max5591 Maxim Integrated Products, Inc., max5591 Datasheet - Page 16

• Manufacturer Part Number: max5591
• Description: Buffered, Fast-settling, Octal, 12/10/8-bit, Voltage-output Dacs
• Manufacturer: Maxim Integrated Products, Inc.

Buffered, Fast-Settling, Octal, 12/10/8-Bit,
Voltage-Output DACs
The MAX5590–MAX5595 octal, 12/10/8-bit, voltage-out-
put DACs offer buffered outputs and a 3µs maximum
settling time at the 12-bit level. The DACs operate from a
single 2.7V to 5.25V analog supply and a separate 1.8V
to AV
an input register and DAC register for each channel and
a 16-bit data-in/data-out shift register. The 3-wire serial
interface is compatible with SPI, QSPI, MICROWIRE, and
DSP applications. The MAX5590– MAX5595 provide two
user-programmable digital I/O ports, which are pro-
grammed through the serial interface. The externally
selectable power-up states of the DAC outputs are either
zero scale, midscale, or full scale.
The reference input, REF, accepts both AC and DC val-
ues with a voltage range extending from analog ground
(AGND) to AV
output of the DACs. Determine the output voltage using
the following equations:
Unity-gain versions:
Force-sense versions (FB_ connected to OUT_):
where CODE is the numeric value of the DAC’s binary
input code and N is the bits of resolution. For the
MAX5590/MAX5591, N = 12 and CODE ranges from 0
to 4095. For the MAX5592/MAX5593, N = 10 and
CODE ranges from 0 to 1023. For the MAX5594/
MAX5595, N = 8 and CODE ranges from 0 to 255.
The DACA and DACH output-buffer amplifiers of the
MAX5590–MAX5595 are unity-gain stable with rail-to-
rail output voltage swings and a typical slew rate
of 3.6V/µs (FAST mode). The MAX5590/MAX5592/
MAX5594 provide unity-gain outputs, while the
MAX5591/MAX5593/MAX5595 provide force-sense out-
puts. For the MAX5591/MAX5593/MAX5595, access to
the output amplifier’s inverting input provides flexibility
in output gain setting and signal conditioning (see the
Applications Information section).
The MAX5590–MAX5595 offer FAST and SLOW settling-
time modes. In the SLOW mode, the settling time is 6µs
(max), and the supply current is 3.2mA (max). In the
FAST mode, the settling time is 3µs (max), and the sup-
ply current is 8mA (max). See the Digital Interface section
for settling-time mode programming details.
16
______________________________________________________________________________________
DD
digital supply. The MAX5590–MAX5595 include
V
OUT
V
DD
OUT_
. The voltage at REF sets the full-scale
= 0.5 x (V
= (V
Detailed Description
REF
REF
x CODE) / 2
x CODE) / 2
Reference Input
Output Buffers
N
N
Use the serial interface to set the shutdown output
impedance of the amplifiers to 1kΩ or 100kΩ for the
MAX5590/MAX5592/MAX5594 and 1kΩ or high imped-
ance for the MAX5591/MAX5593/MAX5595. The DAC
outputs can drive a 10kΩ (typ) load and are stable with
up to 500pF (typ) of capacitive load.
At power-up, all DAC outputs power up to full scale,
midscale, or zero scale, depending on the configuration
of the PU input. Connect PU to DV
scale upon power-up. Connect PU to digital ground
(DGND) at power-up to set OUT_ to zero scale. Leave
PU floating to set OUT_ to midscale.
The MAX5590–MAX5595 use a 3-wire serial interface
that is compatible with SPI, QSPI, MICROWIRE, and DSP
protocol applications (Figures 1 and 2). Connect DSP to
DV
edge of SCLK. Connect DSP to DGND before power-up
to clock data in on the falling edge of SCLK. After power-
up, the device enters DSP frame-sync mode on the first
rising edge of DSP. Refer to the MAX5590–MAX5595
Programmer’s Handbook for details.
The MAX5590–MAX5595 include a 16-bit input shift
register. The data is loaded into the input shift register
through the serial interface. The 16 bits can be sent in
two serial 8-bit packets or one 16-bit word (CS must
remain low until all 16 bits are transferred). The data is
loaded MSB first. For the MAX5590/MAX5591, the 16
bits consist of 4 control bits (C3–C0) and 12 data bits
(D11–D0) (see Table 1). For the 10-bit MAX5592/
MAX5593 devices, D11–D2 are the data bits and D1
and D0 are sub-bits. For the 8-bit MAX5594/
MAX5595 devices, D11–D4 are the data bits and
D3–D0 are sub-bits. Set all sub-bits to zero for optimum
performance.
Each DAC channel includes two registers: an input reg-
ister and the DAC register. At power-up, the DAC out-
put is set according to the state of PU. The DACs are
double-buffered, which allows any of the following for
each channel:
• Loading the input register without updating the DAC
• Updating the DAC register from the input register
• Updating the input and DAC registers simultaneously
register
DD
before power-up to clock data in on the rising
Digital Interface
DD
Power-On Reset
to set OUT_ to full