ADP2291ARMZ-R7 Analog Devices Inc, ADP2291ARMZ-R7 Datasheet - Page 13

• Manufacturer Part Number: ADP2291ARMZ-R7
• Description: IC CHARGER LI-ION 4.2V 8MSOP
• Manufacturer: Analog Devices Inc

Specifications of ADP2291ARMZ-R7

• Battery Type: Lithium-Ion (Li-Ion)
• Function: Charge Management
• Voltage - Supply: 4.5 V ~ 12 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
• Input Voltage: 12V
• Battery Charge Voltage: 4.2V
• Charge Current Max: 1.5A
• Battery Ic Case Style: MSOP
• No. Of Pins: 8
• No. Of Series Cells: 1
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: ADP2291-EVAL - BOARD EVAL FOR ADP2291LI
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant
• Other names: ADP2291ARMZ-R7; ADP2291ARMZ-R7TR

In cases where the voltage drop across the protection device
must be kept low, a P MOSFET is recommended. Connect the
MOSFET as shown in Figure 21.
EXTERNAL PASS TRANSISTOR
Choose the external PNP pass transistor based on the given
operating conditions and power handling capabilities. The pass
device is determined by the base drive available, the input and
output voltage, and the maximum charge current.
Select the pass transistor with a collector-emitter breakdown
voltage that exceeds the maximum adapter voltage. A V
rating of at least 15 V is recommended.
Providing a charge current of I
of 40 mA requires a PNP beta of at least
Note that the beta of a transistor drops off with collector
current. Therefore, make sure the beta at I
minimum requirement.
For cases where the adapter voltage is low (less than 5.5 V),
calculate the saturation voltage by
where V
protection.
Table 5. PNP Pass Transistor Selection Guide
Vendor
Fairchild
ON Semiconductor®
Philips
ZETEX
4.6V–12V
β
V
INPUT
MIN
CE(SAT)
PROTECT
=
I
= V
MAX
I
Β
is the forward drop of the reverse input
ADAPTER(MIN)
Figure 21. Reverse Input Protection
=
CIN
40
I
MAX
mA
Part Number
FSB6726
NZT45H8
MTB35200
BCP53T1
MMJT9435
BCP51
ZXT10P20DE6
ZXT2M322
FZT549
FMMT549
− V
PROTECT
MAX
with a minimum base drive
RS
IN
CHG
− V
CS
RS
ADP2291
MAX
− V
meets the
BAT
DRV
Package
SuperSOT
SOT223
TSOP-6
SOT223
SOT223
SOT223
SOT23-6
2 mm × 2 mm MLP
SOT223
SOT23
CEO
(5)
(6)
Rev. A | Page 13 of 20
The power handling capability of the PNP pass transistor is
another important parameter. The maximum power dissipation
of the pass transistor is estimated using
where V
V
Note that the adapter voltage can be either preregulated or
unregulated. In the preregulated case, the difference between
the maximum and minimum adapter voltage is small. In this
case, use the maximum regulated adapter voltage to determine
the maximum power dissipation. In the unregulated case, the
adapter voltage can have a wide range specified. However, the
maximum voltage specified is usually with no load applied.
Therefore, the worst-case power dissipation calculation often
leads to an over-specified pass device. In either case, it is best to
determine the load characteristics of the adapter to optimize the
charger design.
For example:
A guide for selecting the PNP pass transistor is shown in Table 5.
BAT
P
V
V
I
V
V
V
β
V
= 5.0 V − 0.2 V − 0.15 V − 4.2 V
= 0.45 V
P
= 0.50 A × (6.0 V − 0.2 V − 0.15 V − 2.8 V)
= 1.4 W
= 2.8 V, the lowest cell voltage where fast charge can occur.
MAX
DISS
MIN
DISS
ADAPTER(MIN)
ADAPTER(MAX)
PROTECT
ADJ
RS
CE(SAT)
RS
= 150 mV
Max PD @ 25°C
0.5 W
1.5 W
0.625 W
1.5 W
1.6 W
1.3 W
1.1 W
1.5 W
2 W
0.5 W
(W) = I
= 500 mA
=
(W) = I
= 3 V
= 50 mV to 150 mV at V
I
= V
MAX
= 0.2 V at 500 mA
I
Β
ADAPTER(MIN)
MAX
= 5.0 V
MAX
=
= 6.0 V
500
× (V
40
× (V
mA
mA
ADAPTER(MAX)
ADAPTER(MAX)
− V
=
Beta @ 1 A
150
110
200
35
200
270
270
130
130
50
PROTECT
12
5 .
ADJ
− V
− V
− V
= 1.5 V to 3.0 V,
PROTECT
PROTECT
RS
− V
VCE (SAT)
0.5 V
0.1 V
0.175 V
0.3 V
0.18 V
0.5 V
0.17 V
0.17 V
0.25 V
0.25 V
− V
BAT
− V
RS
ADP2291
RS
− V
− V
BAT
BAT
) (7)
)