TECHNICAL INFORMATION
DIGITAL INPUTS
For each channel, the 16-bit digital angle is double buffered with
transparent latches (See FIGURE 1). The latch controls have
internal pull-up current sources to +5 V, this puts the latches in
the transparent mode when they are not connected.
Angle is determined by adding the logic bits. The enable inputs
are LL (1st Latch LSBs), LM (1st Latch MSBs), and LA (2nd
Latch All); see FIGURE 2 for timing.
OUTPUT SCALING AND REFERENCE LEVEL
ADJUSTMENT
The DRC-11522 operates like a multiplying D/A converter in that
the voltage of each output line is directly proportional to the ref-
erence voltage. The maximum line-to-line levels are determined
by the output amplifiers and are programmable for a gain of 0.5,
1.0, or 2.0 (See TABLE 2.).
OUTPUT PHASING AND OUTPUT SCALE FACTOR
The analog output signals have the following phasing:
sin = (REF * K) Ao [1 + A(θ)] sin θ
cos = (REF * K) Ao [1 + A(θ)] cos θ
The output amplifiers simultaneously track reference voltage
fluctuations because they are proportional to (REF * K). The
transformation ratio Aois determined by the programmable gain
inputs (0.5, 1.0, or 2.0). The maximum variation in Aofrom all
causes is 0.1%. The term A(θ) represents the variation of the
amplitude with the digital signal input angle. A(θ), which is called
the scale factor variation, is a smooth function of (θ) without dis-
continuities and is less than ±0.1% for all values of (θ) The total
maximum variation in Ao[1 + A(θ)] is therefore ±0.2%.
Because the amplitude factor (REF * K) Ao [1 + A(θ)] varies
simultaneously on all output lines, it is not a source of error when
the DRC-11522 is driving a ratiometric system. However, if the
outputs are used independently, as in x-y plotters, the amplitude
variations must be taken into account.
3
TABLE 2. PROGRAMMABLE GAIN
GC1-A
(PIN 7)
GC2-A
(PIN 8)
GAIN
(K)
GND
OPEN
OPEN
OPEN
GND
OPEN
0.5
1.0
2.0
GC1-B
(PIN 4)
GC2-B
(PIN 5)
GAIN
(K)
TABLE 3. PINOUTS
PIN FUNCTION PIN FUNCTION
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
LL-B
COS A
SIN A
GC1-B
GC2-B
Ref B
GC1-A
GC2-A
Ref A
COS B
SIN B
NC
+15 V
-15 V
LA-B
LA-A
LL-A
GND
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
Bit 16 (LSB)
Bit 15
Bit 14
Bit 13
Bit 12
Bit 11
Bit 10
Bit 9
Bit 8
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1 (MSB)
LM-A
LM-B
NOTE: Functions LL, LM, LA both A and B may be left unconnected
when not used.
TABLE 4. PIN DEFINITIONS
PIN DEFINITION
GND
B1-B16
LM-A
LM-B
LL-A
LL-B
LA-A
LA-B
+15 V
-15 V
Ref-A
Ref-B
GC1-A
GC2-A
GC1-B
GC2-B
Sin A
Cos A
Sin B
Cos B
Power Supply Ground
Digital Ground
Analog Signal Ground
Digital Input bits B1, = MSB = 180 degrees
High Byte Enable (B1-B8) for MSB’s 8-bit Input register of
channel A. Logic high enables, low holds.
High Byte Enable (B1-B8) for MSB’s 8-bit Input register
channel B Logic high enables, low holds.
Low Byte Enable (B9-B16) for LSB’s 8-bit Input register of
channel A. Logic high enables, low holds
Low Byte Enable (B9-B16) for LSB’s 8-bit Input register of
channel B. Logic high enables, low holds.
Channel A Load Converter. Logic high transfers Channel A
input registers data into 16-bit holding register. When
low, Channel A is in hold mode.
Channel B Load Converter. Logic high transfers Channel B
input registers data into 16-bit holding register. When
low, Channel B is in hold mode.
Power Supply Voltage.
Power Supply Voltage.
CAUTION:
REVERSAL OF POWER SUPPLIES
WILL DAMAGE THE CONVERTER.
Channel A reference voltage Input
Channel B reference voltage input
Channel A gain programming pin
Channel A gain programming pin
Channel B gain programming pin
Channel B gain programming pin
Analog output of Channel A
Analog output of Channel A
Analog output of Channel B
Analog output of Channel B