AD8156
ADDRESS PINS, A[3:0] INPUTS
The AD8156 feature sets can be set port by port or globally.
A[3:2] specify what is being programmed or read back when
the part is being configured port by port. Connectivity, output
current, equalization, or global programming features are
chosen based on the values of A[3:2]. Similarly, A[1:0] address
the port that is being programmed or read back. In global
programming, A[1:0] serve a different function. Refer to Table 9
to Table 15 for programming examples.
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DATA PINS, D[3:0] INPUTS/OUTPUTS
In readback mode, the D[3:0] pins are low impedance outputs
indicating the stored values in the memory to be read. The
readback drivers are designed to drive high impedances only,
so external drivers connected to D[3:0] must be disabled during
readback mode.
CONTROL INTERFACE LEVELS
The AD8156 control interface shares the data path supply pins,
V
CC
and V
EE
. The potential between the positive logic supply
V
CC
and the negative supply V
EE
must be at least 3.0 V and no
more than 3.7 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.
Table 7. Dual 2 × 2 Mode Programming Table
Address A[3:0]
Input A3 to Input A0 enable Output 3 to Output 0, respectively.
1 = Enables the output (for all A[3:0] inputs)
0 = Disables the output (for all A[3:0] inputs)
Data D[3:0]
Input D3 to Input D0 control the connectivity of Output 3 to Output 0, respectively.
0 = Input 2, 1 = Input 3 (for D2 and D3)
0 = Input 0, 1 = Input 1 (for D0 and D1)
Table 8. 4 × 4 Mode Programming Table
Mode
Write/Read Connectivity
and Disable
Address A[3:0]
0 0 A1 A0
A1 and A0 determine which
output is being programmed.
Data D[3:0]
0 D2 D1 D0
D1 and D0 determine which input is connected to which output;
D2 determines the enabled/disabled state of that output, with D2 = 1
(enable). When writing or reading, D3 is always 0.
D3 D2 D1 D0
D0 to D3 binarily program the output current level/voltage swing with the
output current = 2 mA + (2 mA × decimal (D[3:0])).
0 D2 D1 D0
D1 and D0 determine which input is connected to all of the outputs.
D2 determines the enabled/disabled state of all outputs with D2 = 1 (enable).
When writing or reading, D3 is always 0.
D3 D2 D1 D0
D0 to D3 binarily program the output current level/voltage swing with the
output current = 2 mA + (2 mA × decimal (D[3:0])). The value is written to
all outputs.
D3 D2 D1 D0
Data inputs D0 to D3 set the input equalization level where:
Gain(f) = D[3:0]/15 × 40 log
10
(f/0.83 GHz).
D3 D2 D1 D0
D0 to D3 set the input equalization level, where:
Gain(f) = D[3:0]15 × 40 log
10
(f0.83 GHz).
0 1 A1 A0
A1 and A0 determine which
output is being programmed.
1 0 0 0
Write/Read Output
Current Level
Broadcast
Connectivity/Disable
1 0 0 1
Broadcast Output
Current Level
Broadcast EQ Setting
1 0 1 1
Program EQ Setting
1 1 A1 A0
A1 and A0 determine which
input is being programmed.