Datasheet


      
   
SLAS259B − DECEMBER 1999 − REVISED APRIL 2004
12
WWW.TI.COM
APPLICATION INFORMATION
serial interface (continued)
If there is no need to have more than one device on the serial bus, then CS can be tied low. Figure 16 shows
an example of how to connect the TLV5606 to a TMS320, SPI, or Microwire port using only three pins.
TMS320
DSP
FSX
DX
CLKX
TLV5606
FS
DIN
SCLK
CS
SPI
SS
MOSI
SCLK
TLV5606
FS
DIN
SCLK
CS
Microwire
I/O
SO
SK
TLV5606
FS
DIN
SCLK
CS
Figure 16. Three-Wire Interface
Notes on SPI and Microwire: Before the controller starts the data transfer, the software has to generate a falling
edge on the I/O pin connected to FS. If the word width is 8 bits (SPI and Microwire), two write operations must
be performed to program the TLV5606. After the write operation(s), the DAC output is updated automatically
on the next positive clock edge following the sixteenth falling clock edge.
serial clock frequency and update rate
The maximum serial clock frequency is given by:
f
SCLKmax
+
1
t
wH(min)
) t
wL(min)
+ 20 MHz
The maximum update rate is:
f
UPDATEmax
+
1
16
ǒ
t
wH(min)
) t
wL(min)
Ǔ
+ 1.25 MHz
The maximum update rate is a theoretical value for the serial interface, since the settling time of the TLV5606
has to be considered also.
data format
The 16-bit data word for the TLV5606 consists of two parts:
D Control bits (D15 . . . D12)
D New DAC value (D11 ...D2)
D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0
X SPD PWR X New DAC value (10 bits) 0 0
X: don’t care
SPD: Speed control bit. 1 → fast mode 0 → slow mode
PWR: Power control bit. 1 → power down 0 → normal operation
In power-down mode, all amplifiers within the TLV5606 are disabled.