MAX1508ZETA+T Maxim Integrated Products, MAX1508ZETA+T Datasheet - Page 8

• Manufacturer Part Number: MAX1508ZETA+T
• Description: IC BATT CHARGER LI-ION 8-TDFN
• Manufacturer: Maxim Integrated Products

Specifications of MAX1508ZETA+T

• Function: Charge Management
• Battery Type: Lithium-Ion (Li-Ion)
• Voltage - Supply: 4.25 V ~ 13 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 8-WDFN Exposed Pad
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Connect a ceramic capacitor from BATT to GND for
proper stability. Use a 1µF X5R ceramic capacitor for
most applications.
Connect a 1µF ceramic capacitor from IN to GND. Use
a larger input bypass capacitor for high input voltages
or high charging currents to reduce supply noise.
Connect a 0.47µF ceramic capacitor from VL to GND.
The MAX1508 is in a thermally enhanced thin DFN pack-
age with exposed paddle. Connect the exposed paddle
of the MAX1508 to a large copper ground plane to pro-
vide a thermal contact between the device and the circuit
board. The exposed paddle transfers heat away from the
device, allowing the MAX1508 to charge the battery with
maximum current, while minimizing the increase in die
temperature.
The MAX1508 operates from well-regulated DC
sources. The full-charging input voltage range is 4.25V
to 7V. The device can stand up to 13V on the input
without damage to the IC. If V
the MAX1508 stops charging.
An appropriate power supply must provide at least
4.25V when sourcing the desired peak charging cur-
rent. It also must stay below 6.5V when unloaded.
The MAX1508 provides a complete Li+ charging solu-
tion. The Typical Operating Circuit at the end of the
data sheet shows the MAX1508 as a stand-alone Li+
battery charger. The 2.8kΩ resistor connected to ISET
sets a charging current of 520mA. The LED indicates
when either fast-charge or precharge qualification has
begun. When the battery is full, the LED turns off.
Linear Li+ Battery Charger with Integrated Pass FET,
Thermal Regulation, and ACOK in 3mm x 3mm TDFN
Table 1. CHG States
X = Don’t care.
*I
8
(MAX1508/MAX1508Z)
FAST
_______________________________________________________________________________________
is reduced as necessary to maintain the die temperature at +100°C.
High
Low
Low
Low
Low
EN
X
(MAX1508Y)
Thermal Considerations
High
High
High
High
Low
EN
X
Stand-Alone Li+ Charger
IN
Capacitor Selection
Application Circuits
is greater than 7V, then
DC Input Sources
4.25V ≤ V
4.25V ≤ V
4.25V ≤ V
V
>7V
V
BATT
X
IN
IN
IN
IN
≤ 7V
≤ 7V
≤ 7V
V
< 2.5V
≥ 2.5V
4.2V
BATT
V
Figure 3 shows the MAX1508 as a µP-cooperated Li+
battery charger. The MAX1508 and MAX1508Z start
charging the battery when EN is low. The µP can drive
EN high to disable the charger (MAX1508 and
MAX1508Z). The MAX1508’s ACOK output indicates
the presence of a valid AC adapter to the µP. CHG can
be used to detect the charge status of a battery. By
monitoring V
current.
The universal serial bus (USB) provides a high-speed
serial communication port as well as power for the
remote device. The MAX1508 can be configured to
charge its battery at the highest current possible from
the host port. Figure 4 shows the MAX1508 as a USB
battery charger. To make the circuit compatible with
either 100mA or 500mA USB ports, the circuit initializes
at 95mA charging current. The microprocessor then
interrogates the host to determine its current capability.
If the host port is capable, the charging current is
increased to 435mA. The 435mA current was chosen to
avoid exceeding the 500mA USB specification.
Connect a 1µF ceramic input capacitor as close to the
device as possible. Provide a large copper GND plane
to allow the exposed paddle to sink heat away from the
device. Connect the battery to BATT as close to the
device as possible to provide accurate battery voltage
sensing. Make all high-current traces short and wide to
minimize voltage drops. For an example layout, refer to
the MAX1507/MAX1508 evaluation kit layout.
TRANSISTOR COUNT: 1812
PROCESS: BiCMOS
X
X
IN
10% of I
10% of I
ISET
I
I
FAST
BATT
0
0
0
, the system can measure the charge
FAST
FAST
*
Microprocessor-Interfaced Charger
CHG
Layout and Bypassing
Hi-Z
Hi-Z
Hi-Z
Hi-Z
USB-Powered Li+ Charger
Low
Low
Chip Information
Shutdown
Prequalification
Fast Charge
Full Charge
Overvoltage
Disabled
STATE