AD8152JBP Analog Devices Inc, AD8152JBP Datasheet - Page 17

• Manufacturer Part Number: AD8152JBP
• Description: Digital Crosspoint 34 x 34 X-Point SW 3.2Gbps 256-Pin SBGA
• Manufacturer: Analog Devices Inc

Specifications of AD8152JBP

• Package: 256SBGA
• Array Configuration: 34x34
• Number Of Arrays: 1
• Maximum Data Rate: 3.2 Gbps
• Power Supply Type: Single
• Minimum Single Supply Voltage: 2.25 V
• Maximum Single Supply Voltage: 3.63 V
• Rohs Status: RoHS non-compliant
• Function: Crosspoint Switch
• Circuit: 1 x 34:34
• Voltage Supply Source: Single Supply
• Voltage - Supply, Single/dual (±): 2.5 V ~ 3.3 V
• Current - Supply: 32mA
• Operating Temperature: 0°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 256-BGA Exposed Pad, 256-eBGA, 256-HBGA

CS Input
Chip select. This pin must be forced to logic low to program or
receive data from the logic interface, with the exception of the
RESET pin, described below. This pin has no effect on the signal
pairs and does not alter any of the stored control data.
RESET Input
Global output disable pin. Forcing the RESET pin to logic low
will disable all outputs, setting both ranks of all 34 input connec-
tion latches, regardless of the state of any other pins. This has the
effect of immediately disabling the 34 output signal pairs in the
matrix. The output level information is also changed. It is necessary
to momentarily hold RESET at a logic low state when powering
up the AD8152 in order to avoid random internal contention
where multiple inputs may be connected to one output. The
RESET pin is not gated by the state of the chip select pin, CS.
Control Interface Levels
The AD8152 control interface shares the data path supply pins,
VCC and VEE. The potential between the positive logic supply
VCC and the negative supply VEE must be at least 2.25 V and no
more than 3.63 V. Regardless of supply, the logic threshold is
approximately one-half the supply range, allowing the interface
to be used with most LVCMOS and LVTTL logic drivers.
Output Addressing
The AD8152 is programmed using a memory interface module,
with parallel address and data buses. Six bits (A5:A0) are used to
address the outputs. By setting the decimal value of these address
bits to a value from 0 to 33 inclusive, then one of the 34 outputs
is uniquely addressed.
One additional code, 63 (all 1s), is used for the broadcast mode.
If this address is selected, then all outputs will receive the same
programming. The remaining addresses in the space are not
valid and are reserved, Codes 34 to 66 inclusive. (See Table I.)
Connection and Output Current Programming
A seventh address bit (A6) determines which of two types of
programming is selected. If A6 = 0, connection matrix program-
ming is selected. If A6 = 1, output current programming is selected.
Using the Data Bus
Once it is determined which output is to be programmed (or broad-
cast to all outputs) and which type of programming (connection/
output-current), then the data bits (D5:D0) further define the
programming action.
If the selection is connection programming (A6 = 0), then the data
bits select the input that is to be connected to the addressed
output. If the broadcast address is selected, then the data bits select
the input that will be connected to all 34 outputs. (See Table II.)
A disable code (D5:D0 = 63, or all 1s) is used to disable (and
power down) the particular output that is addressed. A broadcast
disable can be effected by setting Code 63 on both the address
bus and the data bus along with A6 = 0.
Output-Current Programming
A current source in each output can be digitally programmed to
any one of 16 different current levels. Changing these current
levels will change the amplitude of the output swing that is
developed across the internal 50 W termination resistors.
To program the current for a particular output, its address is set on
A5:A0 (00–33), while A6 is set to 1. The four LSBs of the data
address (D3:D0) are then used to select one of the 16 output
current levels. D4 and D5 are “don’t cares” for output current
programming. (See Table III.)
REV. A
–17–
If it is desired to program all outputs to the same current level,
then the broadcast Code 63 can be placed on the address bus
(A5:A0), along with A6 = 1. (D3:D0) will then program all output
currents to the same level.
When the current code is set to 0000, a minimum current level
of 2 mA is obtained. For any other code, the current can be
calculated by (current code) ¥ 2 mA + 2 mA. Refer to Table III.
For example, 16 mA can be programmed by Code 0111. This is
7 ¥ 2 mA + 2 mA = 16 mA.
Register-Control Signals
Several single-ended logic input pins control the register loading
associated with the address and data buses described in the previ-
ous section. The control functions are tabulated in Table IV.
There are dual ranks of registers for the data that programs the
AD8152. The first rank registers accumulate the data for the
various outputs as they are being programmed one by one. The
second rank registers actually control the functions of the device.
The RESET signal is used to reset the connection matrix, disable
all outputs, and set all of the output currents to a default condition
at Code 0111. This action sets the output current to a nominal
value of 16 mA. The data in the first rank latches is also reset by
the assertion of RESET.
The CS signal is used to enable the control interface. If several
devices are used in a system with the other control signals
bussed, the CS signal can be used to select an individual device
to change its programming.
The WE signal is used to enable writing data to the first rank
registers. This data will not immediately affect the features of
the AD8152.
The UPDATE signal transfers the data from the first rank registers
to the second rank registers. After assertion of UPDATE, the
data actively controls the AD8152 functions.
The second rank registers can be read back through the data bus.
The output is addressed on A5:A0 and the connection/current is
selected via A6. Asserting RE will cause the second rank data to
appear on the data bus. The RE function will dominate over
WE if both are asserted at the same time. Broadcast readback is
not permitted.
Some typical programming waveforms for the control signals are
provided in Figure 6.
Input/Output Coupling
The AD8152 has internal 50 W termination resistors for each
single-ended input and output. This can also provide a 100 W
termination for a 100 W differential transmission line. All of the
input termination resistors connect to one common point called
VTTI. Similarly, each of the output termination resistors connects
to one common point called VTTO. The voltage can be set
independently at VTTI and VTTO to accommodate various
interface architectures.
UPDATE
A[6:0
D[5:0
WE
]
]
Figure 6. Programming Waveforms
VALID ADDRESS INPUT
VALID DATA INPUT
VALID ADDRESS INPUT
VALID DATA INPUT
AD8152