Datasheet

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AM3359, AM3358, AM3357
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www.ti.com SPRS717E –OCTOBER 2011–REVISED JANUARY 2013
5.5.2.1.2.9 LPDDR Signal Termination
There is no specific need for adding terminations on the LPDDR interface. However, system designers
may evaluate the need for serial terminators for EMI and overshoot reduction. Placement of serial
terminations for DQS[x] and DQ[x] net class signals should be determined based on PCB analysis.
Placement of serial terminations for ADDR_CTRL net class signals should be close to the AM335x device.
Table 5-38 shows the specifications for the serial terminators in such cases.
Table 5-38. LPDDR Signal Terminations
No. Parameter Min Typ Max Unit
1 CK net class
(1)
0 22 Zo
(2)
ohms
2 ADDR_CTRL net class
(1)(3)(4)
0 22 Zo
(2)
ohms
3 DQS0, DQS1, DQ0, and DQ1 net classes 0 22 Zo
(2)
ohms
(1) Only series termination is permitted.
(2) Zo is the LPDDR PCB trace characteristic impedance.
(3) Series termination values larger than typical only recommended to address EMI issues.
(4) Series termination values should be uniform across net class.
Copyright © 2011–2013, Texas Instruments Incorporated Peripheral Information and Timings 151
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