Datasheet

MAX8814
28V Linear Li+ Battery Charger with
Smart Autoboot Assistant
4 _______________________________________________________________________________________
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
-1.0
-0.4
-0.6
-0.8
-0.2
0
0.2
0.4
0.6
0.8
1.0
-40 10-15 35 60 85
BATTERY REGULATION VOLTAGE
ACCURACY vs. AMBIENT TEMPERATURE
MAX8814 toc08
TEMPERATURE (
°
C)
BATTERY REGULATION VOLTAGE ACCURACY (%)
I
BATT
= 0A
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
Typical Operating Characteristics (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.)