MAX3170 Просмотр технического описания (PDF) - Maxim Integrated
Номер в каталоге
Компоненты Описание
производитель
MAX3170 Datasheet PDF : 16 Pages
| |||
+3.3V, Multiprotocol, 3 Tx/3 Rx, Software-
Selectable Clock/Data Transceiver
CTS(DTE)
RTS(DCE)
DSR(DTE)
DTR(DCE)
DTR(DTE)
DSR(DCE)
DCD(DTE) RTS(DTE)
DCD(DCE) CTS(DCE)
MAX3171 R3 R2 R1
MAX3173
D3 D2 D1
MAX3172
MAX3174
R4
D4
RXD(DTE)
TXD(DCE)
RXC(DTE)
SCTE(DCE)
SCTE(DTE)
RXC(DCE)
TXC(DTE) TXD(DTE)
TXC(DCE) RXD(DCE)
R3 R2 R1
D3 D2 D1
MAX3170
M0 M1 M2 DCE/DTE
13 5 10 8
VCC
22 6 23 20 19 4
1
7 18 21
M0 M1
25
DCE/DTE
DB-25 CONNECTOR
16 3 9 17
12 15 11 24 14 2
CABLE WIRING FOR
MODE SELECTION
MODE
PIN 18 PIN 21
V.35
PIN 7 PIN 7
RS-449, V.36 N.C. PIN 7
RS-232
PIN 7 N.C.
NO CABLE N.C. N.C.
CABLE WIRING FOR
DCE/DTE SELECTION
MODE
PIN 25
DTE
PIN 7
DCE
N.C.
Figure 7. Cable-Selectable Multiprotocol DCE/DTE Port
In Figure 12, the MAX3172 or MAX3174 is used to
implement the resistive T-network that is needed to
properly terminate the V.35 driver and receiver. Internal
to the MAX3172/MAX3174, S1 and S2 are closed to
connect the T-network resistors to the circuit. The V.28
termination resistor (internal to the MAX3170) is dis-
abled by opening S3 to avoid interference with the T-
network impedances.
V.28 Interface
The V.28 interface is an unbalanced single-ended inter-
face (Figure 13). The V.28 driver generates a minimum
of ±5V across the load impedance between A′ and C′.
The V.28 receiver has a single-ended input and does
not reject any common-mode differences between C
and C′. The V.28 receiver has input trip points at ±3V.
To aid in rejecting system noise, the MAX3170 V.28
receiver has a typical hysteresis of 0.5V.
Figure 14 shows that the MAX3172/MAX3174 termina-
tion network is disabled by opening S1 and S2. The
MAX3170’s internal 5kΩ V.28 termination is enabled by
closing S3.
______________________________________________________________________________________ 11
Share Link: 