|
|
RS-422/RS-485 Interface IC Differential Bus Tra nsceiver ALT 595-SN ALT 595-SN75ALS176P
- SN75ALS176PE4
- Texas Instruments
-
1:
$8.59
-
420In Stock
|
Mouser Part No
595-SN75ALS176PE4
|
Texas Instruments
|
RS-422/RS-485 Interface IC Differential Bus Tra nsceiver ALT 595-SN ALT 595-SN75ALS176P
|
|
420In Stock
|
|
|
$8.59
|
|
|
$5.91
|
|
|
$5.02
|
|
|
$4.83
|
|
|
View
|
|
|
$3.27
|
|
|
$3.22
|
|
|
$3.00
|
|
Min.: 1
Mult.: 1
|
|
|
SN75ALS176
|
Through Hole
|
PDIP-8
|
Transceiver
|
1 Driver
|
1 Receiver
|
35 Mb/s
|
5 V
|
5 V
|
0 C
|
+ 70 C
|
Tube
|
|
|
|
RS-422/RS-485 Interface IC Quad LP Diff
- SN65LBC173AN
- Texas Instruments
-
1:
$13.34
-
177In Stock
|
Mouser Part No
595-SN65LBC173AN
|
Texas Instruments
|
RS-422/RS-485 Interface IC Quad LP Diff
|
|
177In Stock
|
|
|
$13.34
|
|
|
$10.40
|
|
|
$9.64
|
|
|
$8.82
|
|
|
View
|
|
|
$8.44
|
|
|
$8.21
|
|
|
$7.89
|
|
|
Quote
|
|
Min.: 1
Mult.: 1
|
|
|
SN65LBC173A
|
Through Hole
|
PDIP-16
|
Receiver
|
0 Driver
|
4 Receiver
|
50 Mb/s
|
5 V
|
5 V
|
- 40 C
|
+ 85 C
|
Tube
|
|
|
|
RS-422/RS-485 Interface IC 70V Fault-Protected RS-485 Xcvrs ALT 595 ALT 595-SN65HVD1785DR
- SN65HVD1785DRG4
- Texas Instruments
-
1:
$9.45
-
1,659In Stock
|
Mouser Part No
595-SN65HVD1785DRG4
|
Texas Instruments
|
RS-422/RS-485 Interface IC 70V Fault-Protected RS-485 Xcvrs ALT 595 ALT 595-SN65HVD1785DR
|
|
1,659In Stock
|
|
|
$9.45
|
|
|
$6.95
|
|
|
$6.48
|
|
|
$5.69
|
|
|
View
|
|
|
$3.53
|
|
|
$5.41
|
|
|
$4.85
|
|
|
$4.09
|
|
|
$3.53
|
|
|
Quote
|
|
Min.: 1
Mult.: 1
|
|
|
SN65HVD1785
|
SMD/SMT
|
SOIC-8
|
Transceiver
|
1 Driver
|
1 Receiver
|
115 kb/s
|
5.5 V
|
4.5 V
|
- 40 C
|
+ 105 C
|
Reel, Cut Tape, MouseReel
|
|
|
|
RS-422/RS-485 Interface IC Dual Diff
- SN75ALS1178N
- Texas Instruments
-
1:
$11.28
-
191In Stock
|
Mouser Part No
595-SN75ALS1178N
|
Texas Instruments
|
RS-422/RS-485 Interface IC Dual Diff
|
|
191In Stock
|
|
|
$11.28
|
|
|
$8.74
|
|
|
$8.08
|
|
|
$7.38
|
|
|
View
|
|
|
$7.05
|
|
|
$6.85
|
|
|
$6.61
|
|
|
Quote
|
|
Min.: 1
Mult.: 1
|
|
|
SN75ALS1178
|
Through Hole
|
PDIP-16
|
Transceiver
|
2 Driver
|
2 Receiver
|
10 Mb/s
|
5 V
|
5 V
|
0 C
|
+ 70 C
|
Tube
|
|
|
|
RS-422/RS-485 Interface IC Differential Bus Tra nsceiver
- SN75ALS176AP
- Texas Instruments
-
1:
$9.55
-
351In Stock
|
Mouser Part No
595-SN75ALS176AP
|
Texas Instruments
|
RS-422/RS-485 Interface IC Differential Bus Tra nsceiver
|
|
351In Stock
|
|
|
$9.55
|
|
|
$7.02
|
|
|
$6.54
|
|
|
$5.73
|
|
|
View
|
|
|
$4.78
|
|
|
$4.25
|
|
|
$4.15
|
|
|
$4.06
|
|
|
Quote
|
|
Min.: 1
Mult.: 1
|
|
|
SN75ALS176A
|
Through Hole
|
PDIP-8
|
Transceiver
|
1 Driver
|
1 Receiver
|
35 Mb/s
|
5 V
|
5 V
|
0 C
|
+ 70 C
|
Tube
|
|
|
|
RS-422/RS-485 Interface IC Dual Diff
- SN75ALS1177N
- Texas Instruments
-
1:
$11.28
-
264In Stock
|
Mouser Part No
595-SN75ALS1177N
|
Texas Instruments
|
RS-422/RS-485 Interface IC Dual Diff
|
|
264In Stock
|
|
|
$11.28
|
|
|
$8.74
|
|
|
$8.08
|
|
|
$7.38
|
|
|
View
|
|
|
$7.05
|
|
|
$6.85
|
|
|
$6.68
|
|
|
Quote
|
|
Min.: 1
Mult.: 1
|
|
|
SN75ALS1177
|
Through Hole
|
PDIP-16
|
Transceiver
|
2 Driver
|
2 Receiver
|
10 Mb/s
|
5 V
|
5 V
|
0 C
|
+ 70 C
|
Tube
|
|
|
|
RS-422/RS-485 Interface IC Quad Diff Line Rec
- SN75LBC173N
- Texas Instruments
-
1:
$12.48
-
268In Stock
|
Mouser Part No
595-SN75LBC173N
|
Texas Instruments
|
RS-422/RS-485 Interface IC Quad Diff Line Rec
|
|
268In Stock
|
|
|
$12.48
|
|
|
$9.37
|
|
|
$8.92
|
|
|
$6.92
|
|
|
View
|
|
|
$6.72
|
|
|
$6.54
|
|
|
$5.93
|
|
|
$5.76
|
|
|
Quote
|
|
Min.: 1
Mult.: 1
|
|
|
SN75LBC173
|
Through Hole
|
PDIP-16
|
Receiver
|
0 Driver
|
4 Receiver
|
10 Mb/s
|
5 V
|
5 V
|
0 C
|
+ 70 C
|
Tube
|
|
|
|
RS-422/RS-485 Interface IC Radiation-tolerant 3 V to 5.5V RS-485 tr
- THVD9491DTSEP
- Texas Instruments
-
1:
$576.99
-
1,161In Stock
-
250On Order
-
New Product
|
Mouser Part No
595-THVD9491DTSEP
New Product
|
Texas Instruments
|
RS-422/RS-485 Interface IC Radiation-tolerant 3 V to 5.5V RS-485 tr
|
|
1,161In Stock
250On Order
|
|
|
$576.99
|
|
|
$498.94
|
|
|
$480.38
|
|
|
$447.32
|
|
Min.: 1
Mult.: 1
|
|
|
THVD9491
|
SMD/SMT
|
SOIC-14
|
Transceiver
|
1 Driver
|
1 Receiver
|
50 Mb/s
|
5.5 V
|
3 V
|
- 40 C
|
+ 125 C
|
Reel, Cut Tape, MouseReel
|
|
|
|
RS-422/RS-485 Interface IC 3.3-V to 5-V 250-Kb ps full-duplex RS-4
- THVD2412DRCR
- Texas Instruments
-
1:
$6.21
-
4,726In Stock
-
New Product
|
Mouser Part No
595-THVD2412DRCR
New Product
|
Texas Instruments
|
RS-422/RS-485 Interface IC 3.3-V to 5-V 250-Kb ps full-duplex RS-4
|
|
4,726In Stock
|
|
|
$6.21
|
|
|
$4.72
|
|
|
$4.33
|
|
|
$3.92
|
|
|
View
|
|
|
$3.33
|
|
|
$3.73
|
|
|
$3.60
|
|
|
$3.52
|
|
|
$3.40
|
|
|
$3.33
|
|
Min.: 1
Mult.: 1
|
|
|
THVD2412
|
SMD/SMT
|
VSON-10
|
Transceiver
|
1 Driver
|
1 Receiver
|
250 kb/s
|
5.5 V
|
3 V
|
- 40 C
|
+ 125 C
|
Reel, Cut Tape, MouseReel
|
|
|
|
RS-422/RS-485 Interface IC 3-V to 5.5-V 1-Mbps full-duplex RS-485
- THVD2412VDR
- Texas Instruments
-
1:
$7.54
-
2,995In Stock
-
New Product
|
Mouser Part No
595-THVD2412VDR
New Product
|
Texas Instruments
|
RS-422/RS-485 Interface IC 3-V to 5.5-V 1-Mbps full-duplex RS-485
|
|
2,995In Stock
|
|
|
$7.54
|
|
|
$5.76
|
|
|
$5.31
|
|
|
$4.82
|
|
|
View
|
|
|
$4.29
|
|
|
$4.59
|
|
|
$4.45
|
|
|
$4.33
|
|
|
$4.29
|
|
|
Quote
|
|
Min.: 1
Mult.: 1
|
|
|
THVD2412V
|
SMD/SMT
|
SOIC-14
|
Transceiver
|
1 Driver
|
1 Receiver
|
250 kb/s, 1 Mb/s
|
5.5 V
|
3 V
|
- 40 C
|
+ 125 C
|
Reel, Cut Tape, MouseReel
|
|
|
|
RS-422/RS-485 Interface IC 3V-to-5.5V 250Kbps R S-485 transceiver w
- THVD2419DRCR
- Texas Instruments
-
1:
$8.42
-
4,785In Stock
-
New Product
|
Mouser Part No
595-THVD2419DRCR
New Product
|
Texas Instruments
|
RS-422/RS-485 Interface IC 3V-to-5.5V 250Kbps R S-485 transceiver w
|
|
4,785In Stock
|
|
|
$8.42
|
|
|
$5.79
|
|
|
$5.39
|
|
|
$4.75
|
|
|
View
|
|
|
$3.20
|
|
|
$4.50
|
|
|
$4.05
|
|
|
$3.40
|
|
|
$3.29
|
|
|
$3.20
|
|
Min.: 1
Mult.: 1
|
|
|
THVD2419
|
SMD/SMT
|
VSON-10
|
Transceiver
|
1 Driver
|
1 Receiver
|
|
5.5 V
|
3 V
|
- 40 C
|
+ 125 C
|
Reel, Cut Tape
|
|
|
|
RS-422/RS-485 Interface IC 3V-to-5.5V 20Mbps RS -485 transceiver wi
- THVD2429DRCR
- Texas Instruments
-
1:
$8.42
-
3,065In Stock
-
New Product
|
Mouser Part No
595-THVD2429DRCR
New Product
|
Texas Instruments
|
RS-422/RS-485 Interface IC 3V-to-5.5V 20Mbps RS -485 transceiver wi
|
|
3,065In Stock
|
|
|
$8.42
|
|
|
$5.79
|
|
|
$5.39
|
|
|
$4.75
|
|
|
View
|
|
|
$3.20
|
|
|
$4.50
|
|
|
$4.05
|
|
|
$3.40
|
|
|
$3.29
|
|
|
$3.20
|
|
Min.: 1
Mult.: 1
|
|
|
THVD2429
|
|
|
|
|
|
|
|
|
|
|
Reel, Cut Tape
|
|
|
|
RS-422/RS-485 Interface IC 3.3-V to 5-V 20-Mbp s full-duplex RS-48
- THVD2442DRCR
- Texas Instruments
-
1:
$6.21
-
3,167In Stock
-
New Product
|
Mouser Part No
595-THVD2442DRCR
New Product
|
Texas Instruments
|
RS-422/RS-485 Interface IC 3.3-V to 5-V 20-Mbp s full-duplex RS-48
|
|
3,167In Stock
|
|
|
$6.21
|
|
|
$4.72
|
|
|
$4.33
|
|
|
$3.92
|
|
|
View
|
|
|
$3.33
|
|
|
$3.73
|
|
|
$3.60
|
|
|
$3.52
|
|
|
$3.47
|
|
|
$3.33
|
|
Min.: 1
Mult.: 1
|
|
|
THVD2442
|
SMD/SMT
|
VSON-10
|
Transceiver
|
1 Driver
|
1 Receiver
|
20 Mb/s
|
5.5 V
|
3 V
|
- 40 C
|
+ 125 C
|
Reel, Cut Tape, MouseReel
|
|
|
|
RS-422/RS-485 Interface IC 3-V to 5.5-V 50-Mbp s full-duplex RS-48
- THVD2452VDR
- Texas Instruments
-
1:
$7.54
-
2,939In Stock
-
2,500On Order
-
New Product
|
Mouser Part No
595-THVD2452VDR
New Product
|
Texas Instruments
|
RS-422/RS-485 Interface IC 3-V to 5.5-V 50-Mbp s full-duplex RS-48
|
|
2,939In Stock
2,500On Order
|
|
|
$7.54
|
|
|
$5.76
|
|
|
$5.31
|
|
|
$4.82
|
|
|
View
|
|
|
$4.29
|
|
|
$4.59
|
|
|
$4.45
|
|
|
$4.33
|
|
|
$4.29
|
|
|
Quote
|
|
Min.: 1
Mult.: 1
|
|
|
THVD2452V
|
SMD/SMT
|
SOIC-14
|
Transceiver
|
1 Driver
|
1 Receiver
|
20 Mb/s, 50 Mb/s
|
5.5 V
|
3 V
|
- 40 C
|
+ 125 C
|
Reel, Cut Tape, MouseReel
|
|
|
|
RS-422/RS-485 Interface IC 70-V bus-fault prote cted flexible IO 3
- THVD2450VDRCR
- Texas Instruments
-
1:
$6.36
-
11,677In Stock
|
Mouser Part No
595-THVD2450VDRCR
|
Texas Instruments
|
RS-422/RS-485 Interface IC 70-V bus-fault prote cted flexible IO 3
|
|
11,677In Stock
|
|
|
$6.36
|
|
|
$4.83
|
|
|
$4.45
|
|
|
$4.03
|
|
|
View
|
|
|
$3.50
|
|
|
$3.68
|
|
|
$3.58
|
|
|
$3.50
|
|
Min.: 1
Mult.: 1
|
|
|
THVD2450V
|
SMD/SMT
|
VSON-10
|
Transceiver
|
1 Driver
|
1 Receiver
|
20 Mb/s
|
5.5 V
|
3 V
|
- 40 C
|
+ 125 C
|
Reel, Cut Tape, MouseReel
|
|
|
|
RS-422/RS-485 Interface IC THVD4431RHAR
- THVD4431RHAR
- Texas Instruments
-
1:
$13.33
-
3,193In Stock
|
Mouser Part No
595-THVD4431RHAR
|
Texas Instruments
|
RS-422/RS-485 Interface IC THVD4431RHAR
|
|
3,193In Stock
|
|
|
$13.33
|
|
|
$10.38
|
|
|
$9.65
|
|
|
$8.84
|
|
|
View
|
|
|
$7.72
|
|
|
$8.45
|
|
|
$8.21
|
|
|
$8.02
|
|
|
$7.82
|
|
|
$7.72
|
|
Min.: 1
Mult.: 1
|
|
|
THVD4431
|
SMD/SMT
|
VQFN-40
|
Transceiver
|
|
6 Receiver
|
20 Mb/s
|
5.5 V
|
3 V
|
- 40 C
|
+ 125 C
|
Reel, Cut Tape
|
|
|
|
RS-422/RS-485 Interface IC 3-V to 5.5-V 1-Mbps half-duplex RS-485
- THVD2410VDRCR
- Texas Instruments
-
1:
$6.36
-
726In Stock
|
Mouser Part No
595-THVD2410VDRCR
|
Texas Instruments
|
RS-422/RS-485 Interface IC 3-V to 5.5-V 1-Mbps half-duplex RS-485
|
|
726In Stock
|
|
|
$6.36
|
|
|
$4.83
|
|
|
$4.45
|
|
|
$4.03
|
|
|
View
|
|
|
$3.42
|
|
|
$3.95
|
|
|
$3.78
|
|
|
$3.70
|
|
|
$3.42
|
|
Min.: 1
Mult.: 1
|
|
|
THVD2410V
|
SMD/SMT
|
VSON-10
|
Transceiver
|
1 Driver
|
1 Receiver
|
1 Mb/s
|
5.5 V
|
3 V
|
- 40 C
|
+ 125 C
|
Reel, Cut Tape, MouseReel
|
|
|
|
RS-422/RS-485 Interface IC EMC protected 50-Mb ps half-duplex 5-k A A 595-ISO1450DWR
- ISO1450DW
- Texas Instruments
-
1:
$9.15
-
7,929In Stock
|
Mouser Part No
595-ISO1450DW
|
Texas Instruments
|
RS-422/RS-485 Interface IC EMC protected 50-Mb ps half-duplex 5-k A A 595-ISO1450DWR
|
|
7,929In Stock
|
|
|
$9.15
|
|
|
$7.04
|
|
|
$6.29
|
|
|
$6.28
|
|
|
View
|
|
|
$6.03
|
|
|
$5.45
|
|
|
$5.31
|
|
Min.: 1
Mult.: 1
|
|
|
ISO1450
|
SMD/SMT
|
SOIC-16
|
Transceiver
|
1 Driver
|
1 Receiver
|
50 Mb/s
|
5.5 V
|
1.71 V
|
- 40 C
|
+ 125 C
|
Tube
|
|
|
|
RS-422/RS-485 Interface IC 70V Fault-Prot RS485 Transceivers A 595- A 595-SN65HVD1785DR
- SN65HVD1785D
- Texas Instruments
-
1:
$8.35
-
4,637In Stock
|
Mouser Part No
595-SN65HVD1785D
|
Texas Instruments
|
RS-422/RS-485 Interface IC 70V Fault-Prot RS485 Transceivers A 595- A 595-SN65HVD1785DR
|
|
4,637In Stock
|
|
|
$8.35
|
|
|
$6.41
|
|
|
$5.48
|
|
|
$5.23
|
|
|
View
|
|
|
$5.06
|
|
|
$4.95
|
|
|
$4.82
|
|
|
$4.79
|
|
|
Quote
|
|
Min.: 1
Mult.: 1
|
|
|
SN65HVD1785
|
SMD/SMT
|
SOIC-8
|
Transceiver
|
1 Driver
|
1 Receiver
|
115 kb/s
|
5.5 V
|
4.5 V
|
- 40 C
|
+ 105 C
|
Tube
|
|
|
|
RS-422/RS-485 Interface IC Hi-Output Full-dplx Driver and Receiver A 595-SN65HVD53D
- SN65HVD53DR
- Texas Instruments
-
1:
$6.01
-
11,235In Stock
|
Mouser Part No
595-SN65HVD53DR
|
Texas Instruments
|
RS-422/RS-485 Interface IC Hi-Output Full-dplx Driver and Receiver A 595-SN65HVD53D
|
|
11,235In Stock
|
|
|
$6.01
|
|
|
$4.56
|
|
|
$4.19
|
|
|
$3.79
|
|
|
View
|
|
|
$3.27
|
|
|
$3.60
|
|
|
$3.49
|
|
|
$3.39
|
|
|
$3.27
|
|
Min.: 1
Mult.: 1
|
|
|
SN65HVD53
|
SMD/SMT
|
SOIC-14
|
Transceiver
|
1 Driver
|
1 Receiver
|
25 Mb/s
|
5 V
|
5 V
|
- 40 C
|
+ 85 C
|
Reel, Cut Tape, MouseReel
|
|
|
|
RS-422/RS-485 Interface IC Hi-Output Full-dplx Driver and Receiver A 595-SN65HVD55D
- SN65HVD55DR
- Texas Instruments
-
1:
$6.01
-
15,100In Stock
|
Mouser Part No
595-SN65HVD55DR
|
Texas Instruments
|
RS-422/RS-485 Interface IC Hi-Output Full-dplx Driver and Receiver A 595-SN65HVD55D
|
|
15,100In Stock
|
|
|
$6.01
|
|
|
$4.56
|
|
|
$4.19
|
|
|
$3.79
|
|
|
$3.27
|
|
|
View
|
|
|
$3.60
|
|
|
$3.49
|
|
|
$3.39
|
|
|
$3.26
|
|
Min.: 1
Mult.: 1
|
|
|
SN65HVD55
|
SMD/SMT
|
SOIC-14
|
Transceiver
|
1 Driver
|
1 Receiver
|
1 Mb/s
|
5 V
|
5 V
|
- 40 C
|
+ 85 C
|
Reel, Cut Tape, MouseReel
|
|
|
|
RS-422/RS-485 Interface IC Quad RS-485 Diff Lin e Driver A 595-SN65 A 595-SN65LBC174ADW
- SN65LBC174ADWR
- Texas Instruments
-
1:
$14.67
-
2,896In Stock
|
Mouser Part No
595-SN65LBC174ADWR
|
Texas Instruments
|
RS-422/RS-485 Interface IC Quad RS-485 Diff Lin e Driver A 595-SN65 A 595-SN65LBC174ADW
|
|
2,896In Stock
|
|
|
$14.67
|
|
|
$11.34
|
|
|
$10.81
|
|
|
$9.40
|
|
|
View
|
|
|
$7.19
|
|
|
$8.97
|
|
|
$8.18
|
|
|
$7.19
|
|
|
$7.19
|
|
|
Quote
|
|
Min.: 1
Mult.: 1
|
|
|
SN65LBC174A
|
SMD/SMT
|
SOIC-20
|
Driver
|
4 Driver
|
0 Receiver
|
30 Mb/s
|
5 V
|
5 V
|
- 40 C
|
+ 85 C
|
Reel, Cut Tape, MouseReel
|
|
|
|
RS-422/RS-485 Interface IC 3.3-V to 5-V 500-Kb ps RS-485 transceiv
- THVD1400DR
- Texas Instruments
-
1:
$1.13
-
46,162In Stock
-
47,500On Order
|
Mouser Part No
595-THVD1400DR
|
Texas Instruments
|
RS-422/RS-485 Interface IC 3.3-V to 5-V 500-Kb ps RS-485 transceiv
|
|
46,162In Stock
47,500On Order
|
|
|
$1.13
|
|
|
$0.804
|
|
|
$0.724
|
|
|
$0.633
|
|
|
$0.522
|
|
|
View
|
|
|
$0.592
|
|
|
$0.566
|
|
|
$0.545
|
|
|
$0.508
|
|
Min.: 1
Mult.: 1
|
|
|
THVD1400
|
SMD/SMT
|
SOIC-8
|
Transceiver
|
1 Driver
|
1 Receiver
|
500 kb/s
|
5.5 V
|
3 V
|
- 40 C
|
+ 125 C
|
Reel, Cut Tape, MouseReel
|
|
|
|
RS-422/RS-485 Interface IC Quadruple Differenti al Line Receiver 16
- AM26C32IDBR
- Texas Instruments
-
1:
$5.25
-
1,184In Stock
|
Mouser Part No
595-AM26C32IDBR
|
Texas Instruments
|
RS-422/RS-485 Interface IC Quadruple Differenti al Line Receiver 16
|
|
1,184In Stock
|
|
|
$5.25
|
|
|
$3.56
|
|
|
$3.29
|
|
|
$2.86
|
|
|
View
|
|
|
$2.69
|
|
|
$2.35
|
|
|
$1.94
|
|
|
$1.83
|
|
Min.: 1
Mult.: 1
|
|
|
AM26C32
|
SMD/SMT
|
SSOP-16
|
Receiver
|
|
4 Receiver
|
|
5.5 V
|
4.5 V
|
- 40 C
|
+ 85 C
|
|
|
|
|
RS-422/RS-485 Interface IC Mil Enhance Quad RS- 485 Diff Line Drvr
- SN65LBC174AMDWREP
- Texas Instruments
-
1:
$25.07
-
2,112In Stock
|
Mouser Part No
595-S65LBC174AMDWREP
|
Texas Instruments
|
RS-422/RS-485 Interface IC Mil Enhance Quad RS- 485 Diff Line Drvr
|
|
2,112In Stock
|
|
|
$25.07
|
|
|
$19.93
|
|
|
$18.65
|
|
|
$17.23
|
|
|
View
|
|
|
$15.86
|
|
|
$16.56
|
|
|
$16.16
|
|
|
$15.99
|
|
|
$15.86
|
|
|
Quote
|
|
Min.: 1
Mult.: 1
|
|
|
SN65LBC174A
|
SMD/SMT
|
SOIC-20
|
Driver
|
4 Driver
|
0 Receiver
|
30 Mb/s
|
5 V
|
5 V
|
- 55 C
|
+ 125 C
|
Reel, Cut Tape, MouseReel
|
|
Singapore