQFP-80
|
C28x
|
32 kB
|
10 kB
|
32 bit
|
12 bit
|
60 MHz
|
42 I/O
|
1.8 V
|
1.8 V
|
- 40 C
|
+ 125 C
|
Tray
|
|
|
|
32-bit Microcontrollers - MCU Piccolo MicroCntlr
- TMS320F28055PNS
- Texas Instruments
-
1:
$18.72
-
74In Stock
|
Mouser Part No
595-TMS320F28055PNS
|
Texas Instruments
|
32-bit Microcontrollers - MCU Piccolo MicroCntlr
|
|
74In Stock
|
|
|
$18.72
|
|
|
$14.22
|
|
|
$13.64
|
|
|
$11.25
|
|
|
View
|
|
|
$11.03
|
|
|
$10.66
|
|
|
$10.26
|
|
|
Quote
|
|
Min.: 1
Mult.: 1
|
|
|
TMS320F28055
|
SMD/SMT
|
LQFP-80
|
C28x
|
128 kB
|
20 kB
|
32 bit
|
12 bit
|
60 MHz
|
42 I/O
|
1.71 V
|
1.995 V
|
- 40 C
|
+ 125 C
|
Tray
|
|
|
|
32-bit Microcontrollers - MCU Piccolo MCU
- TMS320F28068FPZT
- Texas Instruments
-
1:
$24.28
-
270In Stock
|
Mouser Part No
595-TMS320F28068FPZT
|
Texas Instruments
|
32-bit Microcontrollers - MCU Piccolo MCU
|
|
270In Stock
|
|
|
$24.28
|
|
|
$19.00
|
|
|
$15.68
|
|
|
$14.97
|
|
|
$14.96
|
|
Min.: 1
Mult.: 1
|
|
|
TMS320F28068F
|
SMD/SMT
|
LQFP-100
|
C28x
|
|
|
32 bit
|
12 bit
|
|
|
1.71 V
|
1.89 V
|
- 40 C
|
+ 105 C
|
Tray
|
|
|
|
32-bit Microcontrollers - MCU C2000 32-bit MCU wi th 100-MHz 128-kb f A 595-TMS320F2808GBAS
- TMS320F2808GBAA
- Texas Instruments
-
1:
$31.18
-
358In Stock
|
Mouser Part No
595-TMS320F2808GBAA
|
Texas Instruments
|
32-bit Microcontrollers - MCU C2000 32-bit MCU wi th 100-MHz 128-kb f A 595-TMS320F2808GBAS
|
|
358In Stock
|
|
|
$31.18
|
|
|
$24.39
|
|
|
$23.29
|
|
|
$20.83
|
|
|
View
|
|
|
$19.85
|
|
|
$19.20
|
|
|
Quote
|
|
Min.: 1
Mult.: 1
|
No
|
|
TMS320F2808
|
SMD/SMT
|
NFBGA-100
|
C28x
|
128 kB
|
36 kB
|
32 bit
|
12 bit
|
100 MHz
|
35 I/O
|
1.71 V
|
1.89 V
|
- 40 C
|
+ 85 C
|
Tray
|
|
|
|
32-bit Microcontrollers - MCU Radiation-tolerant 3 2-bit MCU with 800M
- F28377DPTPSEP
- Texas Instruments
-
1:
$3,863.87
-
1In Stock
-
New Product
|
Mouser Part No
595-F28377DPTPSEP
New Product
|
Texas Instruments
|
32-bit Microcontrollers - MCU Radiation-tolerant 3 2-bit MCU with 800M
|
|
1In Stock
|
|
Min.: 1
Mult.: 1
|
|
|
F28377DPTPSEP
|
SMD/SMT
|
HLQFP-176
|
C28x
|
1 MB
|
2 MB
|
32 bit
|
16 bit
|
200 MHz
|
97 I/O
|
1.14 V
|
3.47 V
|
- 55 C
|
+ 125 C
|
Tray
|
|
|
|
32-bit Microcontrollers - MCU Automotive C2000 32- bit MCU with 150MHz
- F28P559SJ6PZRQ1
- Texas Instruments
-
1:
$12.92
-
700In Stock
-
New Product
|
Mouser Part No
595-F28P559SJ6PZRQ1
New Product
|
Texas Instruments
|
32-bit Microcontrollers - MCU Automotive C2000 32- bit MCU with 150MHz
|
|
700In Stock
|
|
|
$12.92
|
|
|
$9.82
|
|
|
$9.41
|
|
|
$8.29
|
|
|
View
|
|
|
$6.65
|
|
|
$7.89
|
|
|
$7.83
|
|
|
$6.65
|
|
Min.: 1
Mult.: 1
:
1,000
|
|
|
TMS320F28P559SJ-Q1
|
SMD/SMT
|
LQFP-100
|
C28x
|
1 MB
|
133 kB
|
32 bit
|
12 bit
|
150 MHz
|
43 I/O
|
1.14 V
|
1.32 V
|
- 40 C
|
+ 150 C
|
Reel, Cut Tape, MouseReel
|
|
|
|
32-bit Microcontrollers - MCU C2000 32-bit MCU wi th 100-MHz 128-kb f A 595-TMS320F2808GBAA
- TMS320F2808GBAS
- Texas Instruments
-
1:
$34.29
-
184In Stock
|
Mouser Part No
595-TMS320F2808GBAS
|
Texas Instruments
|
32-bit Microcontrollers - MCU C2000 32-bit MCU wi th 100-MHz 128-kb f A 595-TMS320F2808GBAA
|
|
184In Stock
|
|
|
$34.29
|
|
|
$26.83
|
|
|
$25.61
|
|
|
$22.90
|
|
|
View
|
|
|
$21.84
|
|
|
$21.12
|
|
|
Quote
|
|
Min.: 1
Mult.: 1
|
No
|
|
TMS320F2808
|
SMD/SMT
|
NFBGA-100
|
C28x
|
128 kB
|
36 kB
|
32 bit
|
12 bit
|
100 MHz
|
35 I/O
|
1.71 V
|
1.89 V
|
- 40 C
|
+ 125 C
|
Tray
|
|
|
|
32-bit Microcontrollers - MCU Piccolo Micro
- TMS320F28022DAS
- Texas Instruments
-
1:
$9.46
-
200In Stock
|
Mouser Part No
595-TMS320F28022DAS
|
Texas Instruments
|
32-bit Microcontrollers - MCU Piccolo Micro
|
|
200In Stock
|
|
|
$9.46
|
|
|
$7.08
|
|
|
$6.76
|
|
|
$5.02
|
|
|
View
|
|
|
$4.92
|
|
|
$4.61
|
|
|
$4.40
|
|
Min.: 1
Mult.: 1
|
|
|
TMS320F28022
|
SMD/SMT
|
TSSOP-38
|
C28x
|
32 kB
|
12 kB
|
32 bit
|
12 bit
|
50 MHz
|
20 I/O
|
1.71 V
|
1.89 V
|
- 40 C
|
+ 125 C
|
|
|
|
|
32-bit Microcontrollers - MCU Piccolo MCU
- TMS320F280230PTT
- Texas Instruments
-
1:
$7.13
-
206In Stock
|
Mouser Part No
595-TMS320F280230PTT
|
Texas Instruments
|
32-bit Microcontrollers - MCU Piccolo MCU
|
|
206In Stock
|
|
|
$7.13
|
|
|
$5.34
|
|
|
$4.95
|
|
|
$4.42
|
|
|
View
|
|
|
$3.77
|
|
|
$3.66
|
|
|
$3.47
|
|
|
$3.41
|
|
|
Quote
|
|
Min.: 1
Mult.: 1
|
|
|
TMS320F280230
|
SMD/SMT
|
LQFP-48
|
C28x
|
16 kB
|
4 kB
|
32 bit
|
12 bit
|
40 MHz
|
22 I/O
|
1.71 V
|
1.89 V
|
- 40 C
|
+ 125 C
|
Tray
|
|
|
|
32-bit Microcontrollers - MCU Piccolo MCU A 595-TM S320F28026DATR A 59 A 595-TMS320F28026DATR
- TMS320F28026DAT
- Texas Instruments
-
1:
$9.29
-
200In Stock
|
Mouser Part No
595-TMS320F28026DAT
|
Texas Instruments
|
32-bit Microcontrollers - MCU Piccolo MCU A 595-TM S320F28026DATR A 59 A 595-TMS320F28026DATR
|
|
200In Stock
|
|
|
$9.29
|
|
|
$7.19
|
|
|
$6.68
|
|
|
$5.45
|
|
|
View
|
|
|
$5.34
|
|
|
$5.21
|
|
|
$4.97
|
|
|
$4.77
|
|
Min.: 1
Mult.: 1
|
|
|
TMS320F28026
|
SMD/SMT
|
TSSOP-38
|
C28x
|
16 kB
|
6 kB
|
32 bit
|
12 bit
|
60 MHz
|
20 I/O
|
1.71 V
|
1.89 V
|
- 40 C
|
+ 125 C
|
Tube
|
|
|
|
32-bit Microcontrollers - MCU PICCOLO MCU
- TMS320F28062UPZT
- Texas Instruments
-
1:
$18.72
-
73In Stock
|
Mouser Part No
595-TMS320F28062UPZT
|
Texas Instruments
|
32-bit Microcontrollers - MCU PICCOLO MCU
|
|
73In Stock
|
|
|
$18.72
|
|
|
$15.13
|
|
|
$14.51
|
|
|
$11.94
|
|
|
View
|
|
|
$11.72
|
|
|
$11.36
|
|
|
$11.34
|
|
|
Quote
|
|
Min.: 1
Mult.: 1
|
|
|
TMS320F28062
|
SMD/SMT
|
LQFP-100
|
C28x
|
256 kB
|
52 kB
|
32 bit
|
|
80 MHz
|
54 I/O
|
1.71 V
|
1.89 V
|
- 40 C
|
+ 105 C
|
Tray
|
|
|
|
32-bit Microcontrollers - MCU C2000 32-bit MCU wi th 100-MHz FPU TMU A A 595-F280025CPMSR
- F280025CPMS
- Texas Instruments
-
1:
$9.72
-
158In Stock
|
Mouser Part No
595-F280025CPMS
|
Texas Instruments
|
32-bit Microcontrollers - MCU C2000 32-bit MCU wi th 100-MHz FPU TMU A A 595-F280025CPMSR
|
|
158In Stock
|
|
|
$9.72
|
|
|
$7.29
|
|
|
$6.95
|
|
|
$6.04
|
|
|
View
|
|
|
$5.76
|
|
|
$5.26
|
|
|
$4.73
|
|
|
$4.45
|
|
|
Quote
|
|
Min.: 1
Mult.: 1
|
|
|
TMS320F280025C
|
SMD/SMT
|
LQFP-64
|
C28x
|
128 kB
|
24 kB
|
32 bit
|
2 x 12 bit
|
100 MHz
|
26 I/O
|
2.8 V
|
3.63 V
|
- 40 C
|
+ 125 C
|
Tray
|
|
South Africa