MAX8663ETL+ Maxim Integrated Products, MAX8663ETL+ Datasheet - Page 23

• Manufacturer Part Number: MAX8663ETL+
• Description: IC POWER MANAGE 40-TQFN-EP
• Manufacturer: Maxim Integrated Products

Specifications of MAX8663ETL+

• Applications: Handheld/Mobile Devices
• Current - Supply: 900µA
• Voltage - Supply: 4.1 V ~ 8 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 40-TQFN Exposed Pad
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

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•
Figure 3. SYS Voltage and Charge Current vs. DC and BAT Voltage
(SYS OVERLOAD)
Thermal Limiting: The input limiter includes a ther-
mal-limiting circuit that reduces the current drawn
from DC when the IC junction temperature increases
beyond +100°C in an attempt to prevent further
heating. The current limit is be reduced by 5%/°C for
temperatures above +100°C, dropping to 0mA at
+120°C. Due to the adaptive nature of the charging
circuitry, the charger current reduces to 0mA before
the system load is affected by thermal limiting.
Adaptive Battery Charging: While the system is
powered from DC, the charger can also draw
power from SYS to charge the battery. If the charg-
er load plus system load exceeds the current capa-
bility of the input source, an adaptive charger
control loop reduces charge current to prevent the
SYS voltage from collapsing. Maintaining a higher
SYS voltage improves efficiency and reduces
power dissipation in the input limiter by running the
switching regulators at lower current.
(CHARGER OFF)
(CHARGER ON)
(CHARGE ON)
BAT CHARGE
CURRENT
SYS
SYS
SYS
BAT
DC
Single-Cell, Li+ Battery-Operated Devices
______________________________________________________________________________________
5.3V
5.0V
4.0V
3.9V
475mA
100mV
550mV
I
SYS
x 150mΩ
100mV
Power-Management ICs for
CHARGER: R
INPUT: 500mA USB
I
SYS
ISET
Figure 3 shows the SYS voltage and its relationship to
DC and BAT under three conditions:
a) Charger is off and SYS is driven from DC.
b) Charger is on and adaptive charger control is limiting
c) The load at SYS is greater than the available input current.
The adaptive battery-charger circuit reduces charging
current when the SYS voltage drops 550mV below DC.
For example, if DC is at 5V, the charge current reduces
to prevent SYS from dropping below 4.45V. When DC is
greater than 5.55V, the adaptive charging circuitry
reduces charging current when SYS drops 300mV
below the 5.3V SYS regulation point (5.0V). Finally, the
circuit prevents itself from pulling SYS down to within
100mV of BAT.
x 30mΩ
0mA
= 3.112kΩ (750mA)
charge current.
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