AD8280WASTZ Analog Devices Inc, AD8280WASTZ Datasheet - Page 18

no-image

AD8280WASTZ

Manufacturer Part Number
AD8280WASTZ
Description
Lithium Ion Battery Safety Monitor
Manufacturer
Analog Devices Inc
Datasheet

Specifications of AD8280WASTZ

Function
Battery Monitor
Battery Type
Lithium-Ion (Li-Ion)
Voltage - Supply
6 V ~ 30 V
Operating Temperature
-40°C ~ 105°C
Mounting Type
Surface Mount
Package / Case
48-LQFP
Lead Free Status / RoHS Status
Lead free / RoHS Compliant

Available stocks

Company
Part Number
Manufacturer
Quantity
Price
Part Number:
AD8280WASTZ
Manufacturer:
MICROCHIP
Quantity:
4 000
Part Number:
AD8280WASTZ
Manufacturer:
Analog Devices Inc
Quantity:
10 000
AD8280
TOP AND BOTTOM PART DESIGNATION
When configured in a daisy chain, the AD8280 operates differ-
ently, depending on where it is in the chain: top part (highest
potential), middle part, or bottom part (lowest potential). The
TOP and BOT pins are used to designate the location of each
part in the daisy chain. Table 6 is the logic table for identifying
the location of the part in the daisy chain or, when not used in
a daisy chain, identifying it as a single (standalone) part.
The logic high and logic low for the TOP and BOT pins are
different from those of the other logic pins of the AD8280.
The TOP and BOT pins are referenced to VTOP (logic high)
and VBOTx (logic low), respectively.
Table 6. Designation of the AD8280 in Daisy-Chain and
Standalone Configurations
Desired Condition
Middle part (middle potential part)
Bottom part (lowest potential part)
Top part (highest potential part)
Single part (highest and lowest potential part)
1
Bottom Part in Daisy-Chain Configuration
The bottom part in a daisy-chain configuration is the master
part and accepts voltage inputs into the ENBI and TESTI pins.
The AIINOV, AIINUV, and AIINOT pins of the bottom part
are connected to the AIOUTOV, AIOUTUV, and AIOUTOT
pins, respectively, of the next higher potential part in the daisy
chain. The AIOUTOV, AIOUTUV, and AIOUTOT pins of the
bottom part can be left floating, or they can be tied to part
ground (VBOTx).
Middle Part in Daisy-Chain Configuration
When the AD8280 is designated as a middle part, the AIINOV,
AIINUV, AIINOT, ENBO, and TESTO pins are connected to
the AIOUTOV, AIOUTUV, AIOUTOT, ENBI, and TESTI pins,
respectively, of the AD8280 above it.
Top Part in Daisy-Chain Configuration
When the AD8280 is designated as a top part, the AIINOV,
AIINUV, AIINOT, ENBO, and TESTO pins can be left floating,
or they can be tied to VTOP.
Standalone Part
When the AD8280 is designated as a single part (used as a stand-
alone part), the AIOUTOV, AIOUTUV, and AIOUTOT pins
can be left floating, or they can be tied to part ground (VBOTx).
The AIINOV, AIINUV, AIINOT, ENBO, and TESTO pins can
be left floating or tied to VTOP. The AD8280 accepts voltage
inputs into the ENBI and TESTI pins.
Alarm Signals in Daisy-Chain Configuration
Regardless of the part designation, the alarm signals are
available as voltage outputs on any part in the chain on the
AVOUTOV, AVOUTUV, and AVOUTOT pins. These signals
For the TOP and BOT pins only, Logic 1 is VTOP and Logic 0 is VBOTx.
TOP
0
0
1
1
1
BOT
0
1
0
1
Rev. A | Page 18 of 24
1
indicate the status of the part where the voltage alarms are
monitored, as well as the status of the parts above it in the daisy
chain. Make sure to use isolators to bring those signals outside
the high voltage battery environment.
TYPICAL DAISY-CHAIN CONNECTIONS
Figure 50 shows the typical connections for configuring the part
in a daisy chain.
SHARED OR SEPARATE ALARMS
The AD8280 can be configured for three separate alarms or for
one shared alarm. Tying the ALRMSEL pin to a 5 V logic high
forces the part into separate alarm mode. In this mode, each
alarm trips only for its designated monitoring function. That is,
the OV alarm trips only if an overvoltage condition exists at any
of the cell inputs, the UV alarm trips only if an undervoltage
condition exists at any of the cell inputs, and the OT alarm trips
only if an overtemperature condition exists at either of the
temperature inputs.
In shared alarm mode, any of the three conditions—overvoltage,
undervoltage, or overtemperature—trips the alarm on all three
signal chains. In shared mode, it is necessary to monitor only
one alarm because all three contain the same signal.
DEGLITCHING OPTIONS
The deglitching circuitry is available so that the part is immune
to transients occurring at the cell inputs. If a transient voltage of
a high or low enough level to trip an alarm occurs at the input
to the part, the alarm state does not occur if the transient
voltage is present for less than the selected deglitch time.
The DGT0, DGT1, and DGT2 pins are used to establish the
deglitch time. Table 7 shows the options available and the
corresponding logic levels to use when setting the deglitch
time with the DGT0, DGT1, and DGT2 pins.
Table 7. Fault Detection Time Pin Programming
Deglitch Time
0.0 sec
0.1 sec
0.8 sec
1.6 sec
3.2 sec
6.4 sec
12.8 sec
Do not tie all three deglitching pins (DGT0, DGT1, and DGT2)
to logic high (111); this setting is used only during the testing of
the part at the factory.
Setting the deglitch time to 0.0 sec (000) allows the use of an
external deglitching circuit, if desired. Additionally, when the
deglitch time is set to 0.0 sec, the time required to ensure that
the part has completed its self-test is significantly reduced (see
the Self-Test section). The DGTx pins should be tied to a fixed
logic level and not toggled or changed during operation of the
AD8280.
DGT0
0
0
0
0
1
1
1
DGT1
0
0
1
1
0
0
1
DGT2
0
1
0
1
0
1
0

Related parts for AD8280WASTZ