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MAX8814ETA+T

P1-P3P4-P6P7-P9P10-P11
MAX8814
28V Linear Li+ Battery Charger
with Smart Autoboot Assistant
Maxim Integrated | 4www.maximintegrated.com
Package Information (continued)
(V
IN
= 5V, V
BATT
= 4V, R
POK
= 1MΩ to BATT, EN = 0V, R
ISET
= 2.8kΩ to GND, C
BATT
= 2.2µF, T
A
= -40°C to +85°C, unless other-
wise noted. Typical values are at T
A
= +25°C.)
0
300
200
100
500
400
900
800
700
600
1000
0 4 8 12 16 20 24 28
CHARGE CURRENT
vs. INPUT VOLTAGE
MAX8814 toc04
INPUT VOLTAGE (V)
CHARGE CURRENT (mA)
0
300
200
100
400
500
600
700
800
900
1000
0 200100 300 400 500
CHARGE CURRENT vs. INPUT
VOLTAGE HEADROOM
MAX8814 toc05
V
IN
- V
BATT
(mV)
CHARGE CURRENT (mA)
V
BATT
= 4V
V
IN
RISING
40
μs/div
STARTUP INTO PRECHARGE
100mA/div
MAX8814 toc06
0A
5V/div
5V/div
5V/div
0V
0V
0V
I
BATT
V
IN
V
EN
V
POK
V
BATT
= 2V
100μs/div
SHUTDOWN
(FAST-CHARGE TO SHUTDOWN)
500mA/div
MAX8814 toc07
0A
0V
5V/div
5V/div
5V/div
0V
0V
I
BATT
V
IN
V
EN
V
POK
CHARGE CURRENT vs. R
ISET
MAX8814 toc09
R
ISET
(kΩ)
CHARGE CURRENT (mA)
100010010
10
100
1000
1
1 10,000
0
200
100
400
300
600
500
700
-40 10-15 356085
CHARGE CURRENT vs. AMBIENT
TEMPERATURE
MAX8814 toc10
TEMPERATURE (°C)
CHARGE CURRENT (mA)
R
ISET
= 2.8kΩ
V
BATT
= 4V
V
BATT
= 3.2V
4μs/div
AUTOBOOT ENABLED
BY ABI SIGNAL
MAX8814 toc11
0V
0V
5V/div
5V/div
5V/div
5V/div
0V
0V
V
ABI
V
IN
V
BATT
V
ABO
4μs/div
AUTOBOOT ENABLED
BY INPUT SUPPLY
MAX8814 toc12
0V
5V/div
0V
5V/div
5V/div
5V/div
0V
0V
V
ABI
V
IN
V
BATT
V
ABO
MAX8814
28V Linear Li+ Battery Charger
with Smart Autoboot Assistant
Maxim Integrated | 5www.maximintegrated.com
Pin Description
PIN NAME FUNCTION
1IN
Input Supply Voltage. Bypass IN to GND with a 1µF or larger ceramic capacitor to minimize line noise
and maximize input transient rejection.
2 GND
Ground. Connect GND and the exposed paddle to a large copper ground plane for maximum power
dissipation. Connect GND to the exposed paddle directly under the IC.
3 ISET
Charge-Current Program and Fast-Charge Current Monitor. Output current from ISET is 877.2µA per
ampere of battery charging current. Set the charging current by connecting a resistor (R2 in Figure 3)
from ISET to GND. I
FAST-CHARGE
= 1596V / R
ISET
. To configure the MAX8814 as a USB charger, see
Figure 4.
4 ABI
Autobooting External Input. See the Autobooting Assistant section and Table 1 for autobooting
conditions. ABI is pulled to GND through an internal 200kΩ resistor.
5 ABO
Autobooting Logic Output. See the Autobooting Assistant section and Table 1 for autobooting
conditions.
6 EN
Logic-Level Enable Input. Drive EN high to disable charger. Drive EN low or leave unconnected for
normal operation. EN has an internal 200kΩ pulldown resistor.
7 POK
Input-Voltage Status Indicator. Connect a 1MΩ pullup resistor from POK to an external system supply.
POK is an open-drain output that asserts low when V
IN
> 4.25V and (V
IN
- V
BATT
) ≥ 40mV. If V
BATT
≥
(V
IN
- 40mV), the IC is shut down and POK becomes high impedance.
8 BATT Battery Connection. Bypass BATT to GND with a minimum of 2.2µF of capacitor.
—EP
Exposed Paddle. Connect the exposed paddle to a large ground plane for maximum power
dissipation. Connect GND to the exposed paddle directly under the IC.
MAX8814
28V Linear Li+ Battery Charger
with Smart Autoboot Assistant
Maxim Integrated | 6www.maximintegrated.com
Detailed Description
The MAX8814 charger uses voltage, current, and ther-
mal-control loops to charge a single Li+ cell and pro-
tect the battery (Figure 1). When a Li+ battery with a
cell voltage below 2.5V is inserted, the MAX8814
charger enters the prequalification stage where it
precharges that cell with 10% of the user-programmed
fast-charge current (Figure 2). When the battery voltage
exceeds 2.5V, the charger soft-starts as it enters the
fast-charge stage. In the MAX8814, the fast-charge
current level is programmed through a resistor from
ISET to GND. As the battery voltage approaches 4.2V,
the charging current is reduced. Once the battery volt-
age reaches 4.2V, the IC then enters a constant voltage
regulation mode to maintain the battery at full charge.
Thermal Regulation
The thermal-regulation loop limits the MAX8814 die
temperature to +115°C by reducing the charge current
as necessary. This feature not only protects the IC from
overheating, but also allows a higher charge current
without risking damage to the IC.
OUTPUT DRIVER,
CURRENT SENSE,
AND LOGIC
TEMPERATURE
SENSOR
VL
REGULATOR
REF
REFOK
V
IN
OVLO
VL
UVLO
V
REF
V
REF
LOGIC
BATT
ISET
ABI
ABO
EN
POK
IN
BATT
IN
BATT
POK
200kΩ
GND
EP
+115°C
Li+
C3
2.2μF
V
I/O
200kΩ
C1
1μF
R2
2.8kΩ
4.25V TO 28V
R3
1MΩ
MAX8814
V
L
V
REF
Figure 1. Functional Diagram
P1-P3P4-P6P7-P9P10-P11

MAX8814ETA+T

Mfr. #:
Buy MAX8814ETA+T
Manufacturer:
Maxim Integrated
Description:
Battery Management 28V Linear Li+ Battery Charger
Lifecycle:
New from this manufacturer.
Delivery:
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