AD8556ARZ Analog Devices Inc, AD8556ARZ Datasheet - Page 20

• Manufacturer Part Number: AD8556ARZ
• Description: IC AMP CHOPPER 2MHZ 10MA 8SOIC
• Manufacturer: Analog Devices Inc
• Series: DigiTrim®r
• Type: Instrumentation Amplifierr

Specifications of AD8556ARZ

• Operating Temperature: -40°C ~ 140°C
• Amplifier Type: Chopper (Zero-Drift)
• Number Of Circuits: 1
• Slew Rate: 1.2 V/µs
• Gain Bandwidth Product: 2MHz
• Current - Input Bias: 49nA
• Voltage - Input Offset: 2µV
• Current - Supply: 2mA
• Current - Output / Channel: 10mA
• Voltage - Supply, Single/dual (±): 4.5 V ~ 5.5 V
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC (3.9mm Width)
• No. Of Amplifiers: 1
• Bandwidth: 700kHz
• Rail To Rail I/o Type: Rail-Rail I/O
• No. Of Channels: 1
• Supply Voltage Range: 2.7V To 5.5V
• Amplifier Case Style: SOIC
• No. Of Pins: 8
• Number Of Channels: 1
• Number Of Elements: 5
• Power Supply Requirement: Single
• Common Mode Rejection Ratio: 80dB
• Unity Gain Bandwidth Product (typ): 8MHz
• Single Supply Voltage (typ): 5V
• Dual Supply Voltage (typ): Not RequiredV
• Power Supply Rejection Ratio: 109dB
• Rail/rail I/o Type: Rail to Rail Input/Output
• Single Supply Voltage (min): 4.5V
• Single Supply Voltage (max): 5.5V
• Dual Supply Voltage (min): Not RequiredV
• Dual Supply Voltage (max): Not RequiredV
• Operating Temp Range: -40C to 140C
• Operating Temperature Classification: Automotive
• Mounting: Surface Mount
• Pin Count: 8
• Package Type: SOIC N
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Output Type: -
• -3db Bandwidth: -
• Lead Free Status / Rohs Status: Compliant

AD8556
Initial State
Initially, all the polysilicon fuses are intact. Each parameter has
the value 0 assigned (see Table 11).
Table 11. Initial State Before Programming
Second Stage Gain Code = 0
First stage gain code = 0
Output offset code = 0
Master fuse = 0
When power is applied to a device, parameter values are taken
either from internal registers, if the master fuse is not blown, or
from the polysilicon fuses, if the master fuse is blown. Programmed
values have no effect until the master fuse is blown. The internal
registers feature power-on reset; therefore, the unprogrammed
devices enter a known state after power-up. Power-on reset
occurs when VDD is between 0.7 V and 2.2 V.
Simulation Mode
The simulation mode allows any parameter to be temporarily
changed. These changes are retained until the simulated value is
reprogrammed, the power is removed, or the master fuse is
blown. Parameters are simulated by setting Field 1 to 01, selecting
the desired parameter in Field 2, and the desired value for the
parameter in Field 4. Note that a value of 11 for Field 2 is ignored
during the simulation mode. Examples of temporary settings
are as follows:
• Setting the second stage gain code (Parameter 00) to 011 and
• Setting the first stage gain code (Parameter 01) to 000 1011
• Set the output offset code (Parameter 10) to 0100 0000 and
Programming Mode
Intact fuses give a bit value of 0. Bits with a desired value of 1
need to have the associated fuse blown. Because a relatively
large current is needed to blow a fuse, only one fuse can be
reliably blown at a time. Therefore, a given parameter value may
need several 38-bit words to allow reliable programming. A
5.25 V ( ± 0.25 V) supply is required when blowing fuses to
minimize the on resistance of the internal MOS switches that
blow the fuse. The power supply voltage must not exceed the
absolute maximum rating and must be able to deliver 250 mA
of current.
the second stage gain to 50 produces:
1000 0000 0001 01 00 10 0000 0011 0111 1111 1110.
and the first stage gain to 4.166 produces:
1000 0000 0001 01 01 10 0000 1011 0111 1111 1110.
A first stage gain of 4.166 with a second stage gain of 50 gives a
total gain of 208.3. This gain has a maximum tolerance of 2.5%.
the output offset to 1.260 V when VDD = 5 V and VSS = 0 V.
This output offset has a maximum tolerance of 0.8%:
1000 0000 0001 01 10 10 0100 0000 0111 1111 1110.
Second Stage Gain = 17.5
First stage gain = 4.0
Output offset = VSS
Master fuse not blown
Rev. A | Page 20 of 28
At least 10 μF (tantalum type) of decoupling capacitance is
needed across the power pins of the device during programming.
The capacitance can be on the programming apparatus as long
as it is within 2 inches of the device being programmed. An
additional 0.1 μ F (ceramic type) in parallel with the 10 μ F is
recommended within ½ inch of the device being programmed.
A minimum period of 1 ms should be allowed for each fuse to
blow. There is no need to measure the supply current during
programming.
The best way to verify correct programming is to use the read
mode to read back the programmed values. Then, remeasure
the gain and offset to verify these values. Programmed fuses
have no effect on the gain and output offset until the master
fuse is blown. After blowing the master fuse, the gain and
output offset are determined solely by the blown fuses, and
the simulation mode is permanently deactivated.
Parameters are programmed by setting Field 1 to 10, selecting
the desired parameter in Field 2, and selecting a single bit with
the value 1 in Field 4.
As an example, suppose the user wants to permanently set the
second stage gain to 50. Parameter 00 needs to have the value
0000 0011 assigned. Two bits have the value 1; therefore, two
fuses need to be blown. Because only one fuse can be blown at a
time, this code can be used to blow one fuse:
1000 0000 0001 10 00 10 0000 0010 0111 1111 1110.
The MOS switch that blows the fuse closes when the complete
packet is recognized and opens when the start-of-packet,
dummy, or end-of-packet fields are no longer valid. After 1 ms,
this second code is entered to blow the second fuse:
1000 0000 0001 10 00 10 0000 0001 0111 1111 1110.
To permanently set the first stage gain to a nominal value of
4.151, Parameter 01 needs to have the value 000 1011 assigned.
Three fuses need to be blown, and the following codes are used,
with a 1 ms delay after each code:
1000 0000 0001 10 01 10 0000 1000 0111 1111 1110
1000 0000 0001 10 01 10 0000 0010 0111 1111 1110
1000 0000 0001 10 01 10 0000 0001 0111 1111 1110.
To permanently set the output offset to a nominal value of
1.260 V when VDD = 5 V and VSS = 0 V, Parameter 10 needs to
have the value 0100 0000 assigned. If one fuse needs to be
blown, use the following code:
1000 0000 0001 10 10 10 0100 0000 0111 1111 1110.
Finally, to blow the master fuse to deactivate the simulation
mode and prevent further programming, use code:
1000 0000 0001 10 11 10 0000 0001 0111 1111 1110.
There are 20 programmable fuses. Because each fuse requires
1 ms to blow, and each serial word can be loaded in 2.3 ms,
the maximum time needed to program the fuses can be as
low as 66 ms.