TMS320F2809, TMS320F2808, TMS320F2806
TMS320F2802, TMS320F2801, UCD9501
TMS320C2802, TMS320C2801, and TMS320F2801x DSPs
www.ti.com
SPRS230H–OCTOBER 2003–REVISED JUNE 2006
C10
C9
C8
(A)
XCLKIN
C6
C3
C1
C4
C5
(B)
XCLKOUT
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 6-4. Clock Timing
6.7 Power 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 pins prior to or
simultaneously with the VDDIO 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.
6.7.1 Power Management and Supervisory Circuit Solutions
Table 6-12 lists the power management and supervisory circuit solutions for 280x DSPs. LDO selection
depends on the total power consumed in the end application. Go to www.power.ti.com for a complete list
of TI power ICs or select TI DSP Power Solutions for links to the DSP Power Selection Guide
(slub006a.pdf) and links to specific power reference designs.
Table 6-12. Power Management and Supervisory Circuit Solutions
SUPPLIER
Texas Instruments
Texas Instruments
Texas Instruments
Texas Instruments
Texas Instruments
Texas Instruments
Texas Instruments
Texas Instruments
Texas Instruments
TYPE
LDO
PART
DESCRIPTION
TPS767D301 Dual 1-A low-dropout regulator (LDO) with supply voltage supervisor (SVS)
LDO
TPS70202
TPS766xx
TPS3808
TPS3803
TPS799xx
TPS736xx
TPS62110
TPS6230x
Dual 500/250-mA LDO with SVS
LDO
250-mA LDO with PG
SVS
Open Drain SVS with programmable delay
Low-cost Open-drain SVS with 5 µS delay
200-mA LDO in WCSP package
SVS
LDO
LDO
400-mA LDO with 40 mV of VDO
DC/DC
DC/DC
High Vin 1.2-A dc/dc converter in 4x4 QFN package
500-mA converter in WCSP package
Electrical Specifications
99
TI [ TEXAS INSTRUMENTS ]
