ISL33334E, ISL33337E

3

FN8776.1

October 21, 2016

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Pin Descriptions

PIN NAME

PIN # for

SSOP

PIN # for

QFN

PORT/

MODE

FUNCTION

NC

-

32, 33, 39,

40

BOTH

No Internal Connection.

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.

26

31, 34

BOTH

GND

15

15, 16

BOTH

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).

9

12, 20, 7,

14, 26

BOTH

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 (+5.5V).

V-

17

19

1 / RS-232 Internally generated negative RS-232 transmitter supply (-5.5V).

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).

SLOW485

14

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.

TABLE 3. ISL33334E AND ISL33337E FUNCTION TABLE

INPUTS

RECEIVER OUTPUTS

DRIVER OUTPUTS

CHARGE

PUMPS

(Note 4)

DRIVER

DATA

RATE

(bps)

MODE

PORT

SHDN

RE485

DE485

SLOW485

RO

R1OUT

AND

R2OUT

Y AND Z

T1OUT AND

T2OUT

1

1

N.A.

N.A.

N.A.

N.A.

ON

N.A.

ON

ON

400k

RS-232