19-5594; Rev 0; 10/10
MAX17085B Evaluation Kit
General Description
The MAX17085B evaluation kit (EV kit) is a complete
and fully assembled and tested PCB that features the
MAX17085B IC, a highly integrated, multichemistry
battery-charger controller with dual step-down convert-
ers and dual LDOs. The EV kit is capable of supplying
power to a system load while simultaneously charging
multichemistry battery packs. During operation, the EV
kit circuit automatically selects the ADAPTER input or the
battery as the main power source for supplying power to
the system load and step-down converters. Whenever
the EV kit circuit current limit is exceeded, the battery-
charge current is reduced automatically, giving priority
to the system load and converters.
The EV kit’s input source-current limit, battery-charge
voltage, maximum battery-charge current threshold,
and output current limit on the step-down converters are
configurable. These thresholds are adjusted by using
on-board circuitry, or by connecting analog signals to
the EV kit. Digital output signals indicate the presence
of a valid ADAPTER and valid step-down converter
voltages. An analog output signal indicates the total
current drawn from either the adapter or the battery.
Input Source Current
S
Monitor Outputs
Features
S
Analog Control Charge Current, Voltage, and
Evaluates: MAX17085B
AC Adapter Current/Battery Discharge Current
AC Adapter Presence
Valid Step-Down Converter Output Voltages
S
5V, Up to 8A Step-Down Converter Outputs
S
3.3V, Up to 8A Step-Down Converter Outputs
S
5V, 3.3V Linear Regulator Outputs
S
Automatic Power-Source Selection
S
Up to 17.5V (4-Cell) Battery Voltage
S
8V to 22V Input Operation
S
4A Input Current Limit
S
System Short-Circuit Protection
S
Cycle-by-Cycle Current Limit
S
Up to 1.4MHz Frequency Operation (Charger)
S
Multichemistry Battery Charger
S
Fully Assembled and Tested
Ordering Information
PART
MAX17085BEVKIT+
TYPE
EV Kit
+Denotes
lead(Pb)-free and RoHS compliant.
Component List
DESIGNATION
ADAPTER,
BATT_IN,
PGND (x5),
SYSLD, VOUT3,
VOUT5
C1
QTY
DESCRIPTION
DESIGNATION
C4, C9
10
Noninsulated banana-jack
connectors
C5, C12, C14,
C22, C27, C28
QTY
0
DESCRIPTION
Not installed, ceramic capacitors
(1206)
0.1uF
Q10%,
50V X7R ceramic
capacitors (0603)
Murata GRM188R71H104K
4.7µF
Q20%,
25V X7R ceramic
capacitors (1206)
Murata GRM31CR71E475M
1.0µF
Q10%,
10V X5R ceramic
capacitors (0603)
Murata GRM188R61A105K
10µF
Q10%,
25V X5R ceramic
capacitors (1206)
Murata GRM31CR61E106K
6
0
Not installed, ceramic capacitor
(0805)
1.0µF
Q10%,
50V X7R ceramic
capacitor (0805)
Murata GRM21BR71H105K
0.01µF
Q10%,
50V X7R ceramic
capacitors (0603)
Murata GRM188R71H103K
C6, C7, C8
3
C2
1
C10, C17, C21,
C29
C13, C19, C23,
C24
4
C3, C11, C25,
C26
4
4
_______________________________________________________________
Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
MAX17085B Evaluation Kit
Evaluates: MAX17085B
Component List (continued)
DESIGNATION
C15, C20
QTY
2
DESCRIPTION
100µF, 6V, 18mI capacitors
(D case)
SANYO 6TPE100MI
4.7µF
Q10%,
6.3V X5R ceramic
capacitors (0603)
Murata GRM188R60J475K
Not installed, ceramic capacitors
(0603)
1000pF
Q20%,
50V X7R ceramic
capacitor (0603)
Murata GRM188R71H102M
3A, 40V Schottky diodes (SMA)
Central Semi CMSH3-40MA
Green LEDs (0603)
200mA, 100V dual diodes
(SOT23)
Fairchild MMBD4148SE
(Top Mark: D4)
350mA, 40V Schottky diode
(SOD123)
Diodes Inc. SD103AW
(Top Mark: S4)
100mA, 80V diode (SOD323)
Diodes Inc. 1N4148WS-7-F
2-pin headers
3-pin headers
2.0µH, 4.5A inductor
Sumida CDR7D28MN-2R0
1.5µH, 11.8A inductors
Sumida CEP125NP-1R5MC
30V, 8.3A n-channel MOSFETs
(8 SO)
International Rectifier
IRF7807D1PBF
30V, 8.5A n-channel MOSFET
(8 SO)
Fairchild FDS8884
30V, 10A n-channel MOSFET
with Schottky (8 SO)
Fairchild FDS6690AS
DESIGNATION
N5, N7
QTY
2
DESCRIPTION
30V, 13A n-channel MOSFETs
(8 SO)
Fairchild FDS6298
30V, 13A n-channel MOSFETs
(8 SO)
Fairchild FDS6670A
60V, 115mA n-channel
MOSFETs (SOT23)
Fairchild 2N7002
30V, 8.8A p-channel MOSFET
(8 SO)
Fairchild FDS4435BZ
249kI
Q1%
resistor (0603)
36.5kI
Q1%
resistor (0603)
0.015I
Q1%,
1W sense resistor
(2010)
IRC LRC-LRF2010LF-01-R015-F
0.01I
Q1%,
1W sense resistor
(2010)
IRC LRC-LRF2010LF-01-R010-F
150kI
Q5%
resistor (0603)
1kI
Q5%
resistors (0603)
0I
Q5%
resistors (0603)
200kI potentiometer
(single turn)
Murata PVG3A204C01R00
Not installed, resistors (0603)
R10, R28, R29, and R30 are
short; R17, R18, and R25 are
open
66.5kI
Q1%
resistors (0603)
82.5kI
Q1%
resistors (0603)
301kI
Q1%
resistor (0603)
47I
Q5%
resistor (0603)
100kI
Q1%
resistors (0603)
4.7I
Q5%
resistors (0603)
21kI
Q1%
resistor (0603)
10kI
Q1%
resistor (0603)
78.7kI
Q1%
resistor (0603)
10I
Q1%
resistors (0603)
C16, C18
2
N6, N8
2
C30, C31
0
N9, N10
2
C32
1
P1
R1
R2
R3
1
1
1
1
D1, D2
D3, D4
2
2
D5, D6
2
R4
R5
R6, R7, R26
R8, R36
R9
1
1
3
2
1
D7
1
D8
JU1, JU2, JU3,
JU6
JU4, JU5
L1
L2, L3
1
4
2
1
2
R10, R17, R18,
R25, R28, R29,
R30
R11, R15
R12, R16
R13
R14
R19, R20, R23,
R32
R21, R22
R24
R27
R31
R33, R34
0
2
2
1
1
4
2
1
1
1
2
N1, N2
2
N3
1
N4
1
2
______________________________________________________________________________________
MAX17085B Evaluation Kit
Evaluates: MAX17085B
Component List (continued)
DESIGNATION
R35
TP1–TP5
U1
QTY
1
5
1
DESCRIPTION
4.99I
Q1%
resistor (0603)
Miniature test points
Integrated battery charger
(40 TQFN-EP*)
Maxim MAX17085BETL+
U2
—
—
*EP
= Exposed pad.
1
6
1
DESIGNATION
QTY
DESCRIPTION
Single OR gate (5 SOT23)
Fairchild NC7S32M5X
(Top Mark: 7S32)
Shunts (JU1–JU6)
PCB: MAX17085B EVALUATION
KIT+
Component Suppliers
SUPPLIER
Central Semiconductor Corp.
Diodes Incorporated
Fairchild Semiconductor
International Rectifier
IRC, Inc.
Murata Electronics North America, Inc.
SANYO Electric Co., Ltd.
Sumida Corp.
PHONE
631-435-1110
805-446-4800
888-522-5372
310-322-3331
361-992-7900
770-436-1300
619-661-6835
847-545-6700
www.diodes.com
www.fairchildsemi.com
www.irf.com
www.irctt.com
www.murata-northamerica.com
www.sanyo.com
www.sumida.com
WEBSITE
www.centralsemi.com
Note:
Indicate you are using the MAX17085B when contacting these component suppliers.
Quick Start
•
•
•
MAX17085B EV kit
Nine voltmeters
5)
6)
7)
Recommended Equipment
Verify that a shunt is installed on only one pin
(forced-PWM mode).
Verify that a shunt is installed across jumper JU6
(relearn disable).
Connect a voltmeter across the following EV kit PCB
pads:
• BATT_IN and PGND
• SYSLD and PGND
• VOUT3 and PGND
• VOUT5 and PGND
• LDO3 and PGND
• LDO5 and PGND
• VAUX and PGND
• IINP and PGND
• PWM and PGND
8V to 22V, 5A variable power supply
The EV kit is a fully assembled and tested surface-mount
board. Follow the steps below to verify board operation.
Caution: Do not turn on the power supply until all
connections are completed.
1)
2)
3)
4)
Verify that a shunt is not installed across jumper JU1
(ISET voltage is set by potentiometer R9).
Verify that a shunt is installed across jumper JU2
(OUT5 enabled).
Verify that a shunt is installed across jumper JU3
(OUT3 enabled).
Verify that a shunt is installed across pins 2-3
of jumper JU4 (BATT voltage set to 13.1V
[3 cell x 4.375V]).
Procedure
8)
9)
Connect the power supply across the ADAPTER
and PGND banana jacks.
Turn on the power supply.
_______________________________________________________________________________________
3
MAX17085B Evaluation Kit
Evaluates: MAX17085B
10) Set the power-supply voltage to 20V.
11) Adjust potentiometer R9 until the PWM voltmeter
measures 425mV. This sets the charge current to 2A.
12) Verify the following :
PARAMETER
BATT_IN
SYSLD
VOUT3
VOUT5
LDO5
LDO3
IINP
MEASURE OUTPUT (V)
13.1
20
3.3
5
5
3.3
0
The EV kit features PCB output pads to access the
5V/100mA and the 3.3V/50mA LDOs integrated in the
IC. The low-current LDOs are available for external use.
The EV kit’s
ACOK
digital output signal indicates the
presence of a valid input source, such as an AC adapter.
The PGOOD digital output signal indicates that the OUT3
and OUT5 converter outputs (3.3V and 5V, respectively)
are within specification. The IINP analog output signal
is a scaled voltage of the total current drawn from the
ADAPTER input or the battery.
The EV kit requires a 5A power source with an 8V to
22V output voltage range connected to the ADAPTER
banana-jack connector, or a power source with an 8V
to 19V output voltage range connected to the BATT_IN
banana-jack connector for normal operation. In a typical
application, the battery pack is connected to BATT_IN
and a DC supply, such as an AC adapter, to the
ADAPTER banana-jack connectors. When the ADAPTER
voltage is higher than 7.2V and the DCIN pin is greater
than V
BATT
+ 500mV, the ADAPTER is selected as the
main power source. The battery at BATT_IN is charged
when the adapter is selected as the main power source
and the system load current is less than the input cur-
rent limit.
The EV kit input source-current limit is set to 4A with
sense resistor R3 (15mI). The input current is the sum
of the system load current, input current to the OUT3 and
OUT5 step-down converters, and battery-charge current
when the ADAPTER input is the main power source,
or is the battery-discharge current when the battery
at BATT_IN is the main power source. When the input
current exceeds the input current limit, the charging
current is reduced to provide priority to the SYSLD load
current. As the SYSLD current approaches the limit
threshold, the charge current drops linearly to zero.
The maximum input source-current limit can be
reconfigured by replacing sense resistor R3. Use the
following equation to select a new sense resistor value:
R3
=
60mV
I
LIMIT
Input Source
13) Verify that green LEDs D3 (ACOK signal) and D4
(PGOOD signal) are on.
14) The EV kit is now ready for additional testing.
Detailed Description of Hardware
The MAX17085B EV kit is a complete and fully
assembled and tested PCB that demonstrates the
highly integrated MAX17085B controller of multichemistry
battery charger, two step-down converters, and two
LDOs. The EV kit circuit is capable of supplying power
to a system load (SYSLD) and two converters connected
to the SYSLD output, while simultaneously charging the
battery pack. The EV kit circuit also integrates a third
step-down, DC-DC converter to implement a precision
constant-current/constant-voltage battery charger.
During operation, the EV kit circuit selects the ADAPTER
or the BATT_IN input as the main power source for
SYSLD. Once the main power source is selected, the
EV kit circuit monitors the input source current. This
input source current is defined as the combined SYSLD
current, OUT3 and OUT5 converter input currents, and
battery-charge current when the ADAPTER input is the
main power source, or as the battery-discharge current
when the battery is the main power source. When the
input source current exceeds the EV kit input current-
limit threshold, the battery-charge current is reduced to
give priority to the system load.
The EV kit features on-board circuitry that allows the
user to adjust and set battery-charge voltage and
maximum battery-charge current. The EV kit also
features a PWM PCB pad that is used to connect an
analog input signal or a PWM signal that configures
maximum battery-charge current up to 3.5A. The BATT
battery-charge voltage threshold can be configured up
to 17.5V by adjusting the voltage at the VCTL and CELLS
input pins.
4
Input Current Limit
where I
LIMIT
is the new maximum input source-current
limit and R3 is the value of the sense resistor.
Refer to the
Setting Input Current Limit
section in the
MAX17085B IC data sheet for further details.
______________________________________________________________________________________
MAX17085B Evaluation Kit
Evaluates: MAX17085B
Battery Charging
Charge Voltage
The EV kit battery-charge voltage can be configured
for up to 17.5V by configuring the per-cell voltage at
the VCTL pin. The EV kit per-cell voltage is configured
to 4.375V by default with shorting resistor R10, which
connects the VCTL pin to REF (2.1V). However, the
per-cell voltage can be set by setting the VCTL voltage
between 0 and 2.1V and multiplying that voltage by
2.083. Cut open the PC trace at resistor R10 and install
resistors R10 and R18 to reset the VCTL pin voltage. Use
the following equations to calculate new resistor values
and configure the per-cell voltage:
V
CELL
=
VCTL
×
2.083
REF
R10
=
−
1
R18
VCTL
where V
CELL
is the per-cell voltage, VCTL is the pin
voltage, REF is 2.1V, and R18 is typically 100kΩ.
The resistor values should not overload the REF linear
regulator. The VCTL voltage must be set between 0
and 2.1V.
Note:
The cell battery-termination voltage is a
function of the battery chemistry and construction.
Consult the battery manufacturer to determine this
voltage.
The total BATT battery-charge voltage can be
calculated with the following equation:
Charge Current
The EV kit maximum battery-charge current can be set
up to 3.5A by using potentiometer R9 to vary the ISET
voltage between 0 and 2.1V. Set the ISET voltage below
26mV, or install a shunt across jumper JU1, to shut down
the charger. See Table 2 for jumper JU1 configuration.
The actual battery-charge current depends on the input
source-current limit and the system load current. When
the system load current exceeds the input source-
current limit, the charging current is reduced to provide
priority to the SYSLD load current. As the SYSLD current
increases to 4A, the charge current drops linearly to zero.
Use the following equation to calculate the required
voltage at the ISET pin to set a new maximum charge
current. The maximum charge current of 3.5A is achieved
when the ISET voltage reaches 740mV:
V
ISET
=
R4
×
REF
×
I
CHG
100mV
where V
ISET
is the voltage at the ISET pin, REF is 2.1V,
I
CHG
is the charge current, and R4 is the value of the
sense resistor (10mI).
The maximum charge current can be reconfigured by
replacing sense resistor R4. Use the following equation
to select a new sense resistor value:
R4
=
100mV
I
CHG
V
BATT
=
N
CELLS
×
VCTL
×
2.083
where V
BATT
is the battery-charge voltage and N
CELLS
is the multiplying cell factor (2, 3, or 4) selected. See
Table 1 to select the multiplying factor and jumper JU4
configuration.
where I
CHG
is the new maximum charge current and R4
is the value of the new sense resistor.
The maximum 3.5A charge current can also be set by
removing the shunt across jumper JU1 and connecting a
PWM input signal to the PWM PCB pad. The PWM signal
should have a 100Hz to 500kHz frequency range and
a duty cycle of 0 to 100%. Refer to the
Setting Charge
Current (ISET)
section in the MAX17085B IC data sheet
for more details.
Table 1. Mode Configuration (JU4)
SHUNT
POSITION
1-2
Open
2-3
CELLS PIN
Connected to
LDO5
Not connected
Connected to
GND
BATT VOLTAGE
SETTING
4 x VCTL x 2.083
2 x VCTL x 2.083
3 x VCTL x 2.083
_______________________________________________________________________________________
5
FPGA/CPLD
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