max5851 Maxim Integrated Products, Inc., max5851 Datasheet - Page 11

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

Figure 2. Simplified Diagram
DA6/DACEN
33, 39
36, 40
DA4/REN
PIN
DA5/IDE
32
34
35
37
38
DA0/G0
DA1/G1
DA2/G2
DA3/G3
DA7/PD
—
CLKXN
CLKXP
DGND
CGND
DV
CV
DCE
DB0
DB1
DB2
DB3
DB4
DB5
DB6
DB7
CLK
CW
DD
DD
OUTNB
OUTNA
OUTPB
OUTPA
NAME
AGND
REFR
AV
EP
DISTRIBUTION
MANAGEMENT
MANAGEMENT
INTERLEAVER
INPUT DATA
DD
Dual, 8-Bit, 80Msps, Current-Output DAC
______________________________________________________________________________________
DIGITAL
CLOCK
CLOCK
POWER
POWER
Full-Scale Current Adjustment. To set the output full-scale current, connect an external resistor R
between REFR and AGND. The output full-scale current is equal to 32 x V
Anal og P ow er Inp ut. S ee the P ow er S up p l i es, Byp assi ng , D ecoup l i ng , and Layout secti on for m or e d etai l s.
Channel B Negative Analog Current Output
Channel B Positive Analog Current Output
Analog Ground
Channel A Negative Analog Current Output
Channel A Positive Analog Current Output
Exposed Paddle. Connect EP to the common point of all ground planes.
MAX5851
CONTROLLER
CHANNEL A
OPERATING
CONTROL
DACA
DACB
8-BIT
8-BIT
MODE
GAIN
1.24V REFERENCE
AND CONTROL
AMPLIFIER
IDE
REN
MANAGEMENT
ANALOG
POWER
G0
G1
G2
G3
DACEN
PD
OUTNA
OUTNB
OUTPA
OUTPB
REFO
REFR
AGND
AV
AGND
DD
R
SET
The MAX5851 dual, high-speed, 8-bit, current-output
DAC provides superior performance in communication
systems requiring low-distortion analog-signal recon-
struction. The MAX5851 combines two DACs and an on-
chip 1.24V reference (Figure 2). The current outputs of
the DACs can be configured for differential or single-
ended operation. The full-scale output current range is
adjustable from 2mA to 20mA to optimize power dissi-
pation and gain control.
The MAX5851 accepts an input data and a DAC con-
version rate of 80MHz. The inputs are latched on the
rising edge of the clock whereas the output latches on
the following rising edge.
The MAX5851 features three modes of operation: normal,
standby, and power-down (Table 2). These modes allow
efficient power management. In power-down, the
MAX5851 consumes only 1µA of supply current. Wake-
up time from standby mode to normal DAC operation
is 3µs.
An 8-bit control word routed through channel A’s data
port programs the gain matching, reference, and the
operational mode of the MAX5851. The control word is
latched on the rising edge of CW. CW is independent
of the DAC clock. The DAC clock can always remain
running when the control word is written to the DAC.
Table 1 and Table 2 represent 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).
FUNCTION
Pin Description (continued)
Detailed Description
Programming the DAC
REFO
/R
SET
.
SET
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