Rainbow Electronics MAX5858 - Manual (Page 13)

MAX5858
Dual, 10-Bit, 300Msps, Current-Output DAC with
4x/2x/1x Interpolation Filters
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Detailed Description
The MAX5858 dual, high-speed, 10-bit, current-output
DAC provides superior performance in communication
systems requiring low-distortion analog-signal recon-
struction. The MAX5858 combines two DACs with 2x/4x
programmable digital interpolation filters, divide-by-N
clock output, and an on-chip 1.24V reference. The cur-
rent outputs of the DACs can be configured for differen-
tial or single-ended operation. The full-scale output
current range is adjustable from 2mA to 20mA to opti-
mize power dissipation and gain control.
The MAX5858 accepts an input data rate to 165MHz or
a DAC conversion rate of 300MHz. The inputs are
latched on the rising edge of the clock whereas the out-
put latches on the following rising edge.
The two-stage digital interpolation filters are program-
mable to 4x, 2x, or no interpolation. When operating in
4x interpolation mode, the interpolator increases the
DAC conversion by a factor of four, providing a four-
fold increase in separation between the reconstructed
waveform spectrum and its first image.
The MAX5858 features three modes of operation: normal,
standby, and power-down. These modes allow efficient
power management. In power-down, the MAX5858 con-
sumes only 1µA of supply current. Wake-up time from
standby mode to normal DAC operation is 0.7µs.
Programming the DAC
An 8-bit control word routed through channel A’s data
port programs the gain matching, interpolator configu-
ration, and operational mode of the MAX5858. The con-
trol word is latched on the falling edge of CW. Table 1
represents the control word format and function.
The gain on channel A can be adjusted to achieve gain
matching between two channels in a user’s system.
The gain on channel A can be adjusted from -0.4dB to
0.35dB in steps of 0.05dB by using bits G3 to G0 (see
Table 3).
2x DIGITAL
INTERPOLATION
FILTER
2x DIGITAL
INTERPOLATION
FILTER
INPUT
REGISTER
10-BIT
300MHz
DAC
10 10 10 10
DA9–DA0
OUTPA
OUTNA
2x DIGITAL
INTERPOLATION
FILTER
2x DIGITAL
INTERPOLATION
FILTER
INPUT
REGISTER
10-BIT
300MHz
DAC
10 10 10 10
DB9–DB0
OUTPB
OUTNB
CONTROL REGISTER 1.24V REFERENCE AND CONTROL AMPLIFIER
CLK CLKXN CLKXP
F2EN
F1EN
AGND REFR
R SET
DGND CGND REFO REN
CW
IDE
DV DD CV DD AV DD
MAX5858
Simplified Block Diagram