MAX6841IUKD1+T Maxim Integrated, MAX6841IUKD1+T Datasheet - Page 11

• Manufacturer Part Number: MAX6841IUKD1+T
• Description: Supervisory Circuits
• Manufacturer: Maxim Integrated
• Series: MAX6841, MAX6842, MAX6843, MAX6844, MAX6845r

Specifications of MAX6841IUKD1+T

• Number Of Voltages Monitored: 1
• Monitored Voltage: 0.9 V to 1.5 V
• Undervoltage Threshold: 1.35 V
• Overvoltage Threshold: 1.425 V
• Output Type: Active High, Active Low, Push-Pull
• Manual Reset: Resettable
• Watchdog: No Watchdog
• Battery Backup Switching: No Backup
• Power-up Reset Delay (typ): 2 ms
• Supply Voltage - Max: 1.8 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Package / Case: SOT-23
• Chip Enable Signals: No
• Maximum Power Dissipation: 571 mW
• Minimum Operating Temperature: - 40 C
• Power Fail Detection: No
• Supply Current (typ): 8.1 uA
• Supply Voltage - Min: 0.75 V

Figure 5. Charge-Current Fault
Set the nominal values of the trickle charge current by
selecting resistor R
where V
the battery-pack voltage, and I
current.
When the trickle-charge option is not used, float CGO
and connect TKO to the gate of the overcharge protec-
tion MOSFET (see Figure 9). When a charger is applied
and the voltage on one or more cells is less than
V
put until all cells exceed V
All three external MOSFETs have their source pins con-
nected to the SRC pin. When a MOSFET is turned off, FET
drivers pull the gate to the SRC voltage. Additional exter-
nal pullup resistors are not needed. When the MOSFET is
turned on, the V
built in the drivers. This allows use of MOSFETs with maxi-
mum V
ry and drive capability. The quiescent current in normal
operation is less than 3µA per driver.
UV_TH
GS
, the MAX1894/MAX1924 modulate the TKO out-
CHRG
of -20V. All three drivers have the same circuit-
R
TKO
is the charger output voltage, V
NO
NO
GS
______________________________________________________________________________________
TKO
= (V
is limited to -14V by a clamp circuit
Advanced Li+ Battery-Pack Protectors
CHRG
NORMAL OPERATION
based on the following equation:
V
V
B4P
RSENSE
TKO, CGO = H
UV_TH
OC FAULT
Protection FET Drivers
FOR 3ms
> V
SRC
< V
- VP
YES
OC_TH
+ 0.1V
TKO
.
ACK
is the trickle-charge
)/I
TKO
YES
PACK
is
All current faults are detected using a current-sense
resistor connected between BN and PKN. The value of
this resistor sets the fault current levels. Charge-current
fault is given by:
Discharge-current fault is given by:
Pack-short current fault is given by:
Select R
For example, a 20mΩ R
fault at 5A. Choose an R
dissipation during normal operation and current fault
conditions. For example, pack-short current is given by:
Figure 6. Discharge-Current Fault
SENSE
I
I
OD TH
OC TH
I
PS TH
_
NO
_
_
NO
to obtain the desired fault current levels.
=
=
=
V
R
V
R
R
V
OC TH
OC TH
SENSE
NORMAL OPERATION
PS TH
SENSE
SENSE
DSO, TKO, CGO = H
V
V
SRC
RSENSE
SENSE
_
_
_
SENSE
OD FAULT
FOR 3ms
> V
B4P
> V
YES
=
=
=
OD_TH
+ 0.1V
R
R
R
sets the charge current
145
100
405
that can withstand the
R
SENSE
SENSE
SENSE
SENSE
mV
mV
mV
YES
Selection
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