ISL3330_14 Datasheet, PDF (5/25 Pages) Intersil Corporation – 3.3V, ±15kV ESD Protected, Dual Protocol (RS-232/RS-485) Transceivers

ISL3330, ISL3331
Pin Descriptions
PIN
MODE
FUNCTION
485/232 BOTH Interface Mode Select input. High for RS-485 Mode and low for RS-232 Mode.
DEN
BOTH Driver output enable. The driver outputs, Y and Z, are enabled by bringing DEN high. They are high impedance when DEN
is low.
GND BOTH Ground connection.
NC BOTH No Connection.
ON BOTH In RS-232 mode only, ON high enables the charge pumps. ON low, with DEN and RXEN low (and RXEN high if QFN), turns
off the charge pumps (in RS-232 mode), and in either mode places the device in low power shutdown. In both modes, when
ON is low, and DEN is high, and RXEN is high or RXEN is low, loopback is enabled.
RXEN BOTH Receiver output enable. Rx is enabled when RXEN is high; Rx is high impedance when RXEN is low and, if using the QFN
package, RXEN is high. When using the QFN and the active high Rx enable function, RXEN should be high or floating.
RXEN
BOTH
Active low receiver output enable. Rx is enabled when RXEN is low; Rx is high impedance when RXEN is high and RXEN
is low. (i.e., to use active low Rx enable function, tie RXEN to GND). For single signal Tx/Rx direction control, connect RXEN
to DEN. Internally pulled high. (QFN only)
V_CC
V_L
A
BOTH System power supply input (3.3V).
BOTH Logic-Level Supply. All TTL/CMOS inputs and outputs are powered by this supply. QFN logic input pins that are externally
tied high in an application, should use the V_L supply for the high voltage level. (QFN only)
RS-232 Receiver input with ±15kV ESD protection. A low on A forces R_A high; A high on A forces R_A low.
RS-485 Inverting receiver input with ±15kV ESD protection.
B
RS-232 Receiver input with ±15kV ESD protection. A low on B forces R_B high; A high on B forces R_B low.
RS-485 Noninverting receiver input with ±15kV ESD protection.
D_Y
RS-232 Driver input. A low on D_Y forces output Y high. Similarly, a high on D_Y forces output Y low.
RS-485 Driver input. A low on D_Y forces output Y high and output Z low. Similarly, a high on D_Y forces output Y low and output Z high.
D_Z/SLEW RS-232 Driver input. A low on D_Z forces output Z high. Similarly, a high on D_Z forces output Z low.
RS-485 Slew rate control. With the SLEW pin high, the drivers run at the maximum slew rate (20Mbps). With the SLEW pin low, the
drivers run at a reduced slew rate (460kbps). The QFN version works in conjunction with SPB to select one of three RS-485
data rates. Internally pulled high in RS-485 mode.
SPB
RS-485 Speed control. Works in conjunction with the SLEW pin to select the 20Mbps, 460kbps or 115kbps RS-485 data rate.
Internally pulled high. (QFN only)
R_A
RS-232 Receiver output.
RS-485 Receiver output: If B > A by at least -40mV, R_A is high; If B < A by -200mV or more, R_A is low; R_A = High if A and B are
unconnected (floating) or shorted together (i.e., full fail-safe).
R_B
RS-232 Receiver output.
RS-485 Not used. Output is high impedance, and unaffected by RXEN and RXEN.
Y
RS-232 Driver output with ±15kV ESD protection.
RS-485 Inverting driver output with ±15kV ESD protection.
Z
RS-232 Driver output with ±15kV ESD protection.
RS-485 Noninverting driver output with ±15kV ESD protection.
C1+ RS-232 External capacitor (voltage doubler) is connected to this lead. Not needed in RS-485 Mode.
C1- RS-232 External capacitor (voltage doubler) is connected to this lead. Not needed in RS-485 Mode.
C2+ RS-232 External capacitor (voltage inverter) is connected to this lead. Not needed in RS-485 Mode.
C2- RS-232 External capacitor (voltage inverter) is connected to this lead. Not needed in RS-485 Mode.
V+ RS-232 Internally generated positive RS-232 transmitter supply (+5.5V). C3 not needed in RS-485 Mode.
V-
RS-232 Internally generated negative RS-232 transmitter supply (-5.5V). C4 not needed in RS-485 Mode.
5
FN6361.0
May 20, 2008