MAX745EAP Maxim Integrated Products, MAX745EAP Datasheet - Page 5
![IC BATTERY CHARGER LI-ION 20SSOP](/photos/1/39/13938/175-20-ssop_sml.jpg)
MAX745EAP
Manufacturer Part Number
MAX745EAP
Description
IC BATTERY CHARGER LI-ION 20SSOP
Manufacturer
Maxim Integrated Products
Datasheet
1.MAX745EAP.pdf
(8 pages)
Specifications of MAX745EAP
Function
Charge Management
Battery Type
Lithium-Ion (Li-Ion)
Voltage - Supply
6 V ~ 24 V
Operating Temperature
-40°C ~ 85°C
Mounting Type
Surface Mount
Package / Case
20-SSOP
Output Voltage
5.4 V
Operating Supply Voltage
6 V to 24 V
Supply Current
4 mA
Maximum Operating Temperature
+ 85 C
Minimum Operating Temperature
- 40 C
Mounting Style
SMD/SMT
Case
SSOP
Dc
02+
Lead Free Status / RoHS Status
Contains lead / RoHS non-compliant
Other names
146982B
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Company:
Part Number:
MAX745EAP
Manufacturer:
MAXIM
Quantity:
1 000
Company:
Part Number:
MAX745EAP
Manufacturer:
MAXIM
Quantity:
14
Company:
Part Number:
MAX745EAP+T
Manufacturer:
AD
Quantity:
1 140
The MAX745 is a switch-mode, Li+ battery charger that
can achieve 90% efficiency. The charge voltage and
current are set independently by external resistor-
dividers at SETI and VADJ, and at pin connections at
CELL0 and CELL1. VADJ is connected to a resistor-
divider to set the charging voltage. The output voltage-
adjustment range is ±5%, eliminating the need for 0.1%
resistors while still achieving 0.75% set accuracy using
1% resistors.
The MAX745 consists of a current-mode, pulse-width-
modulated (PWM) controller and two transconductance
error amplifiers: one for regulating current (GMI) and
the other for regulating voltage (GMV) (Figure 2). The
error amplifiers are controlled through the SETI and
VADJ pins. Whether the MAX745 is controlling voltage
or current at any time depends on the battery state. If
the battery is discharged, the MAX745 output reaches
______________________________________________________________Pin Description
_______________Detailed Description
11, 12
PIN
10
13
14
15
16
17
18
19
20
1
2
3
4
5
6
7
8
9
STATUS
CELL1,
CELL0
NAME
SHDN
PGND
VADJ
BATT
THM/
IBAT
DCIN
GND
CCV
SETI
DLO
REF
BST
CCI
DHI
CS
VL
LX
_______________________________________________________________________________________
Current-Sense Amplifier’s Analog Current-Source Output. See the Monitoring Charge Current section for a
detailed description.
Charger Input Voltage. Bypass DCIN with a 0.1µF capacitor.
Chip Power Supply. Output of the 5.4V linear regulator from DCIN. Bypass VL with a 4.7µF capacitor.
Voltage-Regulation-Loop Compensation Point
Current-Regulation-Loop Compensation Point
Thermistor Sense-Voltage Input. THM/SHDN also performs the shutdown function. If pulled low,
the charger turns off.
4.2V Reference Voltage Output. Bypass REF with a 0.1µF or greater capacitor.
Voltage-Adjustment Pin. VADJ is tied to a 1% tolerance external resistor-divider to adjust the voltage set
point by 10%, eliminating the need for precision 0.1% resistors. The input voltage range is 0V to V
SETI is externally tied to the resistor-divider between REF and GND to set the charging current.
Analog Ground
Logic Inputs to Select Cell Count. See Table 1 for cell-count programming.
An open-drain MOSFET sinks current when in current-regulation mode, and is high impedance when in volt-
age-regulation mode. Connect STATUS to VL through a 1kΩ to 100kΩ pullup resistor. STATUS can also drive
an LED for visual indication of regulation mode (see MAX745 EV kit). Leave STATUS floating if not used.
Battery-Voltage-Sense Input and Current-Sense Negative Input
Current-Sense Positive Input
Power Ground
Low-Side Power MOSFET Driver Output
High-Side Power MOSFET Driver Output
Power Connection for the High-Side Power MOSFET Source
Power Input for the High-Side Power MOSFET Driver
Switch-Mode Lithium-Ion
the current-regulation limit before the voltage limit,
causing the system to regulate current. As the battery
charges, the voltage rises to the point where the volt-
age limit is reached and the charger switches to regu-
lating voltage. The STATUS pin indicates whether the
charger is regulating current or voltage.
To set the voltage limit on the battery, connect a resis-
tor- divider to VADJ from REF. A 0V to V
VADJ sets a ±5% change in the battery limit voltage
around 4.2V. Since the 0 to 4.2V range on VADJ results
in only a 10% change on the voltage limit, the resistor-
divider’s accuracy does not need to be as high as the
output voltage accuracy. Using 1% resistors for the
voltage dividers typically results in no more than 0.1%
degradation in output voltage accuracy. VADJ is inter-
nally buffered so that high-value resistors can be used
to set the output voltage. When the voltage at VADJ is
FUNCTION
Battery Charger
Voltage Control
REF
REF
change at
.
5