MAX13170E
+5V Multiprotocol, 3Tx/3Rx, Software-
Selectable Clock/Data Transceiver
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Detailed Description
The MAX13170E is a three-driver/three-receiver, multi-
protocol transceiver that operates from a single +5V
supply. The MAX13170E, along with the MAX13172E
and MAX13174E, form a complete software-selectable
DTE or DCE interface port that supports the V.28 (RS-
232), V.10/V.11 (RS-449/V.36, EIA-530, EIA-530A,
X.21), and V.35 protocols. The MAX13170E trans-
ceivers carry the high-speed clock and data signals,
while the MAX13172E transceivers carry serial-interface
control signaling. The MAX13170E can be terminated
by the MAX13174E software-selectable resistor termi-
nation network or by a discrete termination network.
The MAX13170E features a 0.5µA no-cable mode, fail-
safe operation, and thermal shutdown circuitry. Thermal
shutdown protects the drivers against excessive power
dissipation. When activated, the thermal shutdown cir-
cuitry places the receiver and transmitter outputs into a
high-impedance state.
Mode Selection
The state of the mode-select inputs M0, M1, and M2
determines which serial interface protocol is selected
(Table 1). The state of the DCE/DTE input determines
whether the transceiver is configured as a DTE or DCE
serial port. When the DCE/DTE input is logic-high, dri-
ver T3 is activated and receiver R1 is disabled. When
the DCE/DTE input is logic-low, driver T3 is disabled
and receiver R1 is activated (Table 1). M0, M1, M2, and
DCE/DTE are internally pulled up to V
CC
to ensure a
logic-high if left unconnected.
No-Cable Mode
The MAX13170E enters no-cable mode when the
mode-select inputs are left unconnected or connected
high (M0 = M1 = M2 = 1). In this mode, the multiproto-
col drivers and receivers are disabled and the supply
current drops to 0.5µA. The receivers’ outputs enter a
high-impedance state in no-cable mode, allowing these
output lines to be shared with other receivers’ outputs,
(the receivers’ outputs have internal pullup resistors to
pull the outputs high if not driven). Also, in no-cable
mode, the transmitter outputs enter a high-impedance
state so that these output lines can be shared with
other devices.
Dual Charge-Pump Voltage Converter
The MAX13170E internal power supply consists of a reg-
ulated dual charge pump that provides positive and
negative output voltages from a +5V supply. The charge
pump operates in discontinuous mode. If the output volt-
age is less than the regulated voltage, the charge pump
is enabled. If the output voltage exceeds the regulated
voltage, the charge pump is disabled. Each charge
pump requires a flying capacitor (C1, C2) and a reser-
voir capacitor (C3, C5) to generate the V
DD
and V
EE
supplies. Figure 10 shows charge-pump connections.
