MAX8903AEVKIT+ [MAXIM]
Instant OnâWorks with No Battery or Low Battery;
| 型号： | MAX8903AEVKIT+ |
| 厂家： | 
MAXIM INTEGRATED PRODUCTS |
| 描述： | Instant OnâWorks with No Battery or Low Battery 电池 |
| 文件： | 总13页 (文件大小：343K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
19-4413; Rev 2; 10/10
MAX8903A Evaluation Kit
vluates:–E/MAX8903Y
General Description
Features
The MAX8903A evaluation kit (EV kit) is a fully assem-
bled and tested circuit board for evaluating the 2A, 1-cell
Li+ DC-DC battery charger. The EV kit charges a sin-
gle-cell lithium-ion (Li+) battery from a DC input (AC
adaptor) or a USB 100mA/500mA source and provides
system power from the DC input, USB input, or battery.
Battery charge current and SYS current limit are inde-
pendently set. Charge current and DC converter output
current limit can be set up to 2A, respectively. The USB
input current can be set to 100mA or 500mA and USB
suspend mode is also supported. Power not used by
the system is available to charge the battery.
♦ DC-DC Converter Output Current-Limit
Adjustment Range of 0.5A to 2A (EV Kit Standard
Configuration: 2A)
♦ Battery Charger Current-Limit Adjustment Range
of 0.5A to 2A (EV Kit Standard Configuration: 1A)
♦ USB Current Limit of 100mA or 500mA
♦ Efficient 4MHz Switching DC-DC Converter
Powers System Load and Charger
♦ Instant On—Works with No Battery or Low
Battery
The EV kit comes standard with the MAX8903A
installed. However, the EV kit can also be used to evalu-
ate the MAX8903B–MAX8903E and MAX8903Y by
replacing the MAX8903A (U1) with the preferred IC.
♦ 28-Pin, 4mm x 4mm Thin QFN Package with
Exposed Pad
♦ Fully Assembled and Tested
Ordering Information
PART
TYPE
MAX8903AEVKIT+
EV Kit
+Denotes lead(Pb)-free and RoHS compliant
Component List
DESIGNATION QTY
DESCRIPTION
2.2μF 10%, 16V X5R ceramic
capacitor (0805)
TDK C2012X7R1C225K or
equivalent
C1
C2
1
1
2
2
1
4.7μF 10%, 25V X5R ceramic
capacitor (0805)
Murata GRM21BR61E475KA12L or
equivalent
10μF 10%, 10V X5R ceramic
capacitors (0805)
Taiyo Yuden LMK212BJ106KG or
equivalent
C3A, C4
C5, C7
C6
0.1μF 10%, 10V X7R ceramic
capacitors (0402)
TDK C1005X5R1A104K or
equivalent
2.2μF 10%, 6.3V X5R ceramic
capacitor (0603)
Taiyo Yuden LMK107BJ225MA or
equivalent
Figure 1. MAX8903A EV Kit Photo
________________________________________________________________ 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.
MAX8903A Evaluation Kit
Component List (continued)
DESIGNATION QTY
DESCRIPTION
DESIGNATION QTY
DESCRIPTION
C8, C9, C11
0
Not installed, capacitors (0402)
1μH, 2.8A, 54mΩ inductor
(4.1mm x 4.1mm x 1.2mm)
TOKO A1101AS-1R0 (DEA4012CK
series)
4.7μF 10%, 16V X5R ceramic
capacitor (0805)
Taiyo Yuden EMK212BJ475K or
equivalent
L1
1
C10
1
100kΩ NTC thermistor (0402)
Murata NCP15WF104J03RC
NTC
0
Small green LEDs
Panasonic LNJ308G8PRA
D1, D3, D4
D2
3
1
2
1
R1–R4
R5
4
1
2.2kΩ 5% resistors (0402)
100kΩ 1% resistor (0402)
Small red LED
Panasonic LNJ208R8ARA
R6, R10, R14,
R17, R18
0
Not installed, resistors (0402)
USB type-AB right-angle mini jacks
Molex 56579-0576
J1, J2
J3
R7, R8
R9
2
1
2
1
3.01kΩ 1% resistors (0402)
6.04kΩ 1% resistor (0402)
604Ω 1% resistors (0402)
1.21kΩ 1% resistor (0402)
2.1mm male power connector
CUI Inc. PJ-002A-SMT
R11, R12
R13
1.25mm (0.049in) surface-mount,
right-angle pitch header, lead-free,
10 circuits
0.56Ω 1% resistor (0603)
Panasonic ERJ-3RQJR56V
J4
1
R15
U1
—
1
1
Molex 53261-1071
1-cell Li+ charger (28 TQFN-EP*)
Maxim MAX8903AETI+
3-pin headers
Sullins PEC36SAAN
Digi-Key S1012E-36-ND
JU1, JU2, JU3,
JU8, JU9
5
6
Shunts (see Table 1)
Digi-Key S900-ND or equivalent
10
1
2-pin headers
Sullins PEC36SAAN
Digi-Key S1012E-36-ND
JU4–JU7,
JU10, JU11
—
PCB: MAX8903A EVALUATION KIT+
*EP = Exposed pad.
Component Suppliers
SUPPLIER
PHONE
WEBSITE
CUI Inc.
503-612-2300
800-344-4539
800-768-6539
770-436-1300
800-344-2112
760-744-0125
800-348-2496
847-803-6100
847-297-0070
www.cui.com
Digi-Key Corp.
Molex
www.digikey.com
www.molex.com
Murata Electronics North America, Inc.
Panasonic Corp.
www.murata-northamerica.com
www.panasonic.com
www.sullinselectronics.com
www.t-yuden.com
Sullins Electronics Corp.
Taiyo Yuden
TDK Corp.
www.component.tdk.com
www.tokoam.com
vluates:–E/MAX8903Y
TOKO America, Inc.
Note: Indicate that you are using the MAX8903 when contacting these component suppliers.
2
_______________________________________________________________________________________
MAX8903A Evaluation Kit
vluates:–E/MAX8903Y
7) Remove the shunt from pins 1-2 of jumper JU8 and
Quick Start
Recommended Equipment
place the shunt on pins 2-3 of jumper JU8.
8) If 3V ≤ V
≤ 4.1V for MAX8903A/MAX8903B/
BAT
• MAX8903A EV kit
MAX8903C, or 3V ≤ V
≤ 4.0V for MAX8903D/
BAT
• Adjustable DC power supply capable of greater than
6V at 3A
MAX8903E/MAX8903Y, verify that the current
from BATT into the battery is approximately 1A.
• Battery or simulated battery
9) Increase the load current on SYS to 1A.
1-cell Li+ or Li-poly battery (Figure 2A)
10) Verify that the voltage on SYS remains approximate-
ly equal to V
.
BATT
Simulated battery—preloaded power supply
(Figure 2B)
11) Verify that the charge current into the battery
remains near 1A.
• Two digital multimeters (DMM)
• Up to 3A adjustable load
• Three 10A ammeters
12) Increase the load current on SYS to 1.5A.
13) Verify that the voltage on SYS remains approximate-
ly equal to V
.
BATT
Procedure
The EV kit is fully assembled and tested. Follow the
steps below to verify board operation. Use twisted
wires of appropriate gauge that are as short as possi-
ble to connect the battery and power sources.
14) Verify that the charge current into the battery
decreased to approximately 0.5A.
15) Increase the load current on SYS to 2.5A.
16) Verify that current out of the battery (from the bat-
tery to SYS) is near 0.5A.
1) Preset the DC power supply to 6V. Turn off the
power supply. Caution: Do not turn on the power
supply until all connections are completed.
Detailed Description of Hardware
Adjusting the EV Kit for In-Circuit
Evaluation
2) Preset the adjustable load to 0A.
3) Connect the EV kit to the power supply, battery or
preloaded power supply, adjustable load, and
meters, as shown in Figure 3.
Verify that the AC adapter source current limit is higher
than the SYS and BAT current requirements. Note that if
SYS current demand exceeds the DC-DC converter
output current limit, then the battery will help supply the
extra current. The DC-DC converter output current limit
can also be adjusted on the MAX8903A EV kit by
replacing R7 or adjusting JU4 and JU5. Verify that the
USB source supplies at least 500mA. Verify the maxi-
mum charge current rating or desired charge current
4) Ensure that the EV kit has the jumper settings
shown in Figure 3 and Table 1.
5) Turn on the power supply.
6) Verify that the voltage at SYS is approximately 4.4V
and that the current from BATT into the battery is 0A.
A. Li+\Li-POLY BATTERY
BAT
B. SIMULATED BATTERY (PRELOADED POWER SUPPLY)
BAT
0 TO 4.2V
≥ 2.5A
2Ω
≥ 10W
MAX8903A EV KIT
MAX8903A EV KIT
GND
GND
Figure 2. Battery Options for Evaluating the MAX8903A EV Kit
_______________________________________________________________________________________
3
MAX8903A Evaluation Kit
JU11
SYS
A
A
SYS
VOLTMETER
ADJUSTABLE
LOAD
MAX8903A
EVALUATION KIT
1
2
3
A
DC
JU1
GND
BAT
POWER
SUPPLY
GND
BAT
BATTERY OR
VOLTMETER
SIMULATED BATTERY
1
2
3
1
2
3
GND
*ALL AMMETERS NEED TO BE SET FOR 10A READINGS. THIS MINIMIZES THE SERIES IMPEDANCE OF THE AMMETER.
Figure 3. Connection Diagram and Default Jumper Connections
Table 1. Jumper Settings (JU1–JU11)
DESCRIPTION
DEFAULT
POSITION
JUMPER
JU1
LABEL
—
PINS 1-2
PINS 2-3
Pins 2-3 shunted
Use the DC pad or J2 as the DC input
Use the DC pad or J3 as the DC input
Configures DC input as adapter source
(see Table 2)
Configures DC input for USB power
(see Table 2)
JU2
DCM
Pins 1-2 shunted
With DCM pins 1-2 shunted, IUSB sets
500mA USB charge current
With DCM pins 2-3 shunted, IUSB sets
100mA USB charge current
JU3
IUSB
Pins 1-2 shunted
JU4
JU5
JU6
JU7
—
—
—
—
Shunted
Shunted
Open
Shorts out R8 (see Table 3)
Shorts out R9 (see Table 3)
Shunting JU6 shorts out R12 (see Table 4)
Shorts out R13 (see Table 4)
Shunted
Disables the battery charger
(when the charger is off, SYS remains on)
Enables the battery charger
(when the charger is on, SYS remains on)
JU8
CEN
Pins 1-2 shunted
JU9
JU10
JU11
USUS
THM
—
Pins 2-3
Shunted
Shunted
USB suspend mode
USB not suspended
Connects THM to GND to bypass thermistor function
Indicator LED anodes connected to SYS
vluates:–E/MAX8903Y
4
_______________________________________________________________________________________
MAX8903A Evaluation Kit
vluates:–E/MAX8903Y
rating of the battery. Ensure that the charge current set-
ting of the EV kit does not exceed the battery rating, or
replace resistor R11 (or adjust JU6 and JU7) as
required. See the Adjusting the DC-DC Converter
Output Current Limit and BAT Fast-Charge Current
Limit section for more details.
3) When charging the battery with V
> V
,
SYSMIN
BAT
the SYS voltage is regulated at the battery voltage
for lowest power dissipation.
When the input current limit is reached, the first action
taken by the MAX8903 is to reduce battery charge cur-
rent. This allows the charging current to be pro-
grammed for the fastest charge time, without dropping
the SYS load at load currents that would cause the
input supply regulation current to be exceeded.
Adjusting the DC-DC Converter Output
Current Limit and BAT Fast-Charge
Current Limit
If, after the charge current is reduced to 0mA, the load
at SYS still exceeds the input current limit, the battery
helps supply power to support the system load.
Input and charger current limits are set, as shown in
Table 2. It is often preferable to change the input cur-
rent limit as the input power source is changed. The
MAX8903A facilitates this by allowing different input
current limits for the DC and USB inputs.
The MAX8903 features flexible input connections (at the
DC and USB inputs) and current-limit settings (set by
DCM and IUSB) to accommodate nearly any input power
configuration. However, it is expected that most systems
use one of two external power schemes: separate con-
nections for USB and an AC adapter, or a single connec-
tor that accepts either USB or the AC adapter output.
Input and charger current limits are shown in Table 2.
The SYS voltage regulates to three different regulation
points depending on the state of the MAX8903:
1) If CEN is high to disable the charger, or charging is
done, the SYS voltage regulates to 4.4V.
2) When charging the battery with V
< V
, the
BAT
SYSMIN
SYS voltage regulates to V
+ 0.2V and stays
SYSMIN
above V
during transient loads.
SYSMIN
Table 2. Input Limiter Control Logic
DC STEP-DOWN
OUTPUT
CURRENT LIMIT
MAXIMUM
CHARGE
CURRENT***
USB INPUT
CURRENT LIMIT
POWER SOURCE
DOK
UOK
DCM
IUSB USUS
Lesser of
AC Adapter at DC Input
L
L
X
H
L
X
L
X
L
6000/R
1200/R
and
ISET
IDC
6000/R
IDC
Lesser of
USB input off. DC 1200/R and
X
100mA
ISET
input has priority.
100mA
USB Power at DC Input
Lesser of
L
L
X
X
L
L
L
X
H
X
L
L
H
L
500mA
1200/R
and
ISET
500mA
USB suspend
0
Lesser of
1200/R
H
100mA
500mA
and
ISET
100mA
USB Power at USB Input,
DC Unconnected
Lesser of
1200/R
No DC input
H
L
X
H
L
and
ISET
500mA
H
H
L
X
X
X
X
H
X
USB suspend
No USB input
0
0
DC and USB Unconnected
H
***Charge current cannot exceed the input current limit. Charge may be less than the maximum charge current if the total SYS load
exceeds the input current limit.
X = Don’t care.
_______________________________________________________________________________________
5
MAX8903A Evaluation Kit
EV Kit On-Board Current-Limit Adjustment
The MAX8903’s DC-DC converter output current limit
can be adjusted on the EV kit by shunting JU4, JU5, or
both. See Table 3 for jumper and resistor combinations
and corresponding current limits. The BAT fast-charge
current limit can be adjusted by shunting JU6, JU7, or
both. See Table 4 for jumper and resistor combinations
and corresponding fast-charge current limits.
While in fast-charge mode, a large system load or device
self-heating could cause the MAX8903 to reduce charge
current. Under these circumstances, the fast-charge
timer is slowed by 2x if the charge current drops below
50% of the programmed fast-charge level, and suspend-
ed if the charge current drops below 20% of the pro-
grammed level. The fast-charge timer is not affected at
any current if the charger is regulating the BAT voltage at
4.2V (i.e., the charger is in voltage mode).
Thermistor (THM)
The EV kit comes with a thermistor preinstalled on the
NTC footprint. To evaluate the MAX8903A with a bat-
tery-pack thermistor, remove the thermistor and connect
to the EV kit using the THM pad. Details of thermistors
are covered in the MAX8903 IC data sheet. To disable
the thermistor function, shunt jumper JU10.
Indicator LEDs
Indicator LEDs are provided for CHG, FLT, DOK, and
UOK. The CHG LED (D3) is on when the battery charg-
er is in its prequalification and fast-charge states. The
FLT LED (D2) is on when the battery charger has
entered a fault state after the charge timer expires. The
DOK LED (D1) is on when 4.15V < V
< 16V. The
DC
Charge Timers
A fault timer prevents the battery from charging indefi-
nitely. The fault prequalification and fast-charge timers
are controlled by the capacitance at CT (C5).
UOK LED (D4) is on when the source at USB is 4.1V <
V
< 6.6V. Refer to the MAX8903 IC data sheet for
USB
more details regarding CHG, FLT, DOK, and UOK.
Charge Enable (CEN)
When CEN is low, the charger is on. When CEN is high,
the charger turns off. CEN does not affect the SYS out-
put, which remains on. In many systems, there is no
need for the system controller (typically a microproces-
sor) to disable the charger, because the MAX8903
Smart Power Selector™ circuitry independently man-
ages charging and adapter/battery power hand-off. In
these situations, CEN may be connected to ground.
C5
0.15μF
t
= 33min ×
PREQUAL
(t
is when V
< 3V).
PREQUAL
BATT
C5
0.15μF
t
= 660min ×
FST-CHG
t
t
= 15s(MAX8903A/C/ D/Y)
TOP-OFF
TOP-OFF
C
CT
= 132min ×
(MAX8903B/E)
0.15μF
Table 3. DC-DC Converter Output Current Limit (JU4, JU5)
JUMPER
RESISTORS FROM IDC TO
GND
RESISTANCE FROM IDC TO
SYS CURRENT LIMIT (A)
GND (ꢀ)
JU4
JU5
Open
Open
Shunt
Shunt
Open
Shunt
Open
Shunt
R7 + R8 + R9
R7 + R8
R7 + R9
R7
12k
6k
0.5
1
9k
0.66
2
3k
vluates:–E/MAX8903Y
Table 4. BAT Fast-Charge Current Limit (JU6, JU7)
JUMPER
RESISTORS FROM IDC TO
GND
RESISTANCE FROM IDC TO
BAT FAST-CHARGE CURRENT
LIMIT (A)
GND (ꢀ)
JU6
JU7
Open
Open
Shunt
Shunt
Open
Shunt
Open
Shunt
R11 + R12 + R13
R11 + R12
R11 + R13
R11
2.4k
1.2k
1.8k
604
0.5
1
0.66
2
Smart Power Selector is a trademark of Maxim Integrated Products, Inc.
_______________________________________________________________________________________
6
MAX8903A Evaluation Kit
vluates:–E/MAX8903Y
DC
DC
3
4
28
LX
1
1
2
3
DC
DC
JU1
27
LX
2
3
4
5
C10
4.7μF
J2
L1
C1
2.2μF
1μH
R15
0.56Ω
1%
LED
26
25
CS
CS
GND
1
2
PG
PG
JU11
DC
1
3
2
SYS
24
23
SYS
SYS
J3
TP3
1
2
3
C4
10μF
JU2
5
GND
DCM
C7
0.1μF
LX
VL
U1
CHG
6
7
BST
1
2
3
MAX8903A
JU3
R3
2.2kΩ
1%
IUSB
LED
R1
2.2kΩ
LED
22
1%
CHG
D3
8
BATT
GND
DOK
DOK
21
20
D1
J4
BAT
BAT
VL
J4-10
J4-9
J4-8
J4-7
J4-6
J4-5
J4-4
J4-3
J4-2
J4-1
C3A
10μF
9
VL
CT
C5
0.1μF
C6
2.2μF
THM
10
UOK
C8
OPEN
R10
OPEN
TP1
R4
2.2kΩ
1%
LED
R17
OPEN
19
UOK
D4
D2
R7
3.01kΩ
1%
FLT
JU5
JU4
11
12
R2
2.2kΩ
1%
IDC
LED
R9
6.04kΩ
1%
R8
3.01kΩ
GND
18
17
FLT
1%
C9
R14
OPEN
TP2
1
2
3
4
OPEN
USB
GND
R18
OPEN
USB
J1
C2
4.7μF
R11
604Ω
1%
JU7
JU6
VL
13
ISET
R13
1.21kΩ
1%
R12
604Ω
1%
VL
R5
100kΩ
1%
THM
THM
1
2
3
JU8
14
15
16
CEN
THM
VL
R6
OPEN
JU10
C11
OPEN
1
2
3
NTC
JU9
USUS
EP
Figure 4. MAX8903A EV Kit Schematic
_______________________________________________________________________________________
7
MAX8903A Evaluation Kit
vluates:–E/MAX8903Y
Figure 5. MAX8903A EV Kit Component Placement Guide—Top Layer
8
_______________________________________________________________________________________
MAX8903A Evaluation Kit
vluates:–E/MAX8903Y
Figure 6. MAX8903A EV Kit PCB Layout—Top Layer
_______________________________________________________________________________________
9
MAX8903A Evaluation Kit
vluates:–E/MAX8903Y
Figure 7. MAX8903A EV Kit PCB Layout—Inner Layer 2
10 ______________________________________________________________________________________
MAX8903A Evaluation Kit
vluates:–E/MAX8903Y
Figure 8. MAX8903A EV Kit PCB Layout—Inner Layer 3
______________________________________________________________________________________ 11
MAX8903A Evaluation Kit
Figure 9. MAX8903A EV Kit PCB Layout—Bottom Layer
vluates:–E/MAX8903Y
12 ______________________________________________________________________________________
MAX8903A Evaluation Kit
vluates:–E/MAX8903Y
Revision History
REVISION REVISION
PAGES
DESCRIPTION
CHANGED
NUMBER
DATE
0
1
2
1/09
8/09
Initial release
—
Added MAX8903C and MAX8903D to parts evaluated
1–12
1–12
10/10
Added MAX8903B, MAX8903E, and MAX8903Y to parts evaluated
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 ____________________ 13
© 2010 Maxim Integrated Products
Maxim is a registered trademark of Maxim Integrated Products, Inc.
相关型号：
MAX8903DETI+
Power Supply Support Circuit, Adjustable, 1 Channel, BICMOS, 4 X 4 MM, ROHS COMPLIANT, TQFN-28
MAXIM
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