MAX9937EVKIT+ Maxim Integrated Products, MAX9937EVKIT+ Datasheet - Page 10

• Manufacturer Part Number: MAX9937EVKIT+
• Description: EVAL KIT FOR MAX9937
• Manufacturer: Maxim Integrated Products

Specifications of MAX9937EVKIT+

• Channels Per Ic: 1 - Single
• Amplifier Type: Current Sense
• Output Type: Single-Ended
• -3db Bandwidth: 350kHz
• Current - Output / Channel: 22mA
• Operating Temperature: -40°C ~ 125°C
• Current - Supply (main Ic): 20µA
• Voltage - Supply, Single/dual (±): 2.7 V ~ 5.5 V
• Board Type: Fully Populated
• Utilized Ic / Part: MAX9937
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Slew Rate: -

Automotive Current-Sense Amplifier
with Reverse-Battery Protection
At frequencies below the output corner frequency, the
MAX9937 itself provides excellent 100dB (DC) com-
mon-mode rejection. At higher frequencies, as the
CMRR of the MAX9937 degrades, the output filter
formed by R
mode rejection of the circuit.
Short-duration overvoltages on the battery line are iso-
lated from the RSP and RSN pins of the MAX9937 by
the use of input resistors R
ESD clamp structure is designed so that the device can
withstand short-duration (< 1s) overvoltages up to 40V
when using resistors R
as shown in the Typical Application Circuit .
Approximately 40mA flows out of each ESD diode dur-
ing this condition (20V/500Ω). This current is less than
the 50mA absolute maximum specification for the RSN
and RSP pins.
Due to low temperature drift of input bias current and
input offset voltage in the MAX9937, the part can be
used to provide powerful application and system bene-
fits not normally attainable from other current-sense
amplifiers on the market. For example, input resistors
R
to introduce an external, controlled input offset voltage
into the circuit. Doing so allows microcontroller firmware
to trim out input offset voltages completely by using
production-line calibration during the manufacturing
process or in system operation as long as a zero load-
current condition is forced. Only minimal temperature-
drift-based errors in the resistor and in the bias currents
then remain.
while gain = R
Since gain can be fixed by choosing R
positive offset voltage can be induced by varying the
value of R
For example:
R
choosing R
the additional V
10
ΔV
RSP
OUT
OS
______________________________________________________________________________________
and R
= 10kΩ, R
V
(max) = (5.6µA x 2500) ± (0.12 x 5.6µA x 2500) -
OS-FINAL
RSN
RSN
(5.6µA x 500) = 11.2mV ± 1.7mV
RSN
OUT
OUT
compared to R
OS
= 2.5kΩ, and knowing ΔI
can be intentionally mismatched so as
Input Common-Mode Voltages
RSP
= V
and C
/R
Skewed Input Offset Voltage
becomes:
RSP
OS
= 500Ω fixes gain = 20V/V. Now,
for Production Calibration
RSP
+ I
.
OUT
B-
and R
RSP
helps boost the common-
x R
RSP
RSN
RSN
.
and R
> 28V and < 0V
- I
of 500Ω or greater
OUT
B+
RSN
B
= ±12% of I
x R
and R
. The input
RSP
RSP
, a
B
,
Since the minimum extra V
greater than the maximum V
amplifier (= 1mV), the output of the current-sense
amplifier is always greater than zero even at zero sense
voltage, thus allowing the current-sense amplifier to be
calibrated at zero input current.
The input terminals go into a high-impedance mode
when V
shutdown 1µA specification. Due to the low 20µA sup-
ply current, this then becomes a convenient way to put
the amplifier in shutdown simply by using a digital I/O
port of a microcontroller to power up/down the current-
sense amplifier. This can be especially useful in certain
battery-operated applications that need to implement
flexible power-management schemes.
For the latest package outline information and land patterns, go
to www.maxim-ic.com/packages.
PROCESS: BiCMOS
ΔV
PACKAGE TYPE
OS
5 SC70
(min) = (0.8µA x 2500) ± (0.12 x 0.8µA x 2500) -
CC
Operation with V
TOP VIEW
= 0, as shown by the input bias current in
(0.8µA x 500) = 1.6mV ± 0.24mV
V
GND
OUT
CC
PACKAGE CODE
1
2
3
Package Information
+
MAX9937
X5+1
SC70
OS
Pin Configuration
Chip Information
introduced into the part is
CC
OS
of the current-sense
= 0V (Shutdown)
5 RSP
4
RSN
DOCUMENT NO.
21-0076