AD5382BST-5 Analog Devices Inc, AD5382BST-5 Datasheet - Page 28

• Manufacturer Part Number: AD5382BST-5
• Description: IC DAC 14BIT 32CH 5V 100-LQFP
• Manufacturer: Analog Devices Inc

Specifications of AD5382BST-5

• Design Resources: 32 Channels of Programmable Voltage with Excellent Temperature Drift Performance Using AD5382 (CN0011) AD5382 Channel Monitor Function (CN0012)
• Settling Time: 8µs
• Number Of Bits: 14
• Data Interface: Serial, Parallel
• Number Of Converters: 32
• Voltage Supply Source: Single Supply
• Power Dissipation (max): 65mW
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 100-LQFP
• For Use With: EVAL-AD5382EB - BOARD EVAL FOR AD5382
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

AD5382
I
The AD5382 features an I
consisting of a serial data line (SDA) and a serial clock line
(SCL). SDA and SCL facilitate communication between the
AD5382 and the master at rates up to 400 kHz. Figure 6 shows
the 2-wire interface timing diagrams that incorporate three
different modes of operation. In selecting the I
mode, first configure serial operating mode (SER/ PAR = 1)
and then select I
Logic 1. The device is connected to the I
(no clock is generated by the AD5382). The AD5382 has a 7-bit
slave address, 1010 1AD1AD0. The 5 MSB are hard-coded and
the 2 LSB are determined by the state of the AD1 and AD0 pins.
The facility to hardware configure AD1 and AD0 allows four of
these devices to be configured on the bus.
I
One data bit is transferred during each SCL clock cycle. The
data on SDA must remain stable during the high period of the
SCL clock pulse. Changes in SDA while SCL is high are control
signals that configure start and stop conditions. Both SDA and
SCL are pulled high by the external pull-up resistors when the
I
Start and Stop Conditions
A master device initiates communication by issuing a start
condition. A start condition is a high-to-low transition on SDA
with SCL high. A stop condition is a low-to-high transition on
SDA while SCL is high. A start condition from the master
signals the beginning of a transmission to the AD5382. The stop
condition frees the bus. If a repeated start condition (Sr) is
generated instead of a stop condition, the bus remains active.
Repeated Start Conditions
A repeated start (Sr) condition can indicate a change of data
direction on the bus. Sr may be used when the bus master is
writing to several I
the bus.
Acknowledge Bit (ACK)
The acknowledge bit (ACK) is the ninth bit attached to any
8-bit data-word. ACK is always generated by the receiving
device. The AD5382 devices generate an ACK when receiving
an address or data by pulling SDA low during the ninth clock
period. Monitoring ACK allows detection of unsuccessful data
transfers. An unsuccessful data transfer occurs if a receiving
device is busy or if a system fault has occurred. In the event of
an unsuccessful data transfer, the bus master should reattempt
communication.
2
2
2
C Data Transfer
C bus is not busy.
C SERIAL INTERFACE
2
C mode by configuring the SPI /I
2
C devices and wants to maintain control of
2
C-compatible 2-wire interface
2
C bus as a slave device
2
C operating
2
C pin to a
Rev. B | Page 28 of 40
AD5382 Slave Addresses
A bus master initiates communication with a slave device by
issuing a start condition followed by the 7-bit slave address.
When idle, the AD5382 waits for a start condition followed by
its slave address. The LSB of the address word is the Read/ Write
(R/ W ) bit. The AD5382 is a receive-only device; when
communicating with the AD5382, R/ W = 0. After receiving the
proper address 1010 1AD1AD0, the AD5382 issues an ACK by
pulling SDA low for one clock cycle.
The AD5382 has four different user-programmable addresses
determined by the AD1 and AD0 bits.
Write Operation
Data can be written to the AD5382 DAC in three specific
modes.
4-Byte Mode
When writing to the AD5382 DACs, the user must begin with
an address byte (R/ W = 0) after which the DAC acknowledges
that it is prepared to receive data by pulling SDA low. The
address byte is followed by the pointer byte; this addresses the
specific channel in the DAC to be addressed and is also
acknowledged by the DAC. Two bytes of data are then written
to the DAC, as shown in Figure 31. A stop condition follows.
This allows the user to update a single channel within the
AD5382 at anytime and requires four bytes of data to be
transferred from the master.
3-Byte Mode
In 3-byte mode, the user can update more than one channel in
a write sequence without having to write the device address
byte each time. The device address byte is required only once;
subsequent channel updates require the pointer byte and the
data bytes. In 3-byte mode, the user begins with an address byte
(R/ W = 0), after which the DAC acknowledges that it is
prepared to receive data by pulling SDA low. The address byte
is followed by the pointer byte. This addresses the specific
channel in the DAC to be addressed and is also acknowledged
by the DAC. This is then followed by the two data bytes. REG1
and REG0 determine the register to be updated.
If a stop condition does not follow the data bytes, another
channel can be updated by sending a new pointer byte followed
by the data bytes. This mode requires only three bytes to be sent
to update any channel once the device is initially addressed, and
reduces the software overhead in updating the AD5382
channels. A stop condition at any time exits this mode.
Figure 32 shows a typical configuration.