MAX5180 Maxim, MAX5180 Datasheet - Page 8

• Manufacturer Part Number: MAX5180
• Description: Dual / 10-Bit / 40MHz / Current/Voltage Simultaneous-Output DACs
• Manufacturer: Maxim

Dual, 10-Bit, 40MHz, Current/Voltage
Simultaneous-Output DACs
Figure 1. Functional Diagram
The MAX5180/MAX5183 are dual 10-bit digital-to-ana-
log converters (DACs) capable of operating with clock
speeds up to 40MHz. Each of these dual converters
consists of separate input and DAC registers, followed
by a current source array capable of generating up to
1.5mA full-scale output current (Figure 1). An integrat-
ed +1.2V voltage reference and control amplifier deter-
mine the data converters’ full-scale output currents/
voltages. Careful reference design ensures close gain
matching and excellent drift characteristics. The
MAX5183’s voltage output operation features matched
400Ω on-chip resistors that convert the current array
current into a voltage.
The MAX5180/MAX5183 provide an integrated
50ppm/°C, +1.2V, low-noise bandgap reference that
can be disabled and overridden by an external refer-
ence voltage. REFO serves either as an external refer-
ence input or an integrated reference output. If REN is
connected to AGND, the internal reference is selected
and REFO provides a +1.2V output. Due to its limited
8
*INTERNAL 400Ω AND 9.6kΩ
Internal Reference and Control Amplifier
RESISTORS FOR MAX5183 ONLY.
_______________________________________________________________________________________
CLK
REFO
REFR
Detailed Description
*
9.6k
1.2V REF
REN
MSB DECODE
LATCHES
LATCHES
OUTPUT
INPUT
AV
DAC 1 SWITCHES
DAC 2 SWITCHES
DD
D9–D0
SOURCE ARRAY
CURRENT-
AGND
MSB DECODE
LATCHES
LATCHES
OUTPUT
INPUT
10µA output drive capability, REFO must be buffered
with an external amplifier if heavier loading is required.
The MAX5180/MAX5183 also employ a control amplifier
designed to simultaneously regulate the full-scale out-
put current (I
output current is calculated as follows:
where I
V
R
amplifier’s output current on the MAX5180 (Figure 2).
This current is mirrored into the current-source array
where it is equally distributed between matched current
segments and summed to valid output current readings
for the DACs.
The MAX5183 converts each output current (DAC1 and
DAC2) into an output voltage (V
internal, ground-referenced 400Ω load resistors. Using
the internal +1.2V reference voltage, the MAX5183’s
integrated reference output current resistor (R
9.6kΩ) sets I
REFO/
SET
CS
is the reference resistor that determines the
R
REF
SET
DACEN
) and I
REF
is the reference output current (I
FS
DV
MAX5180
MAX5183
DD
) for both outputs of the devices. The
to 125µA and I
FS
PD
DGND
I
FS
is the full-scale output current.
= 8 · I
OUT1N
CREF1
CREF2
OUT1P
OUT2P
OUT2N
REF
FS
OUT1
to 1mA.
, V
OUT2
) with two
REF
SET
=
=