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PDF MAX9928 Data sheet ( Hoja de datos )
| Número de pieza | MAX9928 | |
| Descripción | (MAX9928 / MAX9929) Current-Sense Amplifiers | |
| Fabricantes | Maxim Integrated Products | |
| Logotipo |  |
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Hay una vista previa y un enlace de descarga de MAX9928 (archivo pdf) en la parte inferior de esta página. Total 14 Páginas | ||
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19-4251; Rev 0; 8/08
-0.1V to +28V Input Range, Micropower,
Uni-/Bidirectional, Current-Sense Amplifiers
www.datasheet4u.com
General Description
The MAX9928/MAX9929 low-cost, uni-/bidirectional,
high-side, current-sense amplifiers are ideal for moni-
toring battery charge and discharge currents in note-
books, cell phones, and other portable equipment.
These devices feature a wide -0.1V to +28V input com-
mon-mode voltage range, low 20µA supply current with
VOS less than 0.4mV, and a gain accuracy better than
1.0%. The input common-mode range is independent
of the supply voltage, ensuring that the current-sense
information remains accurate even when the measure-
ment rail is shorted to ground.
The MAX9928F/MAX9928T feature a current output with
transconductance ratios of 5µA/mV and 2µA/mV, respec-
tively. An external resistor converts the output current to a
voltage, allowing adjustable gain so that the input sense
voltage can be matched to the maximum ADC input
swing. The MAX9929F/MAX9929T have a voltage output
and integrate a 10kΩ output resistor for fixed voltage
gains of 50V/V and 20V/V, respectively.
A digital SIGN output indicates direction of current flow,
so the user can utilize the full ADC input range for mea-
suring both charging and discharging currents.
The MAX9928/MAX9929 are fully specified over the -40°C
to +125°C automotive temperature range, and available
in 6-bump UCSP™ (1mm x 1.5mm) and 8-pin µMAX®
packages. The UCSP package is bump-to-bump com-
patible with the MAX4372_EBT.
UCSP is a trademark and µMAX is a registered trademark of
Maxim Integrated Products, Inc.
Pin Configurations and Typical Operating Circuit appear at
end of data sheet.
Features
♦ Wide -0.1V to +28V Common-Mode Range,
Independent of Supply Voltage
♦ 2.5V to 5.5V Operating Supply Voltage
♦ 20µA Quiescent Supply Current
♦ 0.4mV (max) Input Offset Voltage
♦ Gain Accuracy Better than 1% (max)
♦ SIGN Output Indicates Current Polarity
♦ Two IOUT Transconductance Versions Available
2µA/mV (MAX9928T)
5µA/mV (MAX9928F)
♦ Two VOUT Gain Versions Available
20V/V (MAX9929T)
50V/V (MAX9929F)
♦ Pin Compatible with the MAX4372 in UCSP
♦ Available in Ultra-Small 3x2 UCSP
(1mm x 1.5mm) and 8-Pin µMAX Packages
Applications
Monitoring Charge/Discharge Currents in
Portable/Battery-Powered Systems
Notebook Computers
General-System/Board-Level Current Monitoring
Smart-Battery Packs/Chargers
Precision Current Sources
Smart Cell Phones
Super Capacitor Charge/Discharge
Ordering Information
PART
OUTPUT TYPE
GAIN
PIN-PACKAGE
TOP MARK
PKG CODE
MAX9928FAUA+
MAX9928FABT+T †
MAX9928TAUA+
MAX9928TABT+T †
MAX9929FAUA+
MAX9929FABT+T †
Current
Current
Current
Current
Voltage
Voltage
Gm = 5µA/mV
Gm = 5µA/mV
Gm = 2µA/mV
Gm = 2µA/mV
AV = 50V/V
AV = 50V/V
8 µMAX
3x2 UCSP
8 µMAX
3x2 UCSP
8 µMAX
3x2 UCSP
—
+AAA
—
+AAC
—
+AAB
U8-1
R61A1+1
U8-1
R61A1+1
U8-1
R61A1+1
MAX9929TAUA+*
Voltage
AV = 20V/V
8 µMAX
MAX9929TABT+* †
Voltage
AV = 20V/V
3x2 UCSP
Note: All devices are specified over the -40°C to +125°C operating temperature range.
—
+AAD
U8-1
R61A1+1
+Denotes a lead-free/RoHS-compliant package.
*Future product—contact factory for availability.
†The MAX9928_ABT and the MAX9929_ABT use Package Code R61A1+1 with backside coating to minimize die chipping.
________________________________________________________________ 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.
1 page  
-0.1V to +28V Input Range, Micropower,
Uni-/Bidirectional, Current-Sense Amplifiers
w w wEL.ECd TaRItCaALs ChHeARe AtC4TEuRI.ScTICo Sm(continued)
(VRS+ = -0.1V to +28V, VCC = 3.3V, VSENSE = (VRS+ - VRS-) = 0V, ROUT = 10kΩ, for MAX9928_, TA = -40°C to +125°C, unless other-
wise noted. Typical values are at TA = +25°C.) (Note 1)
PARAMETER
SIGN Comparator Propagation
Delay (Low to High)
SIGN Comparator Propagation
Delay (High to Low)
SYMBOL
CONDITIONS
Overdrive = 1mV
tPROP_LH Overdrive = 5mV
Overdrive = 1mV
tPROP_HL Overdrive = 5mV
MIN TYP MAX UNITS
80
µs
30
50
µs
13
Power-Up Time to 1% of Final
Value
VSENSE = 50mV for MAX992_F,
VSENSE = 125mV for MAX992_T,
VRS+ = 3.6V, CLOAD = 10pF
50 µs
Saturation Recovery Time
100mV ≤ VSENSE ≤ 50mV for MAX992_F,
250mV ≤ VSENSE ≤ 125mV for MAX992_T, 4 ms
VRS+ = 3.6V, CLOAD = 10pF
Note 1: All devices are 100% production tested at TA = +25°C. All temperature limits are guaranteed by design.
Note 2: VOS is extrapolated from two point transconductance and gain accuracy tests. Measurements are made at VSENSE =
+5mV and VSENSE = +50mV for MAX992_F and VSENSE = +5mV and VSENSE = +125mV for MAX992_T. These measure-
Note 3:
ments are also used to test the full-scale sense voltage, transconductance, and gain. These VOS specifications are for the
trimmed direction only (VRS+ > VRS-). For current flowing in the opposite direction (VRS- > VRS+), VOS is ±1mV (max) at
+25°C and ±1.8mV (max) over temperature, when VRS+ is at 3.6V. See the Detailed Description for more information.
Guaranteed by common-mode rejection ratio. Extrapolated VOS as described in Note 2 is used to calculate common-mode
rejection ratio.
Note 4: Includes input bias current of SIGN comparator.
Note 5: Leakage in to RS+ or RS- when VCC = 0V. Includes input leakage current of SIGN comparator. This specification does not
add to the bias current.
Note 6: Output voltage should be 650mV below VCC to achieve full accuracy.
Note 7: IOL is the minimum output current in the VSENSE - IOUT transfer characteristics. VOL is the minimum output voltage in the
VSENSE - VOUT transfer characteristic.
Note 8: VSENSE voltage required to switch comparator.
Note 9: Discharge to charge trip point is functionally tested at VCM = -0.1V, +3.6V, and +28V.
Note 10: Guaranteed by PSRR test. Extrapolated VOS as described in Note 2 is used to calculate the power-supply rejection ratio.
VSENSE has to be such that the output voltage is 650mV below VCC to achieve full accuracy.
_______________________________________________________________________________________ 5
5 Page 
-0.1V to +28V Input Range, Micropower,
Uni-/Bidirectional, Current-Sense Amplifiers
www.daOtaUshTeeist4au.choimgh-impedance current source and can drive
an unlimited amount of capacitance.
Voltage Output (MAX9929_)
The output voltage equation for the MAX9929_ is given
below:
VOUT = (RSENSE x ILOAD) x (AV)
where VOUT = the desired full-scale output voltage,
ILOAD = the full-scale current being sensed, RSENSE =
the current-sense resistor, AV = MAX9929F voltage
gain (50V/V) or MAX9929T voltage gain = (20V/V).
SIGN Output
The current/voltage at OUT indicates magnitude. The
SIGN output indicates the current’s direction. The SIGN
comparator compares RS+ to RS-. The sign output is
high when RS+ is greater than RS- indicating positive
current flow. The sign output is low when RS- is greater
than RS+ indicating negative current flow. In battery-
operated systems, this is useful for determining
whether the battery is charging or discharging. The
SIGN output might not correctly indicate the direction of
load current when VSENSE is between -1.8mV to -1.2mV
(see Figure 2). Comparator hysteresis of 0.6mV pre-
vents oscillation of SIGN output. If current direction is
not needed, leave SIGN unconnected.
Applications Information
Choosing RSENSE
The MAX9928_/MAX9929_ operate over a wide variety
of current ranges with different sense resistors. Adjust
the RSENSE value to monitor higher or lower current lev-
els. Select RSENSE using these guidelines:
• Voltage Loss: A high RSENSE value causes the
power-source voltage to drop due to IR loss. For
least voltage loss, use the lowest RSENSE value.
• Accuracy: A high RSENSE value allows lower cur-
rents to be measured more accurately. This is
because offsets become less significant when the
sense voltage is larger.
• Efficiency and Power Dissipation: At high current
levels, the I2R losses in RSENSE might be significant.
Take this into consideration when choosing the resis-
tor value and power dissipation (wattage) rating.
Also, if the sense resistor is allowed to heat up exces-
sively, its value could drift.
• Inductance: If there is a large high-frequency com-
ponent to ISENSE, keep inductance low. Wire-wound
resistors have the highest inductance, while metal
film is somewhat better. Low-inductance metal-film
resistors are available. Instead of being spiral
wrapped around a core, as in metal film or wire-
wound resistors, these are a straight band of metal.
They are made in values under 1Ω.
Use in Systems with Super Capacitors
Since the input common-mode voltage range of the
MAX9928/MAX9929 extends all the way from -0.1V to
28V, they are ideal to use in applications that require
use of super capacitors for temporary or emergency
energy storage systems. Some modern industrial and
automotive systems use multifarad (1F–50F) capacitor
banks to supply enough energy to keep critical sys-
tems alive even if the primary power source is removed
or temporarily disabled. Unlike batteries, these capaci-
tors can discharge all the way down to 0V. The
MAX9928/MAX9929 can continuously help monitor their
health and state of charge/discharge.
UCSP Applications Information
For the latest application details on UCSP construction,
dimensions, tape carrier information, PCB techniques,
bump-pad layout, and recommended reflow tempera-
ture profile, as well as the latest information on reliability
testing results, go to Maxim’s website at www.maxim-
ic.com/ucsp to find Application Note 1891:
Understanding the Basics of the Wafer-Level Chip-
Scale Package (WL-CSP).
PROCESS: BiCMOS
Chip Information
______________________________________________________________________________________ 11
11 Page | ||
| Páginas | Total 14 Páginas | |
| PDF Descargar | [ Datasheet MAX9928.PDF ] | |
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