MAX1645AEEI ,Advanced Chemistry-Independent / Level 2 Battery Chargers with Input Current LimitingFeaturesThe MAX1645 are high-efficiency battery chargers capa- Input Current Limitingble of chargi ..
MAX1645AEEI-T ,Advanced-Chemistry-Independent, Level-2 Battery Chargers with Input Current LimitingApplications♦ 3A max Battery Charge CurrentNotebook Computers♦ 6-Bit Charge Current Setting Point-o ..
MAX1645BEEI ,Advanced Chemistry-Independent, Level 2 Battery Charger with Input Current LimitingFeaturesThe MAX1645B is a high-efficiency battery charger Input Current Limitingcapable of chargin ..
MAX1645BEEI ,Advanced Chemistry-Independent, Level 2 Battery Charger with Input Current LimitingELECTRICAL CHARACTERISTICS(Circuit of Figure 1, V = +3.3V, V = +16.8V, V = +18V, T = 0°C to +85°C, ..
MAX1645BEEI ,Advanced Chemistry-Independent, Level 2 Battery Charger with Input Current LimitingApplications 3A (max) Battery Charge CurrentNotebook Computers 6-Bit Charge-Current Setting Point ..
MAX1645BEEI+ ,Advanced Chemistry-Independent, Level 2 Battery Charger with Input Current LimitingApplications♦ 3A (max) Battery Charge CurrentNotebook Computers♦ 6-Bit Charge-Current Setting Point ..
MAX4397DCTM+ ,Audio/Video Switch for Dual SCART ConnectorsELECTRICAL CHARACTERISTICS(V = 12V, V = V = 5V, 0.1µF X5R capacitor in parallel with a 10µF aluminu ..
MAX4397DCTM+T ,Audio/Video Switch for Dual SCART ConnectorsBlock Diagram appears at end of data sheet.____ Maxim Integrated Products 1For pricing, delivery, a ..
MAX4397SCTM ,Audio/Video Switch For Dual SCART ConnectorsFeaturesThe MAX4397 dual SCART switch matrix routes audio♦ Video Outputs Drive 2V into 150ΩP-P and ..
MAX4397SCTM+ ,Audio/Video Switch for Dual SCART ConnectorsFeaturesThe MAX4397 dual SCART switch matrix routes audio♦ Video Outputs Drive 2V into 150ΩP-P and ..
MAX4399CTK ,Audio/Video Switch for Three SCART ConnectorsApplicationsCVBS RGBSTBENCODERSatellite ReceiversTV SCARTR/L AUDIO R/L AUDIO CONNECTORSatellite Set ..
MAX4399CTK+ ,Audio/Video Switch for Three SCART ConnectorsApplicationsRGBCVBSSTBENCODERSatellite ReceiversTV SCARTR/L AUDIOR/L AUDIO CONNECTORSatellite Set-T ..
MAX1645AEEI
Advanced Chemistry-Independent / Level 2 Battery Chargers with Input Current Limiting
General DescriptionThe MAX1645 are high-efficiency battery chargers capa-
ble of charging batteries of any chemistry type. It uses the
Intel System Management Bus (SMBus) to control volt-
age and current charge outputs.
When charging lithium-ion (Li+) batteries, the MAX1645
automatically transition from regulating current to regu-
lating voltage. The MAX1645 can also limit line input
current so as not to exceed a predetermined current
drawn from the DC source. A 175s charge safety timer
prevents “runaway charging” should the MAX1645 stop
receiving charging voltage/ current commands.
The MAX1645 employs a next-generation synchronous
buck control circuity that lowers the minimum input-to-
output voltage drop by allowing the duty cycle to
exceed 99%. The MAX1645 can easily charge one to
four series Li+ cells.
ApplicationsNotebook Computers
Point-of-Sale Terminals
Personal Digital Assistants
FeaturesInput Current Limiting175s Charge Safety Timeout128mA Wake-Up ChargeCharges Any Chemistry Battery: Li+, NiCd,
NiMH, Lead Acid, etc.Intel SMBus 2-Wire Serial InterfaceCompliant with Level 2 Smart Battery Charger
Spec Rev. 1.0+8V to +28V Input Voltage RangeUp to 18.4V Battery Voltage11-Bit Battery Voltage Setting±0.8% Output Voltage Accuracy with Internal
Reference3A max Battery Charge Current6-Bit Charge Current Setting 99.99% max Duty Cycle for Low-Dropout OperationLoad/Source Switchover Drivers>97% Efficiency
MAX1645/MAX1645A
Advanced Chemistry-Independent, Level 2
Battery Chargers with Input Current Limiting19-1566; Rev 2; 1/01
Typical Operating Circuit appears at end of data sheet.SMBus is a trademark of Intel Corp.
Pin ConfigurationOrdering Information
MAX1645/MAX1645A
Advanced Chemistry-Independent, Level 2
Battery Chargers with Input Current Limiting
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS(Circuit of Figure 1, VDD= +3.3V, VBATT= +16.8V, VDCIN= +18V, TA
= 0°C to +85°C, unless otherwise noted. Typical values are at= +25°C.)
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
DCIN, CVS, CSSP, CSSN, LX to GND....................-0.3V to +30V
CSSP to CSSN, CSIP to CSIN...............................-0.3V to +0.3V
PDS, PDL to GND...................................-0.3V to (VCSSP+ 0.3V)
BST to LX..................................................................-0.3V to +6V
DHI to LX...................................................-0.3V to (VBST+ 0.3V)
CSIP, CSIN, BATT to GND.....................................-0.3V to +22V
LDO to GND.....................-0.3V to (lower of 6V or VDCIN+ 0.3V)
DLO to GND...........................................-0.3V to (VDLOV+ 0.3V)
REF, DAC, CCV, CCI, CCS, CLS to GND.....-0.3V to (VLDO+ 0.3V)
VDD, SCL, SDA, INT, DLOV to GND.........................-0.3V to +6V
THM to GND...............................................-0.3V to (VDD+ 0.3V)
PGND to GND.......................................................-0.3V to +0.3V
LDO Continuous Current.....................................................50mA
Continuous Power Dissipation (TA= +70°C)
28-Pin QSOP (derate 10.8mW/°C above +70°C).........860mW
Operating Temperature Range...........................-40°C to +85°C
Storage Temperature.........................................-60°C to +150°C
Lead Temperature (soldering, 10s).................................+300°C
MAX1645/MAX1645A
Advanced Chemistry-Independent, Level 2
Battery Chargers with Input Current Limiting
ELECTRICAL CHARACTERISTICS (continued)(Circuit of Figure 1, VDD= +3.3V, VBATT= +16.8V, VDCIN= +18V, TA
= 0°C to +85°C, unless otherwise noted. Typical values are at= +25°C.)
MAX1645/MAX1645A
Advanced Chemistry-Independent, Level 2
Battery Chargers with Input Current Limiting
ELECTRICAL CHARACTERISTICS (continued)(Circuit of Figure 1, VDD= +3.3V, VBATT= +16.8V, VDCIN= +18V, TA
= 0°C to +85°C, unless otherwise noted. Typical values are at= +25°C.)
MAX1645/MAX1645A
Advanced Chemistry-Independent, Level 2
Battery Chargers with Input Current Limiting
ELECTRICAL CHARACTERISTICS (continued)(Circuit of Figure 1, VDD= +3.3V, VBATT= +16.8V, VDCIN= +18V, TA
= 0°C to +85°C, unless otherwise noted. Typical values are at= +25°C.)
ELECTRICAL CHARACTERISTICS(Circuit of Figure 1, VDD= +3.3V, VBATT= +16.8V, VDCIN= +18V, TA
= -40°C to +85°C, unless otherwise noted. Guaranteed by design.)
MAX1645/MAX1645A
Advanced Chemistry-Independent, Level 2
Battery Chargers with Input Current Limiting
ELECTRICAL CHARACTERISTICS (continued)
(Circuit of Figure 1, VDD= +3.3V, VBATT= +16.8V, VDCIN= +18V, TA
= -40°C to +85°C, unless otherwise noted. Guaranteed by design.)
MAX1645/MAX1645A
Advanced Chemistry-Independent, Level 2
Battery Chargers with Input Current Limiting
ELECTRICAL CHARACTERISTICS (continued)
(Circuit of Figure 1, VDD= +3.3V, VBATT= +16.8V, VDCIN= +18V, TA
= -40°C to +85°C, unless otherwise noted. Guaranteed by design.)
MAX1645/MAX1645A
Advanced Chemistry-Independent, Level 2
Battery Chargers with Input Current Limiting
Typical Operating Characteristics
(Circuit of Figure 1, VDCIN= 20V, TA = +25°C, unless otherwise noted.)
ELECTRICAL CHARACTERISTICS (continued)
(Circuit of Figure 1, VDD= +3.3V, VBATT= +16.8V, VDCIN= +18V, TA= -40°C to +85°C, unless otherwise noted. Guaranteed by design.)
Note 1:Guaranteed by meeting the SMB timing specs.
Note 2:The charger reverts to a trickle-charge mode of ICHARGE= 128mA below this threshold.
Note 3:Does not include current-sense resistor tolerance.
Note 4:Voltage difference between CCV, and CCI or CCS when one of these three pins is held low and the others try to pull high.
MAX1645/MAX1645A
Advanced Chemistry-Independent, Level 2
Battery Chargers with Input Current Limiting
Typical Operating Characteristics (continued)
(Circuit of Figure 1, VDCIN= 20V, TA = +25°C, unless otherwise noted.)
MAX1645/MAX1645A
Advanced Chemistry-Independent, Level 2
Battery Chargers with Input Current Limiting
Pin Description
MAX1645/MAX1645A
Advanced Chemistry-Independent, Level 2
Battery Chargers with Input Current Limiting
Detailed Description
The MAX1645/MAX1645A consist of current-sense
amplifiers, an SMBus interface, transconductance
amplifiers, reference circuitry, and a DC–DC converter
(Figure 2). The DC–DC converter generates the control
signals for the external MOSFETs to maintain the volt-
age and the current set by the SMBus interface. The
MAX1645/MAX1645A feature a voltage-regulation loop
and two current-regulation loops. The loops operate
independently of each other. The voltage-regulation
loop monitors BATT to ensure that its voltage never
exceeds the voltage set point (V0). The battery current-
regulation loop monitors current delivered to BATT to
ensure that it never exceeds the current-limit set point
(I0). The battery current-regulation loop is in control as
long as BATT voltage is below V0. When BATT voltage
reaches V0, the current loop no longer regulates. A
third loop reduces the battery-charging current when
the sum of the system (the main load) and the battery
charger input current exceeds the charging source cur-
rent limit.
Setting Output Voltage
The MAX1645/MAX1645A voltage DACs have a 16mV
LSB and an 18.432V full scale. The SMBus specifica-
tion allows for a 16-bit ChargingVoltage() command
that translates to a 1mV LSB and a 65.535V full-scale
voltage; therefore, the ChargingVoltage() value corre-
sponds to the output voltage in millivolts. The
MAX1645/MAX1645A ignore the first four LSBs and use
the next 11 LSBs to control the voltage DAC. All codes
greater than or equal to 0b0100 1000 0000 0000
(18432mV) result in a voltage overrange, limiting the
charger voltage to 18.432V. All codes below 0b0000
0100 0000 0000 (1024mV) terminate charging.
Setting Output Current
The MAX1645/MAX1645A current DACs have a 64mA
LSB and a 3.008A full scale. The SMBus specification
allows for a 16-bit ChargingCurrent() command that
translates to a 1mA LSB and a 65.535A full-scale cur-
rent; the ChargingCurrent() value corresponds to the
charging voltage in milliamps. The MAX1645/
MAX1645A drop the first six LSBs and use the next
six LSBs to control the current DAC. All codes above
0b00 1011 1100 0000 (3008mA) result in a current
overrange, limiting the charger current to 3.008A. All
codes below 0b0000 0000 1000 0000 (128mA) turn the
charging current off. A 50mΩsense resistor (R2 in
Figure 1) is required to achieve the correct CODE/cur-
rent scaling.
Input Current Limiting
The MAX1645/MAX1645A limit the current drawn by the
charger when the load current becomes high. The
devices limit the charging current so the AC adapter
voltage is not loaded down. An internal amplifier, CSS,
compares the voltage between CSSP and CSSN to the
voltage at CLS/20. VCLSis set by a resistor-divider
between REF and GND.
The input source current is the sum of the device cur-
rent, the charge input current, and the load current. The
device current is minimal (6mA max) in comparison to
the charge and load currents. The charger input cur-
rent is generated by the DC-DC converter; therefore, the
actualsource current required is determined as follows:
ISOURCE= ILOAD+ [(ICHARGE·VBATT)/ (VIN·η)]
where ηis the efficiency of the DC-DC converter (typi-
cally 85% to 95%).
VCLSdetermines the threshold voltage of the CSS com-
parator. R3 and R4 (Figure 1) set the voltage at CLS.
Sense resistor R1 sets the maximum allowable source
current. Calculate the maximum current as follows:
IMAX= VCLS/ (20 ·R1)
(Limit VCSSP - VCSSNto between 102.4mV and
204.8mV.)
The configuration in Figure 1 provides an input current
limit of:
IMAX= (2.048V / 20) / 0.04Ω= 2.56A
LDO Regulator
An integrated LDO regulator provides a +5.4V supply
derived from DCIN, which can deliver up to 15mA of
current. The LDO sets the gate-drive level of the NMOS
switches in the DC-DC converter. The drivers are actu-
ally powered by DLOV and BST, which must be con-
nected to LDO through a lowpass filter and a diode as
shown in Figure 1. See also the MOSFET Driverssec-
tion. The LDO also supplies the 4.096V reference and
most of the control circuitry. Bypass LDO with a 1µF
capacitor.
VDDSupply
This input provides power to the SMBus interface and
the thermistor comparators. Typically connect VDDto
LDO or, to keep the SMBus interface of the
MAX1645/MAX1645A active while the supply to DCIN is
removed, connect an external supply to VDD.
MAX1645/MAX1645A
Advanced Chemistry-Independent, Level 2
Battery Chargers with Input Current Limiting
Figure 1. Typical Application Circuit
MAX1645/MAX1645A
Advanced Chemistry-Independent, Level 2
Battery Chargers with Input Current Limiting
Figure 2. Functional Diagram
MAX1645/MAX1645A
Advanced Chemistry-Independent, Level 2
Battery Chargers with Input Current Limiting
Operating Conditions
The MAX1645/MAX1645A change their operation
depending on the voltages at DCIN, BATT, VDD,and
THM. Several important operating states follow:AC Present.When DCIN is > 7.5V, the battery is
considered to be in an AC Present state. In this con-
dition, both the LDO and REF will function properly
and battery charging is allowed. When AC is pre-
sent, the AC_PRESENT bit (bit 15) in the
ChargerStatus() register is set to “1.”Power Fail.When DCIN is < BATT + 0.3V, the part is
in the Power Fail state, since the charger doesn’t
have enough input voltage to charge the battery. In
Power Fail, the PDS input PMOS switch is turned off
and the POWER_FAIL bit (bit 13) in the
ChargerStatus() register is set to “1.”Battery Present.When THM is < 91% of VDD, the
battery is considered to be present. The MAX1645/
MAX1645A use the THM pin to detect when a battery
is connected to the charger. When the battery is pre-
sent, the BATTERY_PRESENT bit (bit 14) in the
ChargerStatus() register is set to “1” and charging
can proceed. When the battery is not present, all of
the registers are reset. With no battery present, the
charger will perform a "Float" charge to minimize
contact arcing on battery connection. "Float" charge
will still try to regulate the BATT pin voltage at 18.32V
with 128mA of current compliance.Battery Undervoltage.When BATT < 2.5V, the bat-
tery is in an undervoltage state. This causes the
charger to reduce its current compliance to 128mA.
The content of the ChargingCurrent() register is unaf-
fected and, when the BATT voltage exceeds 2.7V,
normal charging resumes. ChargingVoltage() is unaf-
fected and can be set as low as 1.024V.VDDUndervoltage.When VDD< 2.5V, the VDDsup-
ply is in an undervoltage state, and the SMBus inter-
face will not respond to commands. Coming out of
the undervoltage condition, the part will be in its
Power-On Reset state. No charging will occur when
VDDis under voltage.
SMBus Interface
The MAX1645/MAX1645A receive control inputs from
the SMBus interface. The serial interface complies with
the SMBus specification (refer to the System
Management Bus Specification from Intel Corporation).
Charger functionality complies with the Intel/Duracell
Smart Charger Specification for a Level 2 charger.
The MAX1645/MAX1645A use the SMBus Read-Word
and Write-Word protocols to communicate with the bat-
tery being charged, as well as with any host system
that monitors the battery-to-charger communications as
a Level 2 SMBus charger. The MAX1645/MAX1645A
are SMBus slave devices and do not initiate communi-
cation on the bus. They receive commands and
respond to queries for status information. Figure 3
shows examples of the SMBus Write-Word and Read-
Word protocols, and Figures 4 and 5 show the SMBus
serial-interface timing.
Each communication with these parts begins with the
MASTER issuing a START condition that is defined as a
falling edge on SDA with SCL high and ends with a
STOP condition defined as a rising edge on SDA with
SCL high. Between the START and STOP conditions,
the device address, the command byte, and the data
bytes are sent. The MAX1645/MAX1645As’ device
address is 0x12 and supports the charger commands
as described in Tables 1–6.
Battery Charger Commands
ChargerSpecInfo()
The ChargerSpecInfo() command uses the Read-Word
protocol (Figure 3b). The command code for
ChargerSpecInfo() is 0x11 (0b00010001). Table 1 lists
the functions of the data bits (D0–D15). Bit 0 refers to
the D0 bit in the Read-Word protocol. The
MAX1645/MAX1645A comply with level 2 Smart Battery
Charger Specification Revision 1.0; therefore, the
ChargerSpecInfo() command returns 0x01.
ChargerMode()
The ChargerMode() command uses the Write-Word
protocol (Figure 3a). The command code for
ChargerMode() is 0x12 (0b00010010). Table 2 lists the
functions of the data bits (D0–D15). Bit 0 refers to the
D0 bit in the Write-Word protocol.
To charge a battery that has a thermistor impedance in
the HOT range (i.e., THERMISTOR_HOT = 1 and THER-
MISTOR_UR = 0), the host must use the Charger
Mode() command to clear HOT_STOP after the battery
is inserted. The HOT_STOP bit returns to its default
power-up condition (“1”) whenever the battery is
removed.
ChargerStatus()
The ChargerStatus() command uses the Read-Word
protocol (Figure 3b). The command code for Charger
Status() is 0x13 (0b00010011). Table 3 describes the
functions of the data bits (D0–D15). Bit 0 refers to the
D0 bit in the Read-Word protocol.
The ChargerStatus() command returns information
about thermistor impedance and the MAX1645/
MAX1645A’s internal state. The latched bits, THERMIS-
TOR_HOT and ALARM_INHIBITED, are cleared when-
MAX1645/MAX1645A
Advanced Chemistry-Independent, Level 2
Battery Chargers with Input Current Limiting
Figure 3. SMBus a) Write-Word and b) Read-Word Protocols
ever BATTERY_PRESENT = 0 or ChargerMode() is writ-
ten with POR_RESET = 1. The ALARM_INHIBITED sta-
tus bit can also be cleared by writing a new charging
current OR charging voltage.
MAX1645/MAX1645A
Advanced Chemistry-Independent, Level 2
Battery Chargers with Input Current Limiting
Figure 4. SMBus Serial Interface Timing—Address
Figure 5. SMBus Serial Interface Timing—Acknowledgment
