Texas Instruments TMS320F28015 Power Sequencing, Xclkina Xclkoutb, Supplier Type Part Description

TMS320F2809, TMS320F2808, TMS320F2806

TMS320F2802, TMS320F2801, TMS320C2802

TMS320C2801, TMS320F28016, TMS320F28015

SPRS230L –OCTOBER 2003 –REVISED DECEMBER 2009 www.ti.com

C10

C8

XCLKIN(A)

C9

C3	C6
C1
	C4

C5

XCLKOUT(B)

A.The relationship of XCLKIN to XCLKOUT depends on the divide factor chosen. The waveform relationship shown is intended to illustrate the timing parameters only and may differ based on actual configuration.

B.XCLKOUT configured to reflect SYSCLKOUT.

Figure 6-7. Clock Timing

6.8Power Sequencing

No requirements are placed on the power up/down sequence of the various power pins to ensure the correct reset state for all the modules. However, if the 3.3-V transistors in the level shifting output buffers of the I/O pins are powered prior to the 1.8-V transistors, it is possible for the output buffers to turn on,

causing a glitch to occur on the pin during power up. To avoid this behavior, power the VDD (core voltage) pins prior to or simultaneously with the VDDIO (input/output voltage) pins, ensuring that the VDD pins have reached 0.7 V before the VDDIO pins reach 0.7 V.

There are some requirements on the XRS pin:

1.During power up, the XRS pin must be held low for tw(RSL1) after the input clock is stable (see Table 6-13). This is to enable the entire device to start from a known condition.

2.During power down, the XRS pin must be pulled low at least 8 μs prior to VDD reaching 1.5 V. This is to enhance flash reliability.

Additionally it is recommended that no voltage larger than a diode drop (0.7 V) should be applied to any pin prior to powering up the device. Voltages applied to pins on an unpowered device can bias internal p-n junctions in unintended ways and produce unpredictable results.

6.8.1Power Management and Supervisory Circuit Solutions

Table 6-12lists the power management and supervisory circuit solutions for 280x DSPs. LDO selection depends on the total power consumed in the end application. Go to http://www.power.ti.com for a complete list of TI power ICs.

Table 6-12. Power Management and Supervisory Circuit Solutions

SUPPLIER	TYPE	PART	DESCRIPTION
Texas Instruments	LDO	TPS767D301	Dual 1-A low-dropout regulator (LDO) with supply voltage supervisor (SVS)
Texas Instruments	LDO	TPS70202	Dual 500/250-mA LDO with SVS
Texas Instruments	LDO	TPS766xx	250-mA LDO with PG
Texas Instruments	SVS	TPS3808	Open Drain SVS with programmable delay
Texas Instruments	SVS	TPS3803	Low-cost Open-drain SVS with 5 μS delay
Texas Instruments	LDO	TPS799xx	200-mA LDO in WCSP package
Texas Instruments	LDO	TPS736xx	400-mA LDO with 40 mV of VDO
Texas Instruments	DC/DC	TPS62110	High Vin 1.2-A dc/dc converter in 4x4 QFN package
Texas Instruments	DC/DC	TPS6230x	500-mA converter in WCSP package

106 Electrical Specifications Copyright © 2003–2009, Texas Instruments Incorporated

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TMS320C2801 TMS320F28016 TMS320F28015