Data Sheet

ADBMS6821/ADBMS6822

SPECIFICATIONS

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Rev. B | 7 of 28

SPI/isoSPI Timing Specifications (Controller)

TJ = −40°C to +125°C, VDDS = 3 V, VDD = VP = 5 V, unless otherwise noted.

Table 9. SPI/isoSPI Timing Specifications (Controller)

Parameter

Description

Test Conditions/Comments

Min

Typ

Max

Unit

tCLK

SCK period1

4 Mbps unidirectional mode

0.25

µs

All other transceiver modes

0.5

µs

t1

PICO setup time before SCK latching edge

25

ns

t2

PICO hold time after SCK latching edge

25

ns

t3

SCK low

tCLK = t3 + t4

50

ns

t4

SCK high

tCLK = t3 + t4

50

ns

t5

CS rising edge to CS falling edge

1

µs

t6

SCK latching edge to CS rising edge1

0.5

µs

t7

CS falling edge to SCK latching edge1

2 Mbps with 1-bit latency mode

0.5

µs

4 Mbps unidirectional mode

0.5

µs

Used with ADBMS stack monitor peripheral

0.5

µs

All other cases

1

µs

t8

SCK nonlatching edge to POCI valid

55

ns

t9

SCK latching edge to short ±1 transmit pulse

50

ns

t10

CS transition to long ±1 transmit pulse

55

ns

1 These timing specifications are dependent on the delay through the cable and include allowances for 50 ns of delay in each direction. A value of 50 ns corresponds to

10 meters of Category 5 cable (which has a velocity of propagation of 66% the speed of light). Use of longer cables require derating these specifications by the amount of

additional delay.

SPI/isoSPI Timing Specifications (Peripheral)

TJ = −40°C to +125°C, VDDS = 3 V, VDD = VP = 5 V, unless otherwise noted.

Table 10. SPI/isoSPI Timing Specifications (Peripheral)

Parameter

Description

Test Conditions/Comments

Min

Typ

Max

Unit

t12

isoSPI data recognized to SCK latching edge

4 Mbps unidirectional transceiver mode

50

75

100

ns

All other transceiver modes

85

125

165

ns

t13

SCK pulse width

4 Mbps unidirectional transceiver mode

50

75

100

ns

All other transceiver modes

85

125

165

ns

t14

SCK nonlatching edge to isoSPI data transmit

Standard bidirectional isoSPI transceiver mode

85

125

165

ns

SCK latching edge to isoSPI data transmit

2 Mbps with 1-bit latency transceiver mode

55

ns

t15

CS falling edge to SCK nonlatching edge

PHA = 1

80

120

156

ns

t16

CS falling edge to isoSPI data transmit

Standard bidirectional isoSPI transceiver mode

150

220

295

ns

t17

CS rising edge to SCK latching edge

PHA = 1

80

120

156

ns

t18

CS rising edge to PICO rising edge

35

ns

tRTN

Data return delay

Standard bidirectional isoSPI transceiver mode

315

430

545

ns

2 Mbps with 1-bit latency transceiver mode

145

195

240

ns