4 Pin Configuration and Functions

Figure 4-1 40-Pin VQFN Package (RHA)
Top View

Table 4-1 Pin Functions

NAME	NO.	TYPE	DESCRIPTION
L1	1	O	Logic output (RS-232)
L2	2	O	Logic output (RS-232/RS-485)
L3	3	I	Logic input (RS-232/RS-485). Integrated weak pull-up resistor .
L4	4	I	Logic input. Integrated weak pull-up resistor
L5	5	O	Logic output
L6	6	I	Logic input, Integrated weak pull-up resistor
L7	7	O	Logic output
L8	8	O	Logic output
V_IO	9	P	1.65 V to 5.5 V logic supply voltage
GND⁽¹⁾	10	G	Ground
SLR	11	I	Slew rate control, internal pull-down resistor. SLR=H enables slow speed
DIR	12	I	RS-485 TX/RX enable/disable. Internal pull-down resistor.
MODE2	13	I	MODE control pins, Integrated weak pull-down resistor
MODE0	14	I
MODE1	15	I
NC	16	NC	Not connected internally. Can be connected to supply, ground or left open on PCB.
TERM_TX	17	I	120 Ω Termination enable/disable across R1/R2 terminals. Internal Pull down resistor
TERM_RX	18	I	120 Ω Termination enable/disable across R3/R4 terminals. Internal Pull down resistor
SHDN	19	I	Device enable/disable. Internal pull-down resistor
V_CC	20	P	3 to 5.5V supply voltage
R8	21	I	RS-232 receiver input
R7	22	I	RS-232 receiver input
GND⁽¹⁾	23	G	Ground
R6	24	O	RS-232 driver output
R5	25	I	RS-232 receiver input
GND	26	G	Ground
R4	27	I/O	RS-232 driver output or RS-485 inverting receiver input (B)
R3	28	I/O	RS-232 driver output or RS-485 non-inverting receiver input (A)
GND⁽¹⁾	29	G	Ground
R2	30	I/O	RS-232 receiver input or RS-485 bus pin (Y or A)
R1	31	I/O	RS-232 receiver input or RS-485 bus pin (Z or B)
V_CC	32	P	3 to 5.5 V supply voltage
V-	33		Negative charge pump rail
C2-	34		Negative terminal of charge pump capacitor
C1-	35		Negative terminal of charge pump capacitor
NC	36	NC	Not connected internally. Can be left open or Grounded on PCB.
C1+	37		Positive terminal of charge pump capacitor
V_CC	38	P	3 to 5.5V supply voltage
C2+	39		Positive terminal of charge pump capacitor
V+	40		Positive charge pump rail

(1) GND pins 10, 23, 26, 29 all must be grounded on PCB.