System Overview
30
JAJU324B – March 2015 – Revised July 2017
翻訳版
—
最新の英語版資料
http://www-s.ti.com/sc/techlit/TIDU832
Copyright © 2015–2017, Texas Instruments Incorporated
EMI/EMC
規格準拠、産業用温度範囲のデュアルポート・ギガビット・イーサネットの
リファレンス・デザイン
2.3.1.3.3
Power Stage for AM3359 Host Processor
The power stage for the AM3359 Sitara is realized using the PMIC TPS65910A3 and a DDR3 terminator
regulator TPS51200. An additional TPS71718 LDO is used for the RTC circuit of the Sitara, as the
TPS65910A3 RTC circuit has been turned off.
The TPS65910A3 can be configured through I
2
C, this interface can be used to set internal registers of the
PMIC. For more details on these registers, see the TPS65910A3 user's guide. The TPS65910A3 have the
following power sources that can be used, each of the power supplies can be programmed to work at
several voltages. For the TPS65910A3, there are several boot modes depending on the device that needs
to be powered. Because the AM3359 is used, the EEPROM sequence has been chosen boot[1:0] = "10".
For more information on this topic, see
.
表
表
16. TPS65910A3 Default Voltage Rails per "10" EEPROM Sequence
RAIL NAME
TYPE
VOLTAGE OPTIONS
DEFAULT VOLTAGE
POWER
VIO
SMPS
1.5, 1.8, 2.5, or 3.3 V
1.5 V
1000 mA
VDD1
SMPS
0.6 to 1.5 V in 12.5-mV steps
Programmable multiplication factor: ×2, ×3
1.1 V
1.1 V
1500 mA
VDD2
SMPS
0.6 to 1.5 V in 12.5-mV steps
Programmable multiplication factor: ×2, ×3
1.1 V
1.1 V
1500 mA
VDD3
LDO
5 V or OFF
N/A
100 mA
VDIG1
LDO
1.2, 1.5, 1.8, or 2.7 V
1.8 V
300 mA
VDIG2
LDO
1, 1.1, 1.2, or 1.8 V
1.8 V
300 mA
VPLL
LDO
1.0, 1.1, 1.8, or 2.5 V
1.8 V
50 mA
VDAC
LDO
1.8, 2.6, 2.8, or 2.85 V
1.8 V
150 mA
VAUX1
LDO
1.8, 2.5, 2.8, or 2.85 V
1.8 V
300 mA
VAUX2
LDO
1.8, 2.8, 2.9, or 3.3 V
3.3 V
150 mA
VAUX33
LDO
1.8, 2.0, 2.8, or 3.3 V
3.3 V
150 mA
VMMC
LDO
1.8, 2.8, 3.0, or 3.3 V
3.3 V
300 mA
VRTC
LDO
1.8 V or OFF
OFF
OFF
The TPS51200 is used for the DDR3 ram as the sink/source termination regulator. The DDR memory
termination structure determines the main characteristics of the V
TT
rail, which is to be able to sink and
source current while maintaining acceptable V
TT
tolerances. The V
TT
accuracy has a direct impact on the
memory signal integrity, it is imperative to understand the tolerance requirements on V
TT
. The termination
current demand of the DDR3 is less than 1 A of burst current. The TPS51200 ensures the regulator output
voltage to be between V
TTREF
– 25 mV < V
TT
< V
TTREF
+ 25 mV.