Rainbow Electronics MAX5123 - Manual (Page 12)

MAX5122/MAX5123
+5V/+3V, 12-Bit, Serial, Force/Sense DACs
with 10ppm/°C Internal Reference
12 ______________________________________________________________________________________
Power-Down Lockout Input (
PDL
)
The power-down lockout pin (PDL) disables shutdown
when low. When in shutdown mode, a high-to-low tran-
sition on PDL will wake up the DAC with its output still
set to the state prior to power-down. PDL can also be
used to wake up the device asynchronously.
Power-Down Input (PD)
Pulling PD high places the MAX5122/MAX5123 in shut-
down. Pulling PD low will not return the MAX5122/
MAX5123 to normal operation. A high-to-low transition
on PDL or appropriate commands (Table 1) via the ser-
ial interface are required to exit power-down mode.
Serial-Interface Configuration
(SPI/QSPI/MICROWIRE/PIC16/PIC17)
The MAX5122/MAX5123 3-wire serial interface is com-
patible with SPI, QSPI, PIC16/PIC17 (Figure 4) and
MICROWIRE (Figure 5) interface standards. The 2-
byte-long serial input word contains three control bits,
12 data bits in MSB-first format, and one sub-bit, which
is always zero (Table 2).
The MAX5122/MAX5123’s digital inputs are double
buffered, which allows the user to:
•
Load the input register without updating the DAC
register,
•
Update the DAC register with data from the input
register,
•
Update the input and DAC registers concurrently.
Load input register; DAC register unchanged. 12-Bit DAC Data 0 0
0
1
0
Update DAC register from input register; exit shutdown. XXXXXXXXXXXX 0 1
1
1
0 Simultaneously load input and DAC registers; exit shutdown. 12-Bit DAC Data 0
UPO goes low (default). XXXXXXXXXXXX 1 0
0
0
1
Mode 1; DOUT clocked out on SCLK’s rising edge. 1XXXXXXXXXXX 1 1
1
1
0 UPO goes high. XXXXXXXXXXXX 1
No operation. XXXXXXXXXXXX 0
Shutdown DAC (provided PDL = 1). XXXXXXXXXXXX 1
Mode 0; DOUT clocked out on SCLK’s falling edge (default). 00XXXXXXXXXX 1 1 1
C1 C0 C2
FUNCTION
D11 ............... D0
Table 1. Serial-Interface Programming Commands
X = Don’t care * S0 is a sub-bit and always zero.
DIN
SCLK
CS
MOSI
SCK
I/O
SPI/QSPI
PORT
(PIC16/PIC17)
SS
V
DD
CPOL = 0, CPHA = 0
(CKE = 1, CKP = 0, SMP= 0
SSPM3 - SSPM0 = 0001)
( ) ARE FOR PIC16/PIC17 ONLY.
MAX5122
MAX5123
Figure 4. SPI/QSPI Interface Connections (PIC16/PIC17)
DIN
SCLK
CS
SK
SO
I/O
MICROWIRE
PORT MAX5122
MAX5123
Figure 5. MICROWIRE Interface Connections
16-BIT SERIAL WORD
0
S0*
0
0
0
0
0
0
0
0
S0*