max5774 Maxim Integrated Products, Inc., max5774 Datasheet - Page 20

• Manufacturer Part Number: max5774
• Description: 32-channel, 14-bit, Voltage-output Dacs With Serial Interface
• Manufacturer: Maxim Integrated Products, Inc.

32-Channel, 14-Bit, Voltage-Output
DACs with Serial Interface
real-time gain and offset errors associated with each
channel. The gain and offset registers can be
accessed individually or in pairs.
The gain word range is limited between 0 and 1. The
gain word is an unsigned 14-bit data word. A gain word
of 0000h is a special mapping to provide a gain of
absolute one, i.e., no gain correction. For all the other
gain word codes, the amount of gain correction varies
proportionally to the gain word’s decimal value. For
example, a gain word of 0001h is equivalent to a gain
of 0.5
(see
bits C3–C0 = 1000 (see Tables 7 and 8).
The offset has a range from -FS/2 to + (FS/2 - 1 LSB).
The offset word is a 14-bit data word represented in
two’s complement. For example, an offset word equiva-
lent to 1FFFh would provide an offset of FS/2 - 1 LSB
and offset word of 2000h would provide an offset of
-FS/2 (see
control bits C3–C0 = 1001 (see Tables 7 and 8).
Figure 5. Daisy-Chain Configuration
20
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Table
14
and a gain of 3FFFh is equivalent to 1 - 0.5
CONTROLLER
Table
9). To access the gain register, set control
DEVICE
10). To access the offset register, set
1
DIN(0)
SCLK
CS
DSP
DIN(1)
SCLK
CS
DSP
DIN(2)
SCLK
CS
DSP
MAX577_
MAX577_
MAX577_
DOUT(0)
DOUT(1)
DOUT(2)
14
The configuration register controls the advanced fea-
tures of the MAX5773/MAX5774/MAX5775. Write to the
configuration register by setting control bits C3–C0 =
1100 and address bits 000000.
configuration register data format for the D13–D0 data
bits.
configuration register.
The MAX5773/MAX5774/MAX5775 provide a hardware-
selectable DSP-interface mode. The active-low DSP
logic input selects the microcontroller (µC)-interface or
DSP-interface mode. Drive DSP high for µC-interface
mode. Drive D S P low for DSP-interface mode. DSP
mode, when active, allows chip select (C S) to go high
before the entire 32-bit command word is clocked in.
Figure
interface modes.
When SING = 0, the MAX5773/MAX5774/MAX5775 are
in daisy-chain mode. For daisy-chain operation, set
DSP high (µC mode) and SING = 0.
Table 9. Gain Register Code Values
Table 10. Offset Register Code Values
*1 LSB = FS/2
CODE (DATA BITS D13–D0)
CODE (DATA BITS D13–D0)
Table
1 illustrates serial timing for both µC- and DSP-
0000h
0001h
0002h
1FFFh
2000h
3FFEh
3FFFh
1FFFh
0001h
0000h
3FFFh
2000h
12 shows the commands controlled by the
14
:
:
:
:
Configuration Register
OFFSET VALUE*
Table
DSP Mode ( DSP )
GAIN VALUE
FS/2 - 1 LSB
Unity Gain
0.000061
0.499938
0.999877
0.999938
0.00012
+1 LSB
-1 LSB
-FS/2
0.5
11 shows the
0
:
:
:
:
SING