MAX1925ETC+ Maxim Integrated Products, MAX1925ETC+ Datasheet - Page 11

• Manufacturer Part Number: MAX1925ETC+
• Description: IC CHARGER LI+ 12-TQFN
• Manufacturer: Maxim Integrated Products

Specifications of MAX1925ETC+

• Function: Charge Management
• Battery Type: Lithium-Ion (Li-Ion)
• Voltage - Supply: 4.5 V ~ 12 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 12-TQFN Exposed Pad
• Product: Charge Management
• Operating Supply Voltage: 4.25 V to 12 V
• Supply Current: 39 uA
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• Charge Safety Timers: Yes
• Mounting Style: SMD/SMT
• Temperature Monitoring: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Figure 3. Charging Current and Voltage Timing Diagrams
linear 4mA current source (PREQUAL1). When the cell
voltage exceeds 2V, the cell is charged with 10% of the
programmed fast-charge current (I
reaches 3V. When the cell voltage is above 3V, fast
charging occurs at the full set current. If the cell fails to
reach the next prequalification threshold before a set
time (see t
Capacitor and Fault Modes section), charging stops, a
fault alarm is set, and the CHG output blinks.
Figures 2 and 3 show charging behavior typical Li+ cell.
The MAX1925/MAX1926 remain in fast-charge mode
until the battery voltage reaches regulation and the
PREQUAL1
______________________________________________________________________________________
4V
3V
2V
1V
4V
3V
2V
1V
t
PREQUAL1
and t
4mA
= t/1024
FAULT
PREQUAL2
PREQUAL1
t
FULL TOPOFF
PREQUAL2
Switch-Mode 1-Cell Li+ Chargers
FASTCHG
= t/16
C/10
NORMAL VOLTAGE
PROFILE
PREQUAL2
in the Timer
FASTCHG
) until it
C/8
CHARGE TIME (t
CHARGE CURRENT
CHG LED OFF
CCM
FULLCHG
charge current drops below 1/8th of I
charger then enters full topoff mode and the CHG LED
is turned off. In full topoff mode, the controller continues
to operate as in fast-charge mode, except that it
remains in constant-voltage mode (CVM) unless the bat-
tery voltage falls. After every t
Capacitor and Fault Modes section) the charger enters
the Kelvin state (for 2 CT clock cycles, 60ms with C
100nF) where charge current is interrupted so that the
battery voltage can be accurately measured.
The MAX1925/MAX1926 do not enter done mode until
t
= 3 HOURS WITH C
FULLCHG
CURRENT
CHG LED OFF
NORMAL
PROFILE
CT
has been reached. If the battery is removed
= 100nF)
CVM
FASTCHG
4.2V
CVM
C
FAULT
CCM
PREQUAL1
t
C
C/8
C/10
2mA
FASTCHG
(see the Timer
. The
CT
11
=