TUSB2040A

4-PORT HUB FOR THE UNIVERSAL SERIAL BUS

WITH OPTIONAL SERIAL EEPROM INTERFACE

SLLS288B – FEBRUARY 1998 – REVISED MARCH 1998

6

POST OFFICE BOX 655303

differential driver switching characteristics over recommended ranges of operating free-air

full speed mode

PARAMETER

TEST CONDITIONS

MIN

MAX

UNIT

tr

Transition rise time for DP or DM

See Figure 1 and Figure 2

4

20

ns

tf

Transition fall time for DP or DM

See Figure 1 and Figure 2

4

20

ns

t(RFM)

Rise/fall time matching

(tr/tf) x 100

90

110

%

VO(CRS) Signal crossover output voltage

1.3

2.0

V

low speed mode

PARAMETER

TEST CONDITIONS

MIN

MAX

UNIT

tr

Transition rise time for DP to DM

CL = 50 pF to 350 pF,

See Figure 1 and Figure 2

75

300

ns

tf

Transition fall time for DP to DM

CL = 50 pF to 350 pF,

See Figure 1 and Figure 2

75

300

ns

t(RFM)

Rise/fall time matching

(tr/tf) x 100

80

120

%

VO(CRS) Signal crossover output voltage

CL = 50 pF to 350 pF

1.3

2.0

V

CL

15 k

Ω

15 k

Ω

CL

Full

Low

V(TERM) = 2.8 V

1.5 k

Ω

DP

DM

22

Ω

22

Ω

Characterization

measurement point

Figure 1. Differential Driver Switching Load

tr

90%

10%

VOH

VOL

DM

DP

90%

10%

tf

Figure 2. Differential Driver Timing Waveforms