MAX9918EVKIT [MAXIM]
Fully Assembled and Tested;
| 型号： | MAX9918EVKIT |
| 厂家： | 
MAXIM INTEGRATED PRODUCTS |
| 描述： | Fully Assembled and Tested |
| 文件： | 总7页 (文件大小：107K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
19-4ꢀꢀ2; Rev ±; 4/±9
MAX9918 Evaluation Kit
Evluates:81/MAX920
General Description
Features
The MAX9918 evaluation kit (EV kit) provides a proven
design to evaluate the MAX9918 wide input range, preci-
sion unidirectional/bidirectional, current-sense amplifier
in an 8-pin SO package. The EV kit features Kelvin con-
nections for force and sense at the amplifier inputs and a
very precise current-sense resistor with a tolerance of
±±.ꢀ5. Various test points are included for additional
evaluation.
♦ Wide -20V to +75V Input Range Independent of
Supply Voltage
♦ Operates Off a Single +5V Supply
♦ Unidirectional or Bidirectional Operation
♦ Lead(Pb)-Free and RoHS Compliant
♦ Proven PCB Layout
The MAX9918 EV kit PCB comes with a MAX9918ASA+
installed. Contact the factory for free samples of the pin-
compatible MAX9919FASA+, MAX9919NASA+, and
MAX992±ASA+ to evaluate these devices.
♦ Fully Assembled and Tested
Ordering Information
PART
TYPE
MAX9918EVKIT+
EV Kit
+Denotes lead(Pb)-free and RoHS compliant.
Component List
DESIGNATION QTY
DESCRIPTION
DESIGNATION QTY
DESCRIPTION
±.1µF ±1±5, 1ꢁV XꢂR ceramic
capacitor (±ꢁ±3)
TDK C1ꢁ±8XꢂR1C1±4K
R2
1
1
ꢀ
1
88.ꢂkΩ ±±.15 resistor (±8±ꢀ)
C1
C2
1
1
±.±ꢀΩ ±±.ꢀ5, ±.ꢀꢃ 4-terminal
current-sense resistor (12±ꢁ)
Ohmite LVK12R±ꢀ±DER
R3
1±µF ±2±5, ꢁ.3V XꢀR ceramic
capacitor (±8±ꢀ)
TDK C2±12XꢀR±J1±ꢁM
TP1–TPꢀ
U1
Red test points
Precision bidirectional current-sense
amplifier (8 SO)
JU1
JU2
1
1
2
1
3-pin header
Maxim MAX9918ASA+
2-pin header
—
—
2
1
Shunts
P1, P2
R1
Binding posts
PCB: MAX9918 Evaluation Kit+
1kΩ ±±.15 resistor (±8±ꢀ)
Component Supplier
SUPPLIER
PHONE
WEBSITE
TDK Corp.
84ꢂ-8±3-ꢁ1±±
www.component.tdk.com
Note: Indicate that you are using the MAX9918 when contacting this component supplier.
________________________________________________________________ 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.
MAX9918 Evaluation Kit
Additional Evaluation
1) Turn off the electronic load, remove the shunt from
JU2, and apply +2.ꢀV on REFIN (TP3). This is for
bidirectional operation.
Quick Start
Required Equipment
•
•
•
•
•
MAX9918 EV kit
+ꢀV, 1±mA DC power supply
+14V, 1A DC power supply
2) DVM1 should read +2.ꢀV for the no-load case. Set
the load to 2ꢀ±mA and observe the output at TP4
with DVM1. The amplified output is added to +2.ꢀV.
Set the load to -2ꢀ±mA by swapping the cables
connected to P1 and P2. The output voltage is sub-
tracted from +2.ꢀV by the same amount.
Electronic load or equivalent resistor load
Two digital voltmeters (DVM1, DVM2)
Procedure
The MAX9918 EV kit is fully assembled and tested.
Follow the steps below to verify board operation:
Detailed Description of Hardware
The MAX9918 EV kit provides a proven layout for the
MAX9918 current-sense amplifier. The MAX9918 mea-
sures the load current and provides an analog output
1) Verify that the jumpers are in their default position,
as shown in Table 1.
voltage. The full-scale V
on the MAX9918 is
SENSE
2) Connect the positive terminal of the +ꢀV supply to
VCC and the negative terminal to GND.
ꢀ±mV, allowing for 1A max load with a ꢀ±mΩ current-
sense resistor. Higher load currents can be accommo-
dated by adding a current-sense resistor in parallel with
R3. Exposed copper is available for adding another
current-sense resistor and vias are also available for a
through-hole resistor. RS+ (TP4) and RS- (TPꢀ) are
Kelvin connected.
3) Connect the positive terminal of the +14V supply to
P1. Connect P2 into the positive terminal of an elec-
tronic load. Connect the negative terminal of the elec-
tronic load to the GND terminal on the +14V supply.
4) Connect the positive terminal of DVM1 to OUT
(TP1) and the negative terminal to the GND pad.
Measuring the Load Current
The MAX9918 EV kit comes with a MAX9918ASA+
installed, which sets the gain externally through resis-
tors R1 and R2. The current-sense resistor is ꢀ±mΩ.
The output voltage is dependent on the sense current,
current-sense resistor, and gain (eq. 1). For the
MAX9918 EV kit, the current-sense resistor is ꢀ±mΩ
and the gain is 89.ꢂ, which is set through resistors R1
and R2 (Table 2).
ꢀ) Connect the positive terminal of DVM2 to RS+ (TP4)
and the negative terminal to RS- (TPꢀ).
ꢁ) Turn on the +ꢀV supply first and then the +14V sup-
ply.
ꢂ) Set the electronic load to 2ꢀ±mA and turn the elec-
tronic load on. Observe the output at TP4 with
DVM1. The output voltage should be approximately
9± times the voltage read on DVM2. Repeat for load
currents of ꢀ±±mA and ꢂꢀ±mA.
V
= I
× R
× A (eq. 1)
OUT
SENSE
SENSE V
Table 1. Jumper Table (JU1, JU2)
where R
is ꢀ±mΩ and A is 89.ꢂ for the MAX9918
V
SENSE
EV kit by default.
SHUNT
JUMPER
DESCRIPTION
POSITION
Bidirectional Operation
/
The MAX9918 EV kit can be configured for bidirectional
operation by removing the shunt on JU2 and applying
VCC/2 on REFIN (TP3). That sets the bias voltage to
VCC/2 for a no-current condition. Current in the positive
direction in reference to RS+ and RS- increases the out-
put voltage from VCC/2 and current in the negative direc-
tion decreases the output voltage from VCC/2 (eq. 2).
1-2
Connects SHDN to VCC (shutdown)
JU1
Connects SHDN to GND
(normal operation)
2-3*
REFIN is unconnected and can be
connected externally to VCC/2 for
bidirectional operation
Open
JU2
Connects REFIN to GND; used for
unidirectional operation
Closed*
VCC
2
V
= I
(
× R
× A
+
(eq. 2)
)
OUT
SENSE
SENSE
V
*Default position.
2
_______________________________________________________________________________________
MAX9918 Evaluation Kit
Evluates:81/MAX9206
Evaluating the MAX9919 and MAX9920
Both versions of the MAX9919 have fixed gains and do
not require gain-setting feedback resistors. Remove R1
and R2 to evaluate the MAX9919.
Table 2. Gain (A ) Table
V
PART
GAIN (A )
V
⎛
⎝
⎞
⎟
R2
R1⎠
1+
MAX9918
⎜
The MAX992±’s gain is shown in Table 2. For the same
R1 and R2 values, the MAX992± has a lower gain,
which allows a wider input range for a given current-
sense resistor.
MAX9919F
MAX9919N
4ꢀ
9±
⎛
⎜
⎜
⎞
⎟
⎟
⎛
⎝
⎞
⎟
R2
R1⎠
4
1+
⎜
MAX992±
⎜
⎜
⎝
⎟
⎟
⎠
_______________________________________________________________________________________
3
MAX9918 Evaluation Kit
Evluates:81/MAX920
Figure 1. MAX9918 EV Kit Schematic
4
_______________________________________________________________________________________
MAX9918 Evaluation Kit
Evluates:81/MAX9206
Figure 2. MAX9918 EV Kit Component Placement Guide—Component Side
_______________________________________________________________________________________
5
MAX9918 Evaluation Kit
Figure 3. MAX9918 EV Kit PCB Layout—Component Side
Evluates:81/MAX920
6
_______________________________________________________________________________________
MAX9918 Evaluation Kit
Evluates:81/MAX920
Figure 4. MAX9918 EV Kit PCB Layout—Solder Side
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 _____________________ 7
© 2±±9 Maxim Integrated Products
Maxim is a registered trademark of Maxim Integrated Products, Inc.
SPRINGER
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