ONSEMI CAT2300

CAT2300
SENSEFET) Current Monitor
for 0.9 V - 1.5 V Bus
Description
CAT2300 is a controller for SENSEFET® MOSFET current
monitoring in high-side switch applications.
CAT2300 provides current mirroring and ON/OFF control for
SENSEFET MOSFETs. Exact control and matching of the Sense
output of the SENSEFET with the Kelvin voltage insures accurate
current monitoring over a couple of decades of current.
Designed for use with NTMFS4833NST1G, NTMFS4854NST1G
or similar SENSEFET MOSFETs from ON Semiconductor, CAT2300
is the single chip alternative to discrete circuits for monitoring and
controlling 0.9 V − 1.5 V power busses. When teamed with a
SENSEFET, CAT2300 will track currents up to 25 A and resolve
currents below 100 mA.
CAT2300 provides logic level ON/OFF control of the power
MOSFET and its own internal circuitry, reducing power consumption
to virtually zero milliwatts.
Packaged in a space saving low profile 2 x 3 mm TDFN, CAT2300
operates over the full industrial temperature range of −40°C to +85°C.
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TDFN−8
VP2 SUFFIX
CASE 511AK
PIN CONFIGURATION
Sense
1
KS
EN
Kelvin
VDD
Gate
GND
(Top View)
Features
• Precision Current Measurement of 0.9 V − 1.5 V Power Supply Rails
• ON/OFF Power FET Control with Soft−start
• Sense Current Mirroring to 70 mA
•
•
•
•
IMEAS
(equal to 25 A flowing in the power bus)
User Adjustable Current to Voltage Conversion Ratio
150 mV Typical Matching between Kelvin and Sense Leads
Less than 1 mA Current Consumption in Shutdown Mode
This Device is Pb−Free, Halogen Free/BFR Free and RoHS
Compliant
Typical Applications
MARKING DIAGRAM
F3T
LAA
YM
G
F3T
L
AA
Y
M
G
• Portable Computers
• Backplane Bus Control
• Power Distribution
= Specific Device Code
= Assembly Location Code
= Assembly Lot Number
= (Last Two Digits)
= Production Year (Last Digit)
= Production Month (1−9, O, N, D)
= Pb−Free Microdot
ORDERING INFORMATION
Power Bus
Enable
System
Load
SENSEFET
CAT2300
Device
Package
Marking
Shipping†
CAT2300
TDFN
F3T
3,000 / Tape &
Reel
†For information on tape and reel specifications,
including part orientation and tape sizes, please
refer to our Tape and Reel Packaging Specification
Brochure, BRD8011/D.
IMEASURE
Figure 1. System Application
ORDERING INFORMATION
See detailed ordering and shipping information in the package
dimensions section on page 7 of this data sheet.
© Semiconductor Components Industries, LLC, 2012
November, 2012 − Rev. 2
1
Publication Order Number:
CAT2300/D
CAT2300
Gate Kelvin KS
Sense
VREG
1
250 mA
+
VDD
−
0
IMEAS
EN
GND
Figure 2. Simplified Block Diagram
Table 1. PIN FUNCTION DESCRIPTION
Pin No.
Pin Name
1
Sense
2
KS
3
Kelvin
Connects to Kelvin pin of the SENSEFET. Serves as the reference point for Sense lead biasing.
4
Gate
Connects to Gate of the SENSEFET and controls SENSEFET operation.
5
GND
Electrical ground for IC.
6
VDD
External voltage supply for driving the gate of the SENSEFET and power supply for CAT2300 internal
circuitry via an internal voltage regulator.
7
EN
Enable: High true logic input. Turns ON SENSEFET and CAT2300’s internal circuitry. A logic LOW on EN
grounds Gate, shutting off the SENSEFET and shuts down the internal current source and mirroring circuitry.
8
IMEAS
PAD
Function
Connects to Sense pin of SENSEFET and directs sensed current to IMEAS output.
Kelvin Sense; a Kelvin connection for the current mirror control amplifier. This connection must be made
directly to Sense on the SENSEFET package. Do not share any trace length with CAT2300’s Sense lead.
Sensed current output. A resistor between IMEAS and ground develops a voltage proportional to the
current flowing through the SENSEFET.
Backside paddle is internally connected to GND. This pad may be left floating but if connected with PCB it
must be to the ground plane of circuitry which is also grounded.
Table 2. ABSOLUTE MAXIMUM RATINGS (Note 1)
Symbol
Value
Unit
VDD
6.5
V
Gate
±15
mA
VK, EN, Sense, KS, Kelvin, IMEAS
6.5
V
Junction Temperature
150
°C
Parameter
VDD
Stresses exceeding Maximum Ratings may damage the device. Maximum Ratings are stress ratings only. Functional operation above the
Recommended Operating Conditions is not implied. Extended exposure to stresses above the Recommended Operating Conditions may affect
device reliability.
1. Guaranteed by design.
Table 3. RECOMMENDED OPERATING CONDITIONS
Parameter
Symbol
Value
Unit
VK
0.9 to 1.5
V
VDD
5
V
Maximum Junction Temperature
TJUNCTION
125
°C
Ambient Temperature Range
TAMBIENT
−40 to +85
°C
VK
VDD
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2
CAT2300
Table 4. PACKAGE THERMAL PERFORMANCE
Package
Symbol
Test Conditions
qJA
TDFN−8
qJA
Max
Unit
°C/W
35
160
1 oz Copper Thickness, 100 mm2
qJC
Typ
160
1 oz Copper Thickness, 100 mm2
qJC
SOIC−8
Min
°C/W
25
Table 5. DC ELECTRICAL CHARACTERISTICS
(VK = 0.9 – 1.5 V; VDD = +5 V; TAMBIENT = −40°C to +85°C, TJUNCTION = −40°C to +125°C, unless otherwise specified.)
Limits
Parameter
Kelvin voltage
Symbol
Test Conditions
Min
Typ
Max
Units
VK
0.9
1.5
V
Gate Drive input voltage
VDD
4.5
5.5
V
Supply Current on VDD pin
IVDD
1
mA
EN = logic 0
EN = logic 1
Gate drive Sourcing
IGATE
Gate drive Sinking
Offset Voltage
Input Bias Current;
Kelvin and KS inputs
VGATE = VDD – 1 V
VGATE = 0.6 V
VOS
65
77
100
mA
−235
−280
−330
mA
7
9.6
13
mA
±150
±300
mV
100
150
nA
VOS = VKELVIN − VSENSE
VK = 0.9 V to 1.5 V
IK
Power Supply Rejection Ratio
PSRR
IMEAS output current
IMEAS
0
70
70
mA
db
Output voltage of IMEAS amplifier
VO_IM
0
VK – 0.1
V
LOGIC
Low level input voltage
VIL
EN
0.9
1.1
1.26
V
High level input voltage
VIH
EN
1.4
1.65
1.9
V
Low level input current
IIL
EN, VDD = 0 V or 5.5 V
2
mA
High level input current
IIH
EN, VDD = 0 V or 5.5 V
2
mA
Max
Units
Hysteresis
0.55
V
Table 6. AC OPERATING CHARACTERISTICS
(VK = 0.9 V – 1.5 V; VDD = 5 V; TAMBIENT = −40°C to +85°C, TJUNCTION = −40°C to +125°C, unless otherwise specified.)
Limits
Parameter
Symbol
IMEAS output rise time
tR
IMEAS output fall time
tF
IMEAS Settling time
tS
Test Conditions
Min
Typ
20 W, 100 pF, VK = 1.5 V
ISENSE : 2 mA – 70 mA
38
ms
33
ms
EN = Logic 0³1, ISENSE = 1 mA
30
ms
EN = Logic 0³1, ISENSE = 70 mA
50
ms
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3
CAT2300
TYPICAL PERFORMANCE CHARACTERISTICS
IBus
VMEAS
50 ms / div
Figure 3. Load Step: 1 A – 10 A
PIN DESCRIPTION
Sense
Careful layout is critical in achieving full SENSEFET
perfomance. PCB trace resistance can no longer be ignored
as it can be in typical low current circuit designs. Microvolt
offsets (mV) produce meaningful errors in current ratio
tracking. A few milliohms of trace resistance carrying a few
milliamps of current produces microvolts of potential
difference between CAT2300 and the SENSEFET. To
circumvent this error CAT2300 provides a Kelvin lead (KS)
for monitoring the SENSEFET’s Sense pin. Under no
circumstances should the KS connection share any portion
of the current path between the sense pins of CAT2300 and
the SENSEFET. Doing so will degrade measurement
accuracy.
Sense connects directly to the SENSEFET’s Sense pin and
directs the sensed current to the IMEAS output. Sense is
controlled by an amplifier with a FET follower stage to
maintain Sense at exactly the Kelvin voltage, thus insuring
accuracy of the SENSEFET’s mirror current.
KS
KS = Kelvin Sense; a Kelvin connection for the mirroring
amplifier. Current measurement accuracy is dependent upon
the voltage match between the SENSEFET’s Sense and
Kelvin leads. To minimize voltage losses in the PCB trace
between CAT2300 and the SENSEFET, a Kelvin connection
for the control amplifier is provided. KS must be a
dedicated connection, shared by no other circuitry, and
tied directly to the Sense pin on of the SENSEFET.
Kelvin
Kelvin connects directly to the SENSEFET’s Kelvin pin
and acts the reference voltage for CAT2300’s mirroring
circuit. It too must be a dedicated connection, shared by no
other circuitry.
SENSEFET
Gate
Gate connects to the SENSEFET’s Gate pin and controls
the SENSEFET’s operation. Gate is controlled by EN: a
logic 1 turns the SENSEFET ON, a logic 0 turns it OFF.
When ON, voltage is applied to the SENSEFET’s gate via
a current source inside CAT2300.
By controlling the gate drive current a controlled turn-ON
is achieved. Faster turn-on times can be done by adding a
supplemental current source to augment the internal current
source. Placing a resistor between VDD and Gate will
provide extra current and boost turn-on speeds.
For a softer turn-on characteristic, add capacitance
between the SENSEFET’s Gate and Source pins;
approximately 1 nF for every ms of increased delay.
When switching OFF the SENSEFET, Gate provides a
strong pull-down, 7.5 mA typical, so the SENSEFET will be
switched off quickly.
SENSEFET
SENSEFET
Figure 4. Current Sense
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4
CAT2300
VDD
EN
VDD provides gate drive for the SENSEFET and power
for CAT2300’s internal circuitry and must be +5 V.
Enable is a high true logic input controlling the
SENSEFET’s ON/OFF state. A logic high on EN turns the
switch ON; a logic low turns it OFF.
Bus turn-ON time is controlled by the FET’s input gate
capacitance and the drive current applied to the gate.
To minimize power consumption EN disables the internal
gate drive current source and current mirroring circuitry
whenever the SENSEFET is OFF.
IMEAS
IMEAS is the mirror current output. Placing a resistor
between IMEAS and ground produces a voltage proportional
to IBUS. The maximum voltage producible at IMEAS is the
Kelvin voltage (VK) – 0.1 V. This sets a limitation on the
maximum value of RMEAS.
R MEAS +
ǒV K * 0.1 VǓ
I SENSE
+ CSR
ǒV K * 0.1 VǓ
I bus
where:
CSR = Current Sensing Ratio taken from the SENSEFET
data sheet.
Ibus = Max current through the SENSEFET.
NTMF4834NS
VIN
Kelvin
Drain
Source
Sense
Ibus
Gate
Gate
VOUT
ISense
Kelvin KS
Sense
VREG
1
250 mA
+
VDD
−
IMEAS
0
VMEAS
EN
CAT2300
GND
Figure 5. Typical Application
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5
CAT2300
PACKAGE DIMENSIONS
TDFN8, 2x3
CASE 511AK−01
ISSUE A
D
A
e
b
E2
E
PIN#1
IDENTIFICATION
A1
PIN#1 INDEX AREA
D2
TOP VIEW
SYMBOL
MIN
SIDE VIEW
NOM
A
0.70
0.75
0.80
0.00
0.02
0.05
A2
0.45
0.55
0.65
A2
0.20 REF
A3
b
0.20
0.25
0.30
D
1.90
2.00
2.10
D2
1.30
1.40
1.50
E
2.90
3.00
3.10
E2
1.20
1.30
1.40
e
L
BOTTOM VIEW
MAX
A1
A3
FRONT VIEW
0.50 TYP
0.20
0.30
L
0.40
Notes:
(1) All dimensions are in millimeters.
(2) Complies with JEDEC MO-229.
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CAT2300
ORDERING INFORMATION
Part Number
CAT2300VP2−GT3
2.
3.
4.
5.
Temperature Range
Package
Quantity per Reel (Note 5)
Package Marking
−40°C to +85°C
TDFN
3,000
F3T
All packages are RoHS−compliant (Lead−free, Halogen−free).
The standard lead finish is NiPdAu pre−plated (PPF).
For additional package and temperature options, please contact your nearest ON Semiconductor Sales office.
For information on tape and reel specifications, including part orientation and tape sizes, please refer to our Tape and Reel Packaging
Specifications Brochure, BRD8011/D.
SENSEFET is a registered trademark of Semiconductor Components Industries, LLC
ON Semiconductor and
are registered trademarks of Semiconductor Components Industries, LLC (SCILLC). SCILLC owns the rights to a number of patents, trademarks,
copyrights, trade secrets, and other intellectual property. A listing of SCILLC’s product/patent coverage may be accessed at www.onsemi.com/site/pdf/Patent−Marking.pdf. SCILLC
reserves the right to make changes without further notice to any products herein. SCILLC makes no warranty, representation or guarantee regarding the suitability of its products for any
particular purpose, nor does SCILLC assume any liability arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without
limitation special, consequential or incidental damages. “Typical” parameters which may be provided in SCILLC data sheets and/or specifications can and do vary in different applications
and actual performance may vary over time. All operating parameters, including “Typicals” must be validated for each customer application by customer’s technical experts. SCILLC
does not convey any license under its patent rights nor the rights of others. SCILLC products are not designed, intended, or authorized for use as components in systems intended for
surgical implant into the body, or other applications intended to support or sustain life, or for any other application in which the failure of the SCILLC product could create a situation where
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its officers, employees, subsidiaries, affiliates, and distributors harmless against all claims, costs, damages, and expenses, and reasonable attorney fees arising out of, directly or indirectly,
any claim of personal injury or death associated with such unintended or unauthorized use, even if such claim alleges that SCILLC was negligent regarding the design or manufacture
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PUBLICATION ORDERING INFORMATION
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Order Literature: http://www.onsemi.com/orderlit
For additional information, please contact your local
Sales Representative
CAT2300/D