MAX5811 Maxim, MAX5811 Datasheet - Page 7

• Manufacturer Part Number: MAX5811
• Description: 10-Bit / Low-Power / 2-Wire Interface / Serial / Voltage-Output DAC
• Manufacturer: Maxim

The MAX5811 is a 10-bit, voltage-output DAC with an
I
consists of a serial interface, power-down circuitry,
input and DAC registers, a 10-bit resistor string DAC,
unity-gain output buffer, and output resistor network.
The serial interface decodes the address and control
bits, routing the data to either the input or DAC register.
Data can be directly written to the DAC register imme-
diately updating the device output, or can be written to
the input register without changing the DAC output.
Both registers retain data as long as the device is pow-
ered.
The MAX5811 uses a segmented resistor string DAC
architecture, which saves power in the overall system
and guarantees output monotonicity. The MAX5811’s
input coding is straight binary, with the output voltage
given by the following equation:
where N = 10 (bits), and D = the decimal value of the
input code (0 to 1023).
The MAX5811 analog output is buffered by a precision,
unity-gain follower that slews at about 0.5V/µs. The
Table 1. Power-Down Command Bits
2
C/SMBus-compatible 2-wire interface. The device
PD1
PIN
COMMAND BITS
POWER-DOWN
0
0
1
1
1
2
3
4
5
6
10-Bit Low Power 2-Wire Interface Serial,
NAME
GND
PD0
SDA
ADD
OUT
V
SCL
_______________________________________________________________________________________
0
1
0
1
DD
V
OUT
Detailed Description
=
Power Supply and DAC Reference Input
Ground
Bidirectional Serial Data I/O
Serial Clock Line
Address Select. A logic high sets the address LSB to 1, a logic low sets the address LSB to 0.
Analog Output
V
Power-up device. DAC output restored to previous value.
Power-down mode 0. Power-down device with output floating.
Power-down mode 1. Power-down device with output terminated with 1kΩ to GND.
Power-down mode 2. Power-down device with output terminated with 100kΩ to GND.
REF
2
N
×
( )
D
DAC Operation
Output Buffer
buffer output swings rail-to-rail, and is capable of dri-
ving 5kΩ in parallel with 200pF. The output settles to
±0.5LSB within 4µs.
The MAX5811 features an internal POR circuit that ini-
tializes the device upon power-up. The DAC registers
are set to zero scale and the device is powered-down
with the output buffer disabled and the output pulled to
GND through the 100kΩ termination resistor. Following
power-up, a wake-up command must be initiated
before any conversions are performed.
The MAX5811 has three software-controlled low-power
power-down modes. All three modes disable the output
buffer and disconnect the DAC resistor string from V
reducing supply current draw to 300nA. In power-down
mode 0, the device output is high impedance. In
power-down mode 1, the device output is internally
pulled to GND by a 1kΩ termination resistor. In power-
down mode 2, the device output is internally pulled to
GND by a 100kΩ termination resistor. Table 1 shows
the power-down mode command words.
Upon wake-up, the DAC output is restored to its previ-
ous value. Data is retained in the input and DAC regis-
ters during power-down mode.
The MAX5811 features an I
wire interface consisting of a serial data line (SDA) and
MODE/FUNCTION
FUNCTION
Voltage-Output DAC
2
Power-Down Modes
C/SMBus-compatible 2-
Pin Description
Digital Interface
Power-On Reset
DD
7
,