DAC128S085

Manufacturer Part NumberDAC128S085
ManufacturerTexas Instruments
DAC128S085 datasheet
 


Specifications of DAC128S085

Resolution(bits)12Dac: Channels8
InterfaceSerial SPIOutput TypeVoltage
Output Range Max.(v Or Ma)5.5Settling Time(µs)8
Reference: TypeExtPower Consumption(typ)(mw)1.95
Dnl(max)(+/-lsb)0.75Inl(max)(+/-lsb)8
Pin/package16SON, 16TSSOP, 16WQFN, 16WSON  
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When the DAC128S085 first powers up, the DAC is in WRM.
In WRM, the registers of each individual DAC channel can be
written to without causing the DAC outputs to be updated.
This is accomplished by setting DB15 to "0", specifying the
DAC register to be written to in DB[14:12], and entering the
new DAC register setting in DB[11:0] (see Table 2).The
DAC128S085 remains in WRM until the mode of operation is
changed to WTM. The mode of operation is changed from
WRM to WTM by setting DB[15:12] to "1001". Once in WTM,
TABLE 2. Commands Impacted by WRM and WTM
DB15
DB[14:12]
0
0 0 0
D11 D10 ... D1 D0
0
0 0 1
D11 D10 ... D1 D0
0
0 1 0
D11 D10 ... D1 D0
0
0 1 1
D11 D10 ... D1 D0
0
1 0 0
D11 D10 ... D1 D0
0
1 0 1
D11 D10 ... D1 D0
0
1 1 0
D11 D10 ... D1 D0
0
1 1 1
D11 D10 ... D1 D0
As mentioned previously, the special command operations
can be exercised at any time regardless of the mode of op-
eration. There are three special command operations. The
first command is exercised by setting data bits DB[15:12] to
"1010". This allows a user to update multiple DAC outputs
simultaneously to the values currently loaded in their respec-
tive control registers. This command is valuable if the user
wants each DAC output to be at a different output voltage but
still have all the DAC outputs change to their appropriate val-
ues simultaneously (see Table 3).
The second special command allows the user to alter the DAC
output of channel A with a single write frame. This command
is exercised by setting data bits DB[15:12] to "1011" and data
bits DB[11:0] to the desired control register value. It also has
the added benefit of causing the DAC outputs of the other
channels to update to their current control register values as
well. A user may choose to exercise this command to save a
write sequence. For example, the user may wish to update
several DAC outputs simultaneously, including channel A. In
order to accomplish this task in the minimum number of write
DB[15:12]
DB[11:0]
1 0 1 0
X X X X H G F E D C B A
1 0 1 1
D11 D10 ... D1 D0
1 1 0 0
D11 D10 ... D1 D0
writing data to a DAC channel's register causes the DAC's
output to be updated as well. Changing a DAC channel's reg-
ister in WTM is accomplished in the same manner as it is done
in WRM. However, in WTM the DAC's register and output are
updated at the completion of the command (see Table 2).
Similarly, the DAC128S085 remains in WTM until the mode
of operation is changed to WRM by setting DB[15:12] to
"1000".
DB[11:0]
WRM: D[11:0] written to ChA's data register only
WTM: ChA's output is updated by data in D[11:0]
WRM: D[11:0] written to ChB's data register only
WTM: ChB's output is updated by data in D[11:0]
WRM: D[11:0] written to ChC's data register only
WTM: ChC's output is updated by data in D[11:0]
WRM: D[11:0] written to ChD's data register only
WTM: ChD's output is updated by data in D[11:0]
WRM: D[11:0] written to ChE's data register only
WTM: ChE's output is updated by data in D[11:0]
WRM: D[11:0] written to ChF's data register only
WTM: ChF's output is updated by data in D[11:0]
WRM: D[11:0] written to ChG's data register only
WTM: ChG's output is updated by data in D[11:0]
WRM: D[11:0] written to ChH's data register only
WTM: ChH's output is updated by data in D[11:0]
frames, the user would alter the control register values of all
the DAC channels except channel A while operating in WRM.
The last write frame would be used to exercise the special
command "Channel A Write Mode". In addition to updating
channel A's control register and output to a new value, all of
the other channels would be updated as well. At the end of
this sequence of write frames, the DAC128S085 would still
be operating in WRM (see Table 3).
The third special command allows the user to set all the DAC
control registers and outputs to the same level. This com-
mand is commonly referred to as "broadcast" mode since the
same data bits are being broadcast to all of the channels si-
multaneously. This command is exercised by setting data bits
DB[15:12] to "1100" and data bits DB[11:0] to the value that
the user wishes to broadcast to all the DAC control registers.
Once the command is exercised, each DAC output is updated
by the new control register value. This command is frequently
used to set all the DAC outputs to some known voltage such
as 0V, V
/2, or Full Scale. A summary of the commands
REF
can be found in Table 3.
TABLE 3. Special Command Operations
Description of Mode
Update Select: The DAC outputs of the channels selected with
a "1" in DB[7:0] are updated simultaneously to the values in
their respective control registers.
Channel A Write: Channel A's control register and DAC output
are updated to the data in DB[11:0]. The outputs of the other
seven channels are also updated according to their respective
control register values.
Broadcast: The data in DB[11:0] is written to all channels'
control register and DAC output simultaneously.
15
Description of Mode
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