3

Electrical characteristics

Table 4. Operating conditions

Symbol

Parameter

Min.

Typ.

Max.

Unit

VCC

Device supply voltage

3

5.5

V

VI

Input level at any bus terminal (separated or common-mode)

-7

12

V

VID

Differential input voltage

-7

12

V

IO

Output current/driver

-70

70

mA

Output current/receiver

-70

70

RL

Differential load resistance

54

60

Ω

CL

Differential load capacitance

50

pF

DR

Signaling rate for ST4E1216

16

Mbps

Signaling rate for ST4E1240

40

TA

Operating free-air temperature for ST4E1216

-40

125

°C

Operating free-air temperature for ST4E1240

-40

85

Operation is specified for internal (junction temperature) up to 150 °C. Self-heating due to internal power

dissipation should be considered for each application. Maximum junction temperature is internally limited by the

thermal shutdown circuit, which disables the driver outputs when the junction temperature reaches 165 °C.

Table 5. Thermal information

Symbol

Parameter

Min.

Typ.

Max.

Unit

Rth-ja

Thermal resistance, junction-to-ambient

125

°C/W

Table 6. Power dissipation

Symbol

Parameter

Test conditions

Typ.

Unit

PD

ST4E1240 power dissipation, with

driver and receiver enabled

VCC = 5.5 V, T = 85 °C, 50% duty

cycle at 40 Mbps signaling rate

Unterminated, RL = 300 Ω, CL = 50 pF

310

mW

RS485-load: RL = 54 Ω, CL = 50 pF

370

mW

ST4E1216 power dissipation, with

driver and receiver enabled

VCC = 5.5 V, T = 125 °C, 50% duty

cycle at 16 Mbps signaling rate

Unterminated, RL = 300 Ω, CL = 50 pF

140

mW

RS485-load: RL = 54 Ω, CL = 50 pF

220

mW

ST4E1216, ST4E1240

Electrical characteristics

DS14542 - Rev 2

page 4/31