max5851 Maxim Integrated Products, Inc., max5851 Datasheet - Page 12

• Manufacturer Part Number: max5851
• Description: Max5851 Dual, 8-bit, 80msps, Current-output Dac
• Manufacturer: Maxim Integrated Products, Inc.

Dual, 8-Bit, 80Msps, Current-Output DAC
Table 1. Control Word Format and Function
Table 2. Configuration Modes
X = Don’t care.
Table 3. Gain Difference Setting
12
Normal operation;
noninterleaved inputs;
internal reference active
Normal operation;
noninterleaved inputs;
internal reference disabled
Normal operation;
interleaved inputs;
internal reference disabled
Standby
Power-down
Power-up
CONTROL WORD
GAIN ADJUSTMENT ON
______________________________________________________________________________________
MSB
PD
DACEN
CHANNEL A (dB)
REN
IDE
PD
G3
G2
G1
G0
MODE
-0.35
+0.4
0
DACEN
Power-Down. The part enters power-down mode if PD = 1.
DAC Enable. When DACEN = 0 and PD = 0, the part enters standby mode.
Interleaved Data Mode. IDE = 1 enables the interleaved data mode. In this mode, digital data for both
channels is applied through channel A in a multiplexed fashion. Channel B data is written on the falling edge
of the clock signal and channel A data is written on the rising edge of the clock signal.
Reference Enable Bit. REN = 0 activates the internal reference. REN = 1 disables the internal reference and
requires the user to apply an external reference between 0.1V to 1.32V.
Bit 3 (MSB) of Gain Adjust Word
Bit 2 of Gain Adjust Word
Bit 1 of Gain Adjust Word
Bit 0 (LSB) of Gain Adjust Word
PD
0
0
0
0
1
0
G3
0
1
1
IDE
DACEN
1
1
1
0
X
1
G2
0
0
1
IDE
G1
0
0
1
X
X
X
0
0
1
REN
REN
G0
X
X
X
0
1
1
0
0
1
At power-up, the MAX5851’s default configuration is inter-
nal reference, noninterleaved input mode with a gain of
0dB and a fully operational converter. In shutdown, the
MAX5851 consumes only 1µA of supply current, and in
standby the current consumption is 3.1mA. Wake-up time
from standby mode to normal operation is 3µs.
The MAX5851 allows both single-ended CMOS and dif-
ferential clock mode operation, and supports update
rates of up to 80Msps. These modes are selected
through an active-low control line called DCE. In single-
ended clock mode (DCE = 1), the CLK pin functions as
an input, which accepts a user-provided single-ended
clock signal. Data is written to the converter on the rising
edge of the clock. The DAC outputs (previous data) are
updated simultaneously on the same edge.
If the DCE pin is pulled low, the MAX5851 operates in
differential clock mode. In this mode, the clock signal
has to be applied to differential clock input pins
CLKXP/CLKXN. The differential input accepts an input
range of ≥0.5V
(CV
tude clock drives. CLKXP/CLKXN also help to minimize
the jitter, and allow the user to connect a crystal oscilla-
tor directly to the MAX5851.
The CLK pin now becomes an output, and provides a sin-
gle-ended replica of the differential clock signal, which
may be used to synchronize the input data. Data is writ-
ten to the device on the rising edge of the CLK signal.
FUNCTION
DD
G3
- 0.5V), making the part ideal for low-input ampli-
P-P
G2
and a common-mode range of 1V to
Device Power-Up and
States of Operation
G1
Clock Modes
LSB
G0