MAX8845ZETC+ Maxim Integrated Products, MAX8845ZETC+ Datasheet - Page 8

• Manufacturer Part Number: MAX8845ZETC+
• Description: IC BATT CHRGR LI+ 28V 12TQFN-EP
• Manufacturer: Maxim Integrated Products

Specifications of MAX8845ZETC+

• Function: Charge Management
• Battery Type: Lithium-Ion (Li-Ion)
• Voltage - Supply: 0 V ~ 28 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 12-TQFN Exposed Pad
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

28V Linear Li+ Battery Chargers with Battery
Detection and Overvoltage Protected Output
top-off current threshold set by R
enters top-off mode and the CHG indicator goes high
impedance signaling that the battery is fully charged.
SAFEOUT is a linear regulator that provides an output
voltage of 4.7V (MAX8845Z/MAX8845Y/MAX8845W) or
4.85V (MAX8845X) and can be used to supply low volt-
age- rated USB systems. The SAFEOUT linear regulator
turns on when V
abled when V
old (7.5V typ) (8.0V typ for MAX8845X only).
DETBAT is a battery-pack ID resistor detector that
enables the battery charger if pulled low through a
resistor that is less than 51kΩ. If DETBAT is left uncon-
nected or the pulldown resistor is 51kΩ or greater the
battery charger is disabled. If DETBAT is not used con-
nect DETBAT to GND for normal operation.
The open-drain POK output asserts low when 2.35V ≤
V
40mV (typ V
shutdown. When interfacing with a microprocessor
logic input, a pullup resistor to the microprocessor’s I/O
voltage may be required.
Figure 2. Charge-State Diagram
8
IN
Overvoltage-Protected Output (SAFEOUT)
_______________________________________________________________________________________
≤ 7V (7.5V for MAX8845X only) and (V
Battery-Pack Detection Input (DETBAT)
V
BATT
CONSTANT-CURRENT CHARGE
10% OF IFAST-CHARGE
< 2.4V
100% OF I
IN
V
IN
BATT
FAST-CHARGE
PRECHARGE
CHG = LOW
rising). POK is high impedance during
CHG = LOW
IN
is greater than the overvoltage thresh-
< 2.5V
FAST-CHARGE
≥ 4.25V regardless of EN and is dis-
V
BATT
≥ 2.5V
(V
IN
- V
ANY CHARGING STATE
BATT
I
BATT
) < 30mV
FOR 6.2ms (typ) OR LONGER
(V
> 295V/R
IN
MIN
I
- V
BATT
V
IN
IC ENABLED
BATT
POK Output
< OVP, AND
MIN
≤ I
, the charger
) ≥ 40mV, AND
MIN
IN
(kΩ) - 24mA
DIE TEMPERATURE > +115°C
CHARGER = DISABLED
- V
CHG = HIGH-Z
SHUTDOWN
BATT
4.35 VOLTAGE REGULATION (MAX8845W)
(V
) ≥
(MAX8845Z/MAX8845Y/MAX8845X)
IN
- V
V
IC DISABLED
4.2 VOLTAGE REGULATION
IN
BATT
> OVP, OR
) < 30mV, OR
CHG = HIGH-Z
The MAX8845Z/MAX8845Y/MAX8845X/MAX8845W con-
tain autobooting assistant circuits that generate an
enable signal for system booting (ABO—MAX8845Z,
ABO—MAX8845Y/MAX8845X/MAX8845W). For the
MAX8845Z, the booting assistant functions as an internal
OR gate (Figure 1). The first input is dependant on the
input voltage (V
is an external signal applied to ABI. The first input (POK)
is driven high once DETBAT is pulled low through a
resistor less than 51kΩ, 2.35V ≤ V
MAX8845X), and (V
The second input signal (ABI) is driven by an external
source (Table 1). ABI enables an autoboot signal when
a battery is connected at BATT and is independent of
POK. If POK is pulled low, the booting assistant always
drives ABO high regardless of ABI. ABI is pulled to GND
through an internal 200kΩ resistor. If ABI is supplied
from an outside exposed pin, a RC filter (Figure 4) is
required for ESD protection and noise filtering. If ABI is
supplied by a system’s internal GPIO, or logic, the RC
filter is not required. For the MAX8845Y/MAX8845X/
MAX8845W, the output ABO is only dependent on the
state of ABI (Table 1).
CHG is an open-drain output that indicates charge sta-
tus. Table 2 describes the state of CHG during different
stages of operation. CHG is suitable for driving a charge
indication LED. If the MAX8845Z/MAX8845Y/MAX8845X/
TOP-OFF
IN
) and DETBAT while the second input
CHG Charge Indicator Output
IN
CHARGING CURRENT REDUCTION
CHARGING CURRENT IS REDUCED
- V
THERMAL SHUTDOWN, OR
(V
IN
FROM ANYWHERE
BATT
ASYNCHRONOUS
- V
V
CHARGING STATE
IC DISABLED
IN
BATT
AS NECESSARY
Autobooting Assistant
RETURN TO
> OVP, OR
) ≥ 40mV (typ V
) < 30mV, OR
DIE TEMPERATURE ≤ +115°C
IN
≤ 7V (7.5V for only
IN
rising).