ISL33354E Datasheet, PDF (3/23 Pages) Intersil Corporation – Full fail-safe (open/short) RS-485/422 port 2 Rx

ISL33354E, ISL33357E
Pin Descriptions
PIN #
for
PIN NAME SSOP
PIN # for
QFN PORT/MODE
FUNCTION
NC
- 12, 20, 32, BOTH No Internal Connection.
33, 39, 40
DNC
-
21
BOTH Do not make any external connections to this pin.
SHDN
21
25
BOTH
A low on SHDN disables the charge pumps, disables all the outputs and places the device in low power
shutdown. Internally pulled-high. SHDN = 1 for normal operation.
V_CC
26
31, 34
GND
15
15, 16
BOTH
BOTH
System power supply input (4.5V to 5.5V). Both pins 31 and 34 must connect to the V_CC supply.
Ground connection. QFN pins 15 and 16 must both connect to GND. This is also the potential of the
QFN’s exposed metal pad (EP).
*V_CC
9
7, 14, 26
BOTH For proper operation, connect this lead to the V_CC supply. This is not a power supply lead, so no decoupling
is required.
*GND
8
6, 17
BOTH For proper operation, connect this lead to GND. This is not a power supply lead.
RxIN
4, 5
2, 3 1 / RS-232 RS-232 receiver input with ±15kV ESD protection. A low on RxIN forces RxOUT high; a high on RxIN
forces RxOUT low.
RxOUT 24, 25 29, 30 1 / RS-232 RS-232 receiver output.
TxIN 22, 23 27, 28 1 / RS-232 RS-232 transmitter input. A low on TxIN drives the corresponding TxOUT high, while a high on TxIN drives
the corresponding TxOUT low.
TxOUT 6, 7
4, 5 1 / RS-232 RS-232 transmitter output with ±15kV ESD protection.
C1+
1
37
1 / RS-232 External charge pump capacitor is connected to this lead.
C1-
2
38
1 / RS-232 External charge pump capacitor is connected to this lead.
C2+
28
36
1 / RS-232 External charge pump capacitor is connected to this lead.
C2-
27
35
1 / RS-232 External charge pump capacitor is connected to this lead.
V+
3
1
1 / RS-232 Internally generated positive RS-232 transmitter supply (+6V).
V-
17
19
1 / RS-232 Internally generated negative RS-232 transmitter supply (-7V).
A
12
10
2 / RS-485 RS-485 noninverting receiver input with ±15kV ESD protection.
B
13
11
2 / RS-485 RS-485 inverting receiver input with ±15kV ESD protection.
Y
10
8
2/ RS-485 RS-485 noninverting driver output with ±15kV ESD protection.
Z
11
9
2/ RS-485 RS-485 inverting driver output with ±15kV ESD protection.
DI
20
24
2 / RS-485 RS-485 driver input. A low on DI forces output Y low and output Z high.
RO
18
22
2 / RS-485 RS-485 receiver output: If A > B by at least -40mV, RO is high; If A < B by -200mV or more, RO is low;
RO = High if A and B are unconnected (floating) or shorted together (i.e., full fail-safe).
SLOW48 14
5
13
2 / RS-485 RS-485 data rate control. A low on SLOW485 selects the 115kbps RS-485 data rate (slew rate limited
output transitions); a high selects the 20Mbps data rate (full speed transitions). Internally pulled-high.
RE485 16
18
2/ RS-485 RS-485 active low receiver output enable. RO is enabled when RE485 is low; RO is high impedance
when RE485 is high. Internally pulled low.
DE485 19
23
2/ RS-485 RS-485 driver output enable (DE). The driver outputs, Y and Z, are enabled by driving DE485 high. They
are high impedance when DE485 is low. Internally pulled high.
EP
-
EP
BOTH QFN exposed thermal pad (EPAD). Connect to GND.
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FN8775.1
October 21, 2016