SAM3703

SAM3703.pdf - Rev. 01/12

21

Command sequencing

The SDR SDRAM device must support following parameters.

Parameter

Symbol

Value

(50 MHz)

Value

(100 MHz)

MODE REGISTER SET command cycle time

tMRD

min 40 ns

min 20 ns

ACTIVE to PRECHARGE command

tRAS

min 60 ns

max 70 us

min 50 ns

max 70 us

ACTIVE to ACTIVE/AUTO REFRESH command period

tRC

min 80 ns

min 70 ns

AUTO REFRESH to ACTIVE/AUTO REFRESH command period

tRFC

min 80 ns

min 70 ns

ACTIVE to READ or WRITE delay

tRCD

min 20 ns

min 20 ns

PRECHARGE command period

tRP

min 20 ns

min 20 ns

ACTIVE bank a to ACTIVE bank b command

tRRD

min 20 ns

min 20 ns

WRITE recovery time

tWR

min 20 ns

min 20 ns

Exit self refresh to non-READ command

tXSNR

min 80 ns

min 80 ns

Exit self refresh to READ command

tXSRD

min 4 us

min 2 us

Average periodic REFRESH interval

tREFI

7.8 us

7.8 us

SAM3703 to SDR SDRAM

The outputs of SAM3703 meet following constraints.

Parameter

Symbol

Value

(50 MHz)

Value

(100 MHz)

Address and control hold time

tIH

min 8.8 ns

min 3.8 ns

Address and control setup time

tIS

min 8.3 ns

min 3.3 ns

DQ and DM setup time

tDS

min 14.3 ns

min 6.8 ns

DQ and DM hold time

tDH

min 3.8 ns

min 1.4 ns

SDR to SAM3703

The data from SDR to SAM3703 must meet following timing requirements. These parameters are

applicable at input of SAM3703, and must include effects of SDR device and effects of board

layout.

Parameter

Symbol

Value

DQ setup time

min 2.0 ns

DQ hold time

min 1.8 ns