AD8152-EVAL Analog Devices Inc, AD8152-EVAL Datasheet - Page 19

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

Specifications of AD8152-EVAL

• Lead Free Status / RoHS Status: Not Compliant

AD8152 POWER CONSUMPTION
There are several sections of the AD8152 that draw varying
power depending on the supply voltages, the type of I/O coupling
used, and the status of the AD8152 operation. Figure 9 shows a
block diagram of these sections. These are described briefly below
and then in detail later in the data sheet. Table X summarizes the
power consumption of each section and is a useful guide as the
following sections are reviewed.
The first section is the input termination resistors. The power
dissipated in the termination resistors is the result of their being
driven by the respective driving stage. Also, there might be dc power
dissipated in the input termination resistors if the inputs are
dc-coupled and the driving source reference is a dc voltage that is
not equal to VTTI.
In the next section, the active part of the input stages, each input
is powered only when it is selected. If an input is not selected, it
Quiescent Current
Current per Active Channel
Current per Active Channel
V
V
2.5 V Operation (VCC – VEE = 2.5 V, VTTO = 2.5 V, I
Per Channel Power
Power for All Channels Active
Percentage of Total Power
3.3 V Operation (VCC – VEE = 3.3 V, VTTO = 3.3 V, I
Per Channel Power
Power for All Channels Active
Percentage of Total Power
REV. A
IN
OUT
for Differential
= 800 mV p-p Sine
= 800 mV p-p
INN
INP
P =
INPUT
TERMINATIONS
50
(V
VTTI
indiffrms
100
50
Input
Termination
Resistors
V
566 mV rms/100
= 5.66 mA
3.2 mW
108.8 mW
5%
3.2 mW
108.8 mW
4%
)
2
IN
/(R
INPUTS
I = 2mA
ACTIVE
INPUT
PER
TERMINATION
Figure 9. Power Consumption Block Diagram
I = 32mA
SWITCH
MATRIX
Table X. Power Consumption
VCC
) 2 mA
Input
Stage
2 mA
5 mW
170 mW
8%
6.6 mW
224 mW
9%
OUT
OUT
VEE
I = .25 I
OUTPUT
PRE-
DRIVER
= 16 mA)
= 16 mA)
–19–
OUT
Core
32 mA
4 mA
80 mW
4%
106 mW
4%
OUT-
PUTS
is powered down. Thus, the total number of active inputs will
affect the total power consumption.
The core of the device performs the crosspoint switching function.
It draws a fixed quiescent current whenever the AD8152 is
powered from VCC to VEE.
An output predriver section draws a current that is proportional
to the programmed output current, I
flows from VCC to VEE. It is treated separately from the output
current, which flows from VTTO, and might not be the same
voltage as VCC.
The final section is the outputs. For an individual output, the
programmed output current will flow through two separate paths.
One is the on-chip termination resistor, and the other is the
transmission line and the destination termination resistor. The
nominal parallel impedance of these two paths is 25 W. The sum
50
VTTO
I
OUT
OUTPUT TERMINATIONS
50
Output
Predriver
0.25 ¥ I
4 mA
10 mW
340 mW
17%
13.2 mW
449 mW
17%
P =
OUTN
OUTP
P =
V
OL
I
(V
OUT
= V
2
OL
OUT
TTO
50
) (I
OUT
– (I
OPTIONAL COUPLING CAPACITORS
)
OUT
Output
Termination
Resistors
0.5 ¥ I
8 mA
8 mW
272 mW
13.6%
8 mW
272 mW
10%
50
25 )
VTT
OUT
50
DRIVEN DEVICE
TERMINATIONS
OUT
. This current always
Output
Switch +
Current
Source
I
16 mA
33.6 mW
1.03 W
51%
46.4 mW
1.47 W
56%
OUT
AD8152
Total
Power
2.0 W
2.63 W