AD8152-EVAL Analog Devices Inc, AD8152-EVAL Datasheet - Page 16

• Manufacturer Part Number: AD8152-EVAL
• Manufacturer: Analog Devices Inc

Specifications of AD8152-EVAL

• Lead Free Status / RoHS Status: Not Compliant

AD8152
Symbol
t
t
CONTROL INTERFACE
The AD8152 control interface receives and stores the desired
connection matrix and output levels for the 34 input and 34 output
signal pairs. The interface consists of 34 rows of double-rank
6-bit latches, one for each output. The 6-bit data-word stored
in these latches indicates to which (if any) of the 34 inputs the
output will be connected, as well as the full-scale output current.
One output at a time can be preprogrammed by addressing the
output and writing the desired connection data or output cur-
rent into the first rank of latches. This process can be repeated
until each of the desired output changes has been preprogrammed.
All output connections can then be programmed at once by passing
the data from the first rank of latches into the second rank. The
output connections always reflect the data programmed into the
second rank of latches and do not change until the first rank of
data is passed into the second rank.
If necessary for system verification, the data in the second rank
of latches can be read back from the control interface.
At any time, a reset pulse can be applied to the control interface to
globally reset the appropriate second rank data bits, disabling all 34
signal output pairs and resetting the output currents. To facilitate
multiple chip address decoding, there is a chip select pin. All logic
signals except the reset pulse are ignored unless the chip select
pin is active. The chip select pin disables only the control logic
interface and does not change the operation of the signal matrix.
The chip select pin does not power down any of the latches, so any
data programmed in the latches is preserved.
All control pins are level-sensitive, not edge-triggered.
CONTROL PIN DESCRIPTION
A[6:0] Inputs
Output address pins. The binary encoded address applied to the
lower A[5:0] input pins determines which of the 34 outputs is
being programmed (or being read back). The most significant bit,
A6, determines whether the data pins contain information for
the connection register bank or the output level register bank.
Using the broadcast address, A[5:0] = “111111” will simulta-
neously program data into all outputs at once.
D[5:0] Inputs/Outputs
Input configuration or output level data pins. In write mode,
when the bank selection bit A6 is LOW, the binary encoded data
applied to pins D[5:0] determine which of the 34 inputs is to be
TOD
TW
Disable Time
Width of Reset Pulse
OUT[0:33][N:P]
DISABLING
Parameter
Output Disable from Reset
OUTPUTS
RESET
Figure 5. Asynchronous Reset
Table IX. Asynchronous Reset
t
TOD
–16–
t
TW
connected to the output specified with the A[5:0] pins. The most
significant bit is D5, and the least significant bit is D0. To disable
an output completely, the input address D[5:0] = “111111”
should be written into the input configuration bank at the desired
output address.
In write mode, when the bank selection bit A6 is HIGH, the
binary encoded data applied to pins D[3:0] indicate the output
current level to be used for the output specified with the A[5:0]
pins. The reset default is “0111” for 16 mA. Each LSB is 2 mA.
In readback mode, pins D[5:0] are low impedance outputs
indicating the data-word stored in the second rank for the out-
put specified with the A[5:0] pins and the bank specified with
the A6 bit. The readback drivers were designed to drive high
impedances only, so external drivers connected to the D[5:0]
should be disabled during readback mode.
WE Input
First rank write enable. Forcing this pin to logic low allows the
data on pins D[5:0] to be stored in the first rank latch for the
output specified by pins A[6:0]. The WE pin must be returned to a
logic high state after a write cycle to avoid overwriting the first
rank data.
UPDATE Input
Second rank write enable. Forcing this pin to logic low allows the
data stored in all 34 first rank latches (in both banks) to be trans-
ferred to the second rank latches. The signal connection matrix
will be reprogrammed when the second rank data and levels are
changed. This is a global pin, transferring all 34 rows of data at
once. It is not necessary to program the address pins. It should
be noted that after initial power-up of the device, the first rank
data is undefined. It is desirable to preprogram all 17 outputs
before performing the first update cycle.
RE Input
Second rank read enable. Forcing this pin to logic low enables the
output drivers on the bidirectional D[5:0] pins, entering the read-
back mode of operation. By selecting an output address with the
A[6:0] pins and forcing RE to logic low, the 6-bit data stored in
the second rank latch for that output address will be written to
D[5:0] pins. Data should not be written to the D[5:0] pins
externally while in readback mode. The RE is a higher priority
pin than the WE pin, so first rank programming is not possible
while in readback mode.
Conditions
T
VCC = 3.3 V
A
= 25 C
Min
10
Typ
10
Max
25
Unit
ns
ns
REV. A