Standard Clock Oscillators
+2 images
SIT8924BA-73-18E-33.333333
SiTime
1:
3,55 €
94 In Stock
New At Mouser
Mouser Part No
788-SIT8924BA7318E33
New At Mouser
SiTime
Standard Clock Oscillators
94 In Stock
1
3,55 €
10
3,09 €
25
2,80 €
100
2,09 €
250
1,91 €
500
View
500
1,88 €
1.000
1,80 €
2.500
1,68 €
5.000
1,61 €
Buy
Min.: 1
Mult.: 1
Details
Standard Oscillators
2 mm x 1.6 mm
33.333333 MHz
50 PPM
15 pF
1.62 V
1.98 V
LVCMOS, LVTTL
SMD/SMT
- 40 C
+ 125 V
2 mm (0.079 in)
1.6 mm (0.063 in)
0.8 mm (0.031 in)
SiT8924B
Reel, Cut Tape, MouseReel
Standard Clock Oscillators -40 to 125C, 2016, 25ppm, Default Dr Str, 2.25V-3.63V, 25MHz, OE, 250 pcs T&R 8 mm
SiT8924BA-72-XXE-25.000000G
SiTime
1:
4,04 €
1.567 In Stock
Mouser Part No
788-8924BA72XXE250G
SiTime
Standard Clock Oscillators -40 to 125C, 2016, 25ppm, Default Dr Str, 2.25V-3.63V, 25MHz, OE, 250 pcs T&R 8 mm
1.567 In Stock
1
4,04 €
10
3,51 €
25
3,18 €
100
3,05 €
250
2,88 €
500
View
500
2,77 €
1.000
2,65 €
2.500
1,76 €
5.000
1,73 €
Buy
Min.: 1
Mult.: 1
Details
Standard Oscillators
2 mm x 1.6 mm
25 MHz
25 PPM
15 pF
2.25 V
3.63 V
LVCMOS, LVTTL
SMD/SMT
- 40 C
+ 125 C
2 mm (0.079 in)
1.6 mm (0.063 in)
0.75 mm (0.03 in)
SiT8924B
Reel, Cut Tape, MouseReel
Standard Clock Oscillators 25MHz 3.3V -40C +125C
SiT8924BA-13-33E-25.000000E
SiTime
1:
1,82 €
1.296 In Stock
Mouser Part No
788-8924BA-1333E-25E
SiTime
Standard Clock Oscillators 25MHz 3.3V -40C +125C
1.296 In Stock
1
1,82 €
10
1,57 €
25
1,49 €
100
1,36 €
250
View
1.000
1,03 €
250
1,25 €
500
1,22 €
1.000
1,03 €
Buy
Min.: 1
Mult.: 1
Details
Standard Oscillators
2.5 mm x 2 mm
25 MHz
50 PPM
15 pF
2.25 V
3.63 V
LVCMOS, LVTTL
SMD/SMT
- 40 C
+ 125 C
2.5 mm (0.098 in)
2 mm (0.079 in)
0.75 mm (0.03 in)
SiT8924B
Reel, Cut Tape, MouseReel
Standard Clock Oscillators -55 to 125C, 2520, 25ppm, Default Dr Str, 3.3V, 33.333333MHz, OE, 250 pcs T&R 8 mm
SIT8924BM-12-33E-33.333333G
SiTime
1:
12,35 €
224 In Stock
250 Expected 4/3/2026
Mouser Part No
788-8924BM1233E3333G
SiTime
Standard Clock Oscillators -55 to 125C, 2520, 25ppm, Default Dr Str, 3.3V, 33.333333MHz, OE, 250 pcs T&R 8 mm
224 In Stock
250 Expected 4/3/2026
1
12,35 €
10
10,66 €
25
10,14 €
50
9,92 €
250
8,54 €
1.000
8,33 €
Buy
Min.: 1
Mult.: 1
Details
Standard Oscillators
2.5 mm x 2 mm
33.333333 MHz
25 PPM
60 pF
2.25 V
3.63 V
LVCMOS, LVTTL
SMD/SMT
- 55 C
+ 125 C
2.5 mm (0.098 in)
2 mm (0.079 in)
0.75 mm (0.03 in)
SIT8924B
Reel, Cut Tape, MouseReel
Standard Clock Oscillators -55 to 125C, 3225, 25ppm, 'E' Drive Str, 3.3V, 16MHz, NC, 250 pcs T&R 8 mm
SIT8924BME22-33N-16.000000G
SiTime
1:
10,21 €
168 In Stock
500 Expected 5/11/2026
Mouser Part No
788-8924BME2233N160G
SiTime
Standard Clock Oscillators -55 to 125C, 3225, 25ppm, 'E' Drive Str, 3.3V, 16MHz, NC, 250 pcs T&R 8 mm
168 In Stock
500 Expected 5/11/2026
1
10,21 €
10
8,55 €
250
8,33 €
Buy
Min.: 1
Mult.: 1
Details
Standard Oscillators
3.2 mm x 2.5 mm
16 MHz
25 PPM
60 pF
2.25 V
3.63 V
LVCMOS, LVTTL
SMD/SMT
- 55 C
+ 125 C
3.2 mm (0.126 in)
2.5 mm (0.098 in)
0.75 mm (0.03 in)
SIT8924B
Reel, Cut Tape, MouseReel
Standard Clock Oscillators 10MHz 3.3V -55C +125C
SiT8920AM-71-33N-10.000000G
SiTime
1:
16,57 €
195 In Stock
Mouser Part No
788-8920AM-71-33N10G
SiTime
Standard Clock Oscillators 10MHz 3.3V -55C +125C
195 In Stock
1
16,57 €
10
14,33 €
25
13,60 €
50
12,94 €
250
12,19 €
500
View
100
12,39 €
500
11,92 €
Buy
Min.: 1
Mult.: 1
Details
Standard Oscillators
2 mm x 1.6 mm
10 MHz
20 PPM
15 pF
2.97 V
3.63 V
LVCMOS
SMD/SMT
- 55 C
+ 125 C
2 mm (0.079 in)
1.6 mm (0.063 in)
0.75 mm (0.03 in)
SiT8920
Reel, Cut Tape, MouseReel
Standard Clock Oscillators -55 to 125C, 2016, 20ppm, Default Dr Str, 3.3V, 20MHz, OE, 250 pcs T&R 8 mm
SIT8924BM-71-33E-20.000000G
SiTime
1:
11,11 €
219 In Stock
250 Expected 4/28/2026
Mouser Part No
788-8924BM7133E200G
SiTime
Standard Clock Oscillators -55 to 125C, 2016, 20ppm, Default Dr Str, 3.3V, 20MHz, OE, 250 pcs T&R 8 mm
219 In Stock
250 Expected 4/28/2026
1
11,11 €
10
9,40 €
25
9,39 €
250
9,15 €
Buy
Min.: 1
Mult.: 1
Details
Standard Oscillators
2 mm x 1.6 mm
20 MHz
20 PPM
60 pF
2.25 V
3.63 V
LVCMOS, LVTTL
SMD/SMT
- 55 C
+ 125 C
2 mm (0.079 in)
1.6 mm (0.063 in)
0.75 mm (0.03 in)
SiT8924B
Reel, Cut Tape, MouseReel
Standard Clock Oscillators -55 to 125C, 2016, 20ppm, Default Dr Str, 3.3V, 100MHz, OE, 250 pcs T&R 8 mm
SIT8924BM-71-33E-100.000000G
SiTime
1:
11,11 €
246 In Stock
Mouser Part No
788-8924BM7133E100.G
SiTime
Standard Clock Oscillators -55 to 125C, 2016, 20ppm, Default Dr Str, 3.3V, 100MHz, OE, 250 pcs T&R 8 mm
246 In Stock
1
11,11 €
10
9,40 €
25
9,39 €
250
9,15 €
Buy
Min.: 1
Mult.: 1
Details
Standard Oscillators
2 mm x 1.6 mm
100 MHz
20 PPM
60 pF
2.25 V
3.63 V
LVCMOS, LVTTL
SMD/SMT
- 55 C
+ 125 C
2 mm (0.079 in)
1.6 mm (0.063 in)
0.75 mm (0.03 in)
SIT8924B
Reel, Cut Tape, MouseReel
Standard Clock Oscillators -55 to 125C, 2016, 20ppm, Default Dr Str, 3.3V, 25MHz, OE, 250 pcs T&R 8 mm
SiT8924BM-71-33E-25.000000G
SiTime
1:
13,26 €
132 In Stock
500 Expected 5/8/2026
Mouser Part No
788-8924BM7133E250G
SiTime
Standard Clock Oscillators -55 to 125C, 2016, 20ppm, Default Dr Str, 3.3V, 25MHz, OE, 250 pcs T&R 8 mm
132 In Stock
500 Expected 5/8/2026
1
13,26 €
10
11,46 €
25
10,88 €
50
10,77 €
250
9,15 €
Buy
Min.: 1
Mult.: 1
Standard Oscillators
2 mm x 1.6 mm
25 MHz
20 PPM
15 pF
2.25 V
3.63 V
LVCMOS, LVTTL
SMD/SMT
- 55 C
+ 125 C
2 mm (0.079 in)
1.6 mm (0.063 in)
0.75 mm (0.03 in)
SiT8924B
Reel, Cut Tape, MouseReel
Standard Clock Oscillators -40 to 105C, 3225, 25ppm, 3.3V, 100MHz, OE, HCSL, Default, 250 pcs T&R 8 mm
+2 images
SiT9386AE-4B2-33E100.000000G
SiTime
1:
16,91 €
195 In Stock
250 Expected 5/19/2026
Mouser Part No
788-9386AE4B233E1G
SiTime
Standard Clock Oscillators -40 to 105C, 3225, 25ppm, 3.3V, 100MHz, OE, HCSL, Default, 250 pcs T&R 8 mm
195 In Stock
250 Expected 5/19/2026
1
16,91 €
10
14,61 €
25
13,87 €
50
13,41 €
250
12,44 €
500
12,16 €
Buy
Min.: 1
Mult.: 1
Details
Standard Oscillators
3.2 mm x 2.5 mm
100 MHz
25 PPM
2 pF
2.97 V
3.63 V
LVPECL, LVDS, HCSL
SMD/SMT
- 40 C
+ 105 C
3.2 mm (0.126 in)
2.5 mm (0.098 in)
0.75 mm (0.03 in)
Reel, Cut Tape, MouseReel
Standard Clock Oscillators 25MHz 1.8V -40C +125C
SiT8924BA-72-18E-25.000000E
SiTime
1:
2,31 €
1.063 In Stock
Mouser Part No
788-8924BA-7218E-25E
SiTime
Standard Clock Oscillators 25MHz 1.8V -40C +125C
1.063 In Stock
1
2,31 €
10
2,00 €
25
1,89 €
100
1,72 €
1.000
1,37 €
5.000
View
250
1,62 €
5.000
1,34 €
Buy
Min.: 1
Mult.: 1
Details
Standard Oscillators
2 mm x 1.6 mm
25 MHz
25 PPM
15 pF
1.62 V
1.98 V
LVCMOS, LVTTL
SMD/SMT
- 40 C
+ 125 C
2 mm (0.079 in)
1.6 mm (0.063 in)
0.75 mm (0.03 in)
SiT8924B
Reel, Cut Tape, MouseReel
Standard Clock Oscillators -55 to 125C, 2520, 50ppm, Default Dr Str, 2.25V-3.63V, 50MHz, OE, 250 pcs T&R 8 mm
SIT8924BM-13-XXE-50.000000G
SiTime
1:
8,30 €
180 In Stock
Mouser Part No
788-8924BM13XXE50.G
SiTime
Standard Clock Oscillators -55 to 125C, 2520, 50ppm, Default Dr Str, 2.25V-3.63V, 50MHz, OE, 250 pcs T&R 8 mm
180 In Stock
1
8,30 €
10
7,22 €
250
7,05 €
Buy
Min.: 1
Mult.: 1
Details
Standard Oscillators
2.5 mm x 2 mm
50 MHz
50 PPM
60 pF
2.25 V
3.63 V
LVCMOS, LVTTL
SMD/SMT
- 55 C
+ 125 C
2.5 mm (0.098 in)
2 mm (0.079 in)
0.75 mm (0.03 in)
SIT8924B
Reel, Cut Tape, MouseReel
Standard Clock Oscillators -55 to 125C, 2016, 20ppm, Default Dr Str, 3.3V, 50MHz, OE, 250 pcs T&R 8 mm
SIT8924BM-71-33E-50.000000G
SiTime
1:
11,11 €
479 In Stock
Mouser Part No
788-8924BM7133E500G
SiTime
Standard Clock Oscillators -55 to 125C, 2016, 20ppm, Default Dr Str, 3.3V, 50MHz, OE, 250 pcs T&R 8 mm
479 In Stock
1
11,11 €
10
9,39 €
250
9,38 €
500
9,15 €
Buy
Min.: 1
Mult.: 1
Details
Standard Oscillators
2 mm x 1.6 mm
50 MHz
20 PPM
60 pF
2.25 V
3.63 V
LVCMOS, LVTTL
SMD/SMT
- 55 C
+ 125 C
2 mm (0.079 in)
1.6 mm (0.063 in)
0.75 mm (0.03 in)
SiT8924B
Reel, Cut Tape, MouseReel
Standard Clock Oscillators -40 to 125C, 2016, 50ppm, Default Dr Str, 1.8V, 25MHz, OE, 250 pcs T&R 8 mm
SIT8924BA-73-18E-25.000000G
SiTime
1:
3,52 €
2.557 In Stock
Mouser Part No
788-8924BA7318E25.G
SiTime
Standard Clock Oscillators -40 to 125C, 2016, 50ppm, Default Dr Str, 1.8V, 25MHz, OE, 250 pcs T&R 8 mm
2.557 In Stock
1
3,52 €
10
3,06 €
25
2,77 €
100
2,66 €
250
1,92 €
500
View
500
1,88 €
1.000
1,81 €
2.500
1,73 €
5.000
1,61 €
Buy
Min.: 1
Mult.: 1
Details
Standard Oscillators
2 mm x 1.6 mm
25 MHz
50 PPM
60 pF
1.62 V
1.98 V
LVCMOS, LVTTL
SMD/SMT
- 40 C
+ 125 C
2 mm (0.079 in)
1.6 mm (0.063 in)
0.75 mm (0.03 in)
SIT8924B
Reel, Cut Tape, MouseReel
Standard Clock Oscillators -40 to 85C, 3225, 25ppm, 3.3V, 125MHz, OE, 250 pcs T&R 12/16 mm
+2 images
SiT8209AI-22-33E-125.000000X
SiTime
1:
2,73 €
859 In Stock
Mouser Part No
788-8209AI2233E1250X
SiTime
Standard Clock Oscillators -40 to 85C, 3225, 25ppm, 3.3V, 125MHz, OE, 250 pcs T&R 12/16 mm
859 In Stock
1
2,73 €
10
2,37 €
25
2,19 €
100
2,04 €
250
1,75 €
500
View
500
1,74 €
1.000
1,71 €
2.500
1,63 €
5.000
1,57 €
Buy
Min.: 1
Mult.: 1
Details
Standard Oscillators
125 MHz
25 PPM
15 pF
2.97 V
3.63 V
LVCMOS, LVTTL
SMD/SMT
- 40 C
+ 85 C
3.2 mm (0.126 in)
2.5 mm (0.098 in)
SiT8209
Reel, Cut Tape, MouseReel
Standard Clock Oscillators -40 to 125C, 3225, 25ppm, Default Dr Str, 3.3V, 25MHz, NC, T&R
SiT8924BA-22-33N-25.000000D
SiTime
1:
2,10 €
3.351 In Stock
Mouser Part No
788-8924BA2233N25D
SiTime
Standard Clock Oscillators -40 to 125C, 3225, 25ppm, Default Dr Str, 3.3V, 25MHz, NC, T&R
3.351 In Stock
1
2,10 €
10
1,81 €
25
1,72 €
100
1,57 €
3.000
1,26 €
6.000
View
250
1,44 €
500
1,41 €
1.000
1,35 €
6.000
1,20 €
Buy
Min.: 1
Mult.: 1
Details
Standard Oscillators
3.2 mm x 2.5 mm
25 MHz
25 PPM
15 pF
2.25 V
3.63 V
LVCMOS, LVTTL
SMD/SMT
- 40 C
+ 125 C
3.2 mm (0.126 in)
2.5 mm (0.098 in)
0.75 mm (0.03 in)
SiT8924B
Reel, Cut Tape
Standard Clock Oscillators 50MHz 1.8V -40C +125C
SiT8924BA-72-18E-50.000000E
SiTime
1:
2,31 €
4.688 In Stock
Mouser Part No
788-8924BA-7218E-50E
SiTime
Standard Clock Oscillators 50MHz 1.8V -40C +125C
4.688 In Stock
1
2,31 €
10
2,00 €
25
1,89 €
100
1,72 €
250
View
1.000
1,32 €
250
1,57 €
500
1,56 €
1.000
1,32 €
Buy
Min.: 1
Mult.: 1
Details
Standard Oscillators
2 mm x 1.6 mm
50 MHz
25 PPM
15 pF
1.62 V
1.98 V
LVCMOS, LVTTL
SMD/SMT
- 40 C
+ 125 C
2 mm (0.079 in)
1.6 mm (0.063 in)
0.75 mm (0.03 in)
SiT8924B
Reel, Cut Tape, MouseReel
Standard Clock Oscillators
SiTime SIT8944BM-12-25EA25.000000
SIT8944BM-12-25EA25.000000
SiTime
1:
40,42 €
4 In Stock
Mouser Part No
788-SIT8944BM-12-25E
SiTime
Standard Clock Oscillators
4 In Stock
1
40,42 €
10
33,47 €
25
33,31 €
50
32,47 €
Buy
Min.: 1
Mult.: 1
Details
Standard Oscillators
2.5 mm x 2 mm
25 MHz
25 PPM
15 pF
2.25 V
2.75 V
LVCMOS, LVTTL
SMD/SMT
- 55 C
+ 125 C
2.5 mm (0.098 in)
2 mm (0.079 in)
0.75 mm (0.03 in)
SiT8944B
Standard Clock Oscillators 30MHz 3.3V -40C +125C
SiT1618BA-83-33E-30.000000Y
SiTime
1:
2,66 €
648 In Stock
Mouser Part No
788-1618BA-83-33E30Y
SiTime
Standard Clock Oscillators 30MHz 3.3V -40C +125C
648 In Stock
1
2,66 €
10
2,30 €
25
2,09 €
100
2,00 €
1.000
1,31 €
2.000
View
250
1,89 €
500
1,81 €
2.000
1,22 €
5.000
1,15 €
Buy
Min.: 1
Mult.: 1
Details
Standard Oscillators
7 mm x 5 mm
30 MHz
50 PPM
15 pF
2.97 V
3.63 V
LVCMOS
SMD/SMT
- 40 C
+ 125 C
7 mm (0.276 in)
5 mm (0.197 in)
0.9 mm (0.035 in)
SiT1618B
Reel, Cut Tape, MouseReel
Standard Clock Oscillators 30MHz 3.3V -40C +125C
SiT8924BA-12-33E-30.000000E
SiTime
1:
3,15 €
497 In Stock
Mouser Part No
788-8924BA-1233E-30E
SiTime
Standard Clock Oscillators 30MHz 3.3V -40C +125C
497 In Stock
1
3,15 €
10
2,72 €
25
2,58 €
100
2,35 €
1.000
1,61 €
2.000
View
250
2,15 €
500
1,81 €
2.000
1,52 €
5.000
1,50 €
Buy
Min.: 1
Mult.: 1
Details
Standard Oscillators
2.5 mm x 2 mm
30 MHz
25 PPM
15 pF
2.25 V
3.63 V
LVCMOS, LVTTL
SMD/SMT
- 40 C
+ 125 C
2.5 mm (0.098 in)
2 mm (0.079 in)
0.75 mm (0.03 in)
SiT8924B
Reel, Cut Tape, MouseReel
Standard Clock Oscillators SMD AEC-Q100 Oscillator
SIT8924BA-11-33E-100.000000G
SiTime
1:
3,94 €
612 In Stock
Mouser Part No
788-8924BA11-33E100G
SiTime
Standard Clock Oscillators SMD AEC-Q100 Oscillator
612 In Stock
1
3,94 €
10
3,40 €
25
3,23 €
100
2,93 €
250
2,67 €
500
View
500
2,64 €
1.000
1,88 €
2.500
1,77 €
5.000
1,74 €
Buy
Min.: 1
Mult.: 1
Details
Standard Oscillators
2.5 mm x 2 mm
100 MHz
20 PPM
60 pF
2.25 V
3.63 V
LVCMOS, LVTTL
SMD/SMT
- 40 C
+ 125 C
2.5 mm (0.098 in)
2 mm (0.079 in)
0.75 mm (0.03 in)
AEC-Q100
SIT8924B
Reel, Cut Tape, MouseReel
Standard Clock Oscillators -40 to 125C, 2520, 50ppm, Default Dr Str, 3.3V, 25MHz, OE, 250 pcs T&R 8 mm
SIT8924BA-13-33E-25.000000G
SiTime
1:
2,23 €
308 In Stock
Mouser Part No
788-8924BA1333E25.G
SiTime
Standard Clock Oscillators -40 to 125C, 2520, 50ppm, Default Dr Str, 3.3V, 25MHz, OE, 250 pcs T&R 8 mm
308 In Stock
1
2,23 €
10
1,92 €
25
1,82 €
100
1,65 €
250
1,40 €
1.000
View
1.000
1,38 €
2.500
1,31 €
5.000
1,27 €
Buy
Min.: 1
Mult.: 1
Details
Standard Oscillators
2.5 mm x 2 mm
25 MHz
50 PPM
60 pF
2.25 V
3.63 V
LVCMOS, LVTTL
SMD/SMT
- 40 C
+ 125 C
2.5 mm (0.098 in)
2 mm (0.079 in)
0.75 mm (0.03 in)
SIT8924B
Reel, Cut Tape, MouseReel
Standard Clock Oscillators -40 to 125C, 3225, 25ppm, Default Dr Str, 3.3V, 25MHz, NC, 250 pcs T&R 8 mm
SIT8924BA-22-33N-25.000000G
SiTime
1:
2,63 €
451 In Stock
Mouser Part No
788-8924BA2233N25.G
SiTime
Standard Clock Oscillators -40 to 125C, 3225, 25ppm, Default Dr Str, 3.3V, 25MHz, NC, 250 pcs T&R 8 mm
451 In Stock
1
2,63 €
10
2,26 €
25
2,15 €
100
1,95 €
250
1,65 €
1.000
View
1.000
1,63 €
2.500
1,56 €
5.000
1,51 €
Buy
Min.: 1
Mult.: 1
Details
Standard Oscillators
3.2 mm x 2.5 mm
25 MHz
25 PPM
60 pF
2.25 V
3.63 V
LVCMOS, LVTTL
SMD/SMT
- 40 C
+ 125 C
3.2 mm (0.126 in)
2.5 mm (0.098 in)
0.75 mm (0.03 in)
SIT8924B
Reel, Cut Tape, MouseReel
Standard Clock Oscillators 48MHz, 3.3V, 50ppm, -40 to 125C, Bulk
SIT8944BA-83-33EA48.000000
SiTime
1:
19,91 €
8 In Stock
New At Mouser
Mouser Part No
788-IT8944BA8333EA48
New At Mouser
SiTime
Standard Clock Oscillators 48MHz, 3.3V, 50ppm, -40 to 125C, Bulk
8 In Stock
1
19,91 €
10
17,21 €
25
16,33 €
50
15,55 €
100
View
100
14,89 €
250
14,69 €
500
14,33 €
Buy
Min.: 1
Mult.: 1
Details
Standard Oscillators
2820 (7050 metric
48 MHz
50 PPM
15 pF
2.25 V
3.63 V
LVCMOS, LVTTL
SMD/SMT
- 40 C
+ 125 C
7 mm (0.276 in)
5 mm (0.197 in)
SiT8944B
Bulk
Standard Clock Oscillators 50MHz, 2.25V - 3.63V, 25ppm, -55 to 125C, Bulk
SiT8944BM-12-XXEA50.000000
SiTime
1:
40,43 €
2 In Stock
New At Mouser
Mouser Part No
788-SIT8944BM12XXEA5
New At Mouser
SiTime
Standard Clock Oscillators 50MHz, 2.25V - 3.63V, 25ppm, -55 to 125C, Bulk
2 In Stock
1
40,43 €
10
35,14 €
25
33,63 €
50
33,31 €
250
32,47 €
Buy
Min.: 1
Mult.: 1
Details
Standard Oscillators
2.5 mm x 2 mm
50 MHz
25 PPM
2.25 V
3.63 V
LVCMOS, LVTTL
SMD/SMT
- 55 C
+ 125 C
2.5 mm (0.098 in)
2 mm (0.079 in)
0.75 mm (0.03 in)
SiT8944B
Bulk