Datasheet LT1711, LT1712 (Analog Devices) - 9
| Fabricante | Analog Devices |
| Descripción | Single/Dual 4.5ns, 3V/5V/±5V, Rail-to-Rail Comparators |
| Páginas / Página | 12 / 9 — APPLICATIO S I FOR ATIO. Figure 2. Various Configurations for Introducing … |
| Formato / tamaño de archivo | PDF / 226 Kb |
| Idioma del documento | Inglés |
APPLICATIO S I FOR ATIO. Figure 2. Various Configurations for Introducing Hysteresis. TYPICAL APPLICATIO S
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LT1711/LT1712
U U W U APPLICATIO S I FOR ATIO
100k Q 50k VIN + Q Q 50Ω 50Ω LT1711 V + IN + VIN + – LT1711 LT1711 50Ω – Q VREF – VIN – 50k V+ = 5V Q Q V– = –5V 50Ω VHYST = 5mV 100k (ALL 3 CASES) 171112 F02
Figure 2. Various Configurations for Introducing Hysteresis U TYPICAL APPLICATIO S Simultaneous Full Duplex 75Mbaud Interface
with a full ±3V (one whole VS up or down) of ground
with Only Two Wires
potential difference. The circuit of Figure 3 shows a simple, fully bidirectional, The circuit works well with the resistor values shown, but differential 2-wire interface that gives good results to other sets of values can be used. The starting point is the 75Mbaud, using the LT1712. Eye diagrams under condi- characteristic impedance, ZO, of the twisted-pair cable. tions of unidirectional and bidirectional communication The input impedance of the resistive network should are shown in Figures 4 and 5. Although not as pristine as match the characteristic impedance and is given by: the unidirectional performance of Figure␣ 4, the perfor- mance under simultaneous bidirectional operation is still R1|| R ( 2 R3) R = + 2 • R IN O • excellent. Because the LT1712 input voltage range ex- R + 2 • R [ 1|| R(2+R3 ] O ) tends 100mV beyond both supply rails, the circuit works 750k 750k 3V 3V 4 2 2 4 14 + + 14 1/2 1/2 RxD RxD LT1712 LE LT1712 1 1 LE 13 16 – – 16 13 3 15 15 3 750k 750k 3V 3V 100k 100k 3V R2A R1C R1A R2C 3V 499 499Ω Ω 49.9Ω 2.55k 2.55k 7 5 5 7 49.9Ω + 11 11 + 1/2 R3A R R R3C 1/2 TxD OA OB TxD 49.9 LT1712 Ω 124Ω 140Ω 140Ω 124Ω LT1712 8 8 49.9Ω – LE 12 10 12 LE – 6-FEET 6 6 10 R1D 9 R3B R1B TWISTED PAIR R3D 124Ω 499Ω Z 9 O ≈ 120Ω 499Ω 124Ω R2B DIODES: BAV99 R2D 100k 2.55k ×4 2.55k 100k 171112 F03
Figure 3. 75Mbaud Full Duplex Interface on Two Wires
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U U W U APPLICATIO S I FOR ATIO
100k Q 50k VIN + Q Q 50Ω 50Ω LT1711 V + IN + VIN + – LT1711 LT1711 50Ω – Q VREF – VIN – 50k V+ = 5V Q Q V– = –5V 50Ω VHYST = 5mV 100k (ALL 3 CASES) 171112 F02
Figure 2. Various Configurations for Introducing Hysteresis U TYPICAL APPLICATIO S Simultaneous Full Duplex 75Mbaud Interface
with a full ±3V (one whole VS up or down) of ground
with Only Two Wires
potential difference. The circuit of Figure 3 shows a simple, fully bidirectional, The circuit works well with the resistor values shown, but differential 2-wire interface that gives good results to other sets of values can be used. The starting point is the 75Mbaud, using the LT1712. Eye diagrams under condi- characteristic impedance, ZO, of the twisted-pair cable. tions of unidirectional and bidirectional communication The input impedance of the resistive network should are shown in Figures 4 and 5. Although not as pristine as match the characteristic impedance and is given by: the unidirectional performance of Figure␣ 4, the perfor- mance under simultaneous bidirectional operation is still R1|| R ( 2 R3) R = + 2 • R IN O • excellent. Because the LT1712 input voltage range ex- R + 2 • R [ 1|| R(2+R3 ] O ) tends 100mV beyond both supply rails, the circuit works 750k 750k 3V 3V 4 2 2 4 14 + + 14 1/2 1/2 RxD RxD LT1712 LE LT1712 1 1 LE 13 16 – – 16 13 3 15 15 3 750k 750k 3V 3V 100k 100k 3V R2A R1C R1A R2C 3V 499 499Ω Ω 49.9Ω 2.55k 2.55k 7 5 5 7 49.9Ω + 11 11 + 1/2 R3A R R R3C 1/2 TxD OA OB TxD 49.9 LT1712 Ω 124Ω 140Ω 140Ω 124Ω LT1712 8 8 49.9Ω – LE 12 10 12 LE – 6-FEET 6 6 10 R1D 9 R3B R1B TWISTED PAIR R3D 124Ω 499Ω Z 9 O ≈ 120Ω 499Ω 124Ω R2B DIODES: BAV99 R2D 100k 2.55k ×4 2.55k 100k 171112 F03
Figure 3. 75Mbaud Full Duplex Interface on Two Wires
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