19-6257; Rev 0; 3/12
EVALUATION KIT AVAILABLE
MAX14626
High-Voltage Reverse-Input-Capable 4–20mA
Current Loop Protector
General Description
Benefits and Features
The MAX14626 current loop protector features a currentlimit switch to prevent damage to the sensor devices due
to faulty current loop conditions. The current-limit switch
features a 25I (typ) on-resistance and operates from a
+2.3V to +36V input voltage range. The accurate current
limit is set to 30mA, making the part ideal for protecting
the sensor reading devices.
S High Performance
Low On-Resistance 25I (typ)
Accurate Q10% Current Limit
+2.3V to +40V Wide Supply Voltage Range
Low Operating Current
Ultra-Low Temperature Coefficient
The MAX14626 handles an overcurrent event in a continuous current-limit mode. Additional safety features
include thermal shutdown to prevent overheating and
reverse-input blocking to protect from being reverse connected into the sensor.
S Robust Protection for Sensors
Avoids Power Dissipation Issues Compared to
Discrete Solutions
Thermal Shutdown
Reverse Input Protection
The device is available in a tiny 6-pin (3mm x 3mm),
TDFN exposed pad package and is specified over the
-40NC to +85NC extended temperature range.
S Saves Space in Compact Systems
Eliminates Need for Discrete PTC Poly Switch,
Zener Diodes, and Resistors
3mm x 3mm, 6-Pin TDFN Package
Applications
Industrial Current Loop Control
Ordering Information appears at end of data sheet.
For related parts and recommended products to use with this part,
refer to www.maxim-ic.com/MAX14626.related.
Typical Operating Circuit
4–20mA CURRENT
SENSOR
(4–20mA)
CURRENT
MAX14626
IN
REF
SUPPLY
OUT
CONTROL AND
PROTECTION
RLOAD
IA
ADC
CURRENT LIMIT
GATE CONTROL
GND
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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.
MAX14626
High-Voltage Reverse-Input-Capable 4–20mA
Current Loop Protector
ABSOLUTE MAXIMUM RATINGS
(All voltages referenced to GND.)
IN to GND ...............................................................-40V to +40V
OUT to GND ......................................................... -0.3V to +40V
Current into IN................................................. Internally Limited
Current into OUT...............................................................100mA
Continuous Power Dissipation (TA = +70NC)
TDFN (derate 23.8mW/NC above +70NC)................1904.8mW
Operating Temperature Range......................... -40NC to +125NC
Maximum Junction Temperature......................................+150NC
Storage Temperature Range............................. -65NC to +150NC
Lead Temperature (soldering, 10s).................................+300NC
Soldering Temperature (reflow).......................................+260NC
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute
maximum rating conditions for extended periods may affect device reliability.
PACKAGE THERMAL CHARACTERISTICS (Note 1)
TDFN
Junction-to-Ambient Thermal Resistance (BJA).............. 42NC/W
Junction-to-Case Thermal Resistance (BJC)..................... 9NC/W
Note 1: Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a fourlayer board. For detailed information on package thermal considerations, refer to www.maxim-ic.com/thermal-tutorial.
DC ELECTRICAL CHARACTERISTICS
(IIN = 50FA to 24mA, TA = -40NC to +85NC, RLOAD = 25I to 1kI, unless otherwise noted. Typical values are at IIN = 10mA, RLOAD
= 250I, and TA = +25NC.) (Note 2)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
2.3
V
36
V
2.8
V
56
FA
65
FA
0.01
0.3
FA
25
45
I
30
33
mA
SUPPLY VOLTAGE
Operating Start Voltage
Operating IN Voltage
VIN_ST
IIN = 20FA
VIN
Operating IN to OUT Drop
Voltage
IIN = 24mA
Quiescent Current (Normal
Mode: 4–20mA)
IQ
RLOAD P 250I
Quiescent Current (CurrentLimit Mode: Current > 25mA)
IQ
IOUT = 30mA, VIN = 5V, RLOAD = 25I
40
Reverse Current
IREV
VIN = -36V, VOUT = 0V, current into OUT
IN to OUT Switch
On-Resistance
RON
VIN = 4V, IOUT = 16mA
Forward Current Limit
ILIM
VIN = 36V
Turn-On Time
tSS
VIN = 3V, time from VIN applied to
VOUT = 90% of VIN (Note 3)
10
Fs
Turn-Off Time
tOFF
Time from thermal shutdown (Note 3)
20
Fs
tLIM
Input current source from 20mA to 50mA
(Note 4)
50
Fs
Input current source from 0mA to 50mA
50
%
2mA P DC IIN P 24mA, DIIN = 1mAP-P at
1kI
> 10
kHz
27
DYNAMIC
Current-Limit Reaction Time
Current-Limit Overshoot Voltage
Input Small Signal Bandwidth
BW
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MAX14626
High-Voltage Reverse-Input-Capable 4–20mA
Current Loop Protector
DC ELECTRICAL CHARACTERISTICS (continued)
(IIN = 50FA to 24mA, TA = -40NC to +85NC, RLOAD = 25I to 1kI, unless otherwise noted. Typical values are at IIN = 10mA, RLOAD
= 250I, and TA = +25NC.) (Note 2)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
THERMAL PROTECTION
Thermal Shutdown
Thermal-Shutdown Hysteresis
+150
NC
20
NC
Note 2: All devices are 100% production tested at TA = +25NC, unless otherwise noted. Limits over the -40NC to +85NC operating
temperature range are guaranteed by design.
Note 3: Turn-on time and turn-off time are defined as the difference in the time between when the output voltage crosses 10% and
90% of the final output voltage.
Note 4: Input current source can support voltage up to +40V (absolute maximum). Current reaction time is defined as the settling
time of the output current after a fault event.
Typical Operating Characteristics
(VIN = 24V, IIN = 10mA, RLOAD = 250I, unless otherwise noted. Typical values are at TA = +25NC.)
QUIESCENT IQ vs. IIN
80
60
50
40
30
70
60
40
30
20
20
10
10
0
0
0
4
8
12
16
20
VIN (V)
24
28
32
36
RL = 250I
50
90
80
QUIESCENT IQ (µA)
70
90
QUIESCENT IQ (µA)
QUIESCENT IQ (µA)
80
QUIESCENT IQ vs. TEMPERATURE
100
MAX14626 toc02
MAX14626 toc01
NO LOAD
90
100
70
60
50
0
5
10
IIN (mA)
15
IIN = 10mA
IIN = 20mA
40
30
20
RL = 100I
MAX14626 toc03
QUIESCENT IQ vs. VIN
100
IIN = 4mA
IIN = 0mA
10
20
0
-40 -25 -10 5
20 35 50 65 80 95 110
TEMPERATURE (°C)
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MAX14626
High-Voltage Reverse-Input-Capable 4–20mA
Current Loop Protector
Typical Operating Characteristics (continued)
(VIN = 24V, IIN = 10mA, RLOAD = 250I, unless otherwise noted. Typical values are at TA = +25NC.)
ON-RESISTANCE vs. TEMPERATURE
ON-RESISTANCE (I)
40
30
VIN = +5V
VIN = +24V
20
VIN = +12V
MAX14626 toc06
MAX14626 toc05
VIN = +2.36V
40
REVERSE CURRENT (nA)
IOUT = 10mA
IIN 0mA TO 20mA
REVERSE CURRENT vs. VOUT
50
MAX14626 toc04
50
VOUT
2V/div
1)
30
20
10
10
0
0
IIN
10mA /div
1) CH1 VOUT 2V 100µs
2)
2) CH4 LIN 100mV 100µs
-40 -25 -10 5
20 35 50 65 80 95 110
0
10
TEMPERATURE (°C)
20
100µs/div
40
30
VOUT (V)
SOFT CURRENT LIMIT:
IIN 15mA TO 35mA
FAULT RESPONSE (SHORT TO WIRE):
IIN 10mA TO 100mA
MAX14626 toc07
MAX14626 toc08
VOUT
1)
5V/div
VOUT
5V/div
1)
IIN
IIN
10mA /div
2)
1) CH1 VOUT 5V 100µs
2) CH4 LIN 100mV 100µs
100µs/div
2)
20mA /div
1) CH1 VOUT 5V 50µs
2) CH4 LIN 100mV 50µs
50µs/div
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MAX14626
High-Voltage Reverse-Input-Capable 4–20mA
Current Loop Protector
GND
I.C.
TOP VIEW
OUT
Pin Configuration
6
5
4
MAX14626
*EP
2
3
I.C.
IN
1
I.C.
+
TQFN
*CONNECT EP TO GND
Pin Description
PIN
NAME
1
IN
Power Input
FUNCTION
2, 3, 4
I.C.
Internally Connected. Connect I.C. to GND.
5
GND
Ground
6
OUT
Switch Output
—
EP
Exposed Pad. Connect EP to GND. Connect to a large ground plane to maximize thermal
performance. Not intended as an electrical connection point.
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MAX14626
High-Voltage Reverse-Input-Capable 4–20mA
Current Loop Protector
Functional Diagram
MAX14626
IN
REF
SUPPLY
OUT
CONTROL AND
PROTECTION
CURRENT LIMIT
GATE CONTROL
GND
Detailed Description
Thermal Shutdown
The MAX14626 current loop protector features a currentlimit switch to prevent damage to the sensor devices due
to faulty current loop conditions. The current-limit switch
features a 25I (typ) on-resistance and operates from a
+2.3V to +36V input voltage range. The accurate current
limit is set to 30mA, making the part ideal for protecting
the sensor reading devices.
The device enters thermal shutdown when the die temperature exceeds +150NC (typ). In thermal shutdown, the
internal FETs are turned off. When the die temperature
drops by 20NC, the device turns back on automatically.
The MAX14626 handles an overcurrent event in a continuous current-limit mode. Additional safety features
include thermal shutdown to prevent overheating and
reverse input blocking to protect from being reverse connected into the sensor.
Reverse Input Protection
The device features reverse input protection to protect
the downstream sensor. When a reverse input voltage is
detected, control circuitry turns off the internal FET and
isolates the output from the input.
Applications Information
Figure 1 shows the device in a 4–20mA current loop sensor
application.
Exposed Pad and Layout Concerns
Connect the exposed pad to a large ground plane to
maximize thermal performance. The exposed pad is not
intended as an electrical connection point.
To optimize the switch response time to output shortcircuit conditions, it is very important to keep all traces
as short as possible to reduce the effect of undesirable
parasitic inductance.
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MAX14626
High-Voltage Reverse-Input-Capable 4–20mA
Current Loop Protector
VOLTAGE SPIKE AND RF SUPRESSION
SENSOR
(4–20mA)
CURRENT
+INPUT
MAX14626
RLOAD = 250I
IA
ADC
IA
ADC
-INPUT
ANALOG INPUT MODULE
+
DC SUPPLY
19.2V TO 32V
CURRENT
LOOP
-
VOLTAGE SPIKE AND RF SUPRESSION
+INPUT
MAX14626
RLOAD = 250I
-INPUT
ANALOG INPUT MODULE
Figure 1. 4–20mA Current Loop Sensor Application
Ordering Information
PART
TEMP
RANGE
PINPACKAGE
TOP
MARK
MAX14626ETT+T
-40NC to
+85NC
6 TDFN-EP*
AVF
+Denotes a lead(Pb)-free/RoHS-compliant package.
T = Tape and reel.
*EP = Exposed pad.
Package Information
For the latest package outline information and land patterns
(footprints), go to www.maxim-ic.com/packages. Note that a
“+”, “#”, or “-” in the package code indicates RoHS status only.
Package drawings may show a different suffix character, but
the drawing pertains to the package regardless of RoHS status.
PACKAGE
TYPE
PACKAGE
CODE
DOCUMENT
NO.
LAND
PATTERN
6 TDFN
T633+2
21-0137
90-0058
Chip Information
PROCESS: BiCMOS
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MAX14626
High-Voltage Reverse-Input-Capable 4–20mA
Current Loop Protector
Revision History
REVISION
NUMBER
REVISION
DATE
0
3/12
DESCRIPTION
Initial release
PAGES
CHANGED
—
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. The parametric values (min and max limits) shown in the Electrical
Characteristics table are guaranteed. Other parametric values quoted in this data sheet are provided for guidance.
Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
©
2012 Maxim Integrated Products
8
Maxim is a registered trademark of Maxim Integrated Products, Inc.