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MAX14922
High-Side Switch Controller with Current
Limiting
General Description
Benefits and Features
The MAX14922 is a high-side, n-channel FET controller
for implementing industrial high-side switches for switching ground-connected loads. The MAX14922 device controls an external nMOS power transistor, allowing low RON
high-side switch applications from a +9V to +70V supply
range.
● +9V to +70V Operating Supply Range
● 5V / 50mA Integrated Linear Regulator
● -40°C to +125°C Ambient Temperature Operating
Range
● 16-TQFN Package, 3mm x 3mm, 0.5mm Pin Pitch
● Robust Design Features
• Ultra High-Speed Inductive Load Turn-Off by
Clamping to -70V
• Supply Independent Inductive Clamping
• Support of Low RON FETs Having Qg (Total) =
50nC
• External FET Turn-On Propagation Delay < 20µs
• Active Current Limit Control During Overcurrent
Fast inductive load turn-off can be achieved with use of a
high-voltage TVS diode enabling up to -70V (max) voltage
clamping. Ground-connected TVS diodes allow clamping
of exceptionally high inductive energies.
Load current is limited to a user-defined value through
a sense resistor. External FET overload protection is
achieved using an auto-retry timing feature, as defined by
a user-selected capacitor (CBLANK at tBLANK input) or optionally using an external timing control.
● Fault Monitoring Diagnostic Features
• Overcurrent Detect Output
• High Supply-Voltage Indication
• Flexible Supply or Load Voltage Monitor
• Undervoltage Lockout
• Thermal Warning and Shutdown Protection
• Device Ready Indication
The MAX14922 features an on-chip comparator enabling
monitoring of the high-side switch output or the supply input voltage with a user-selected threshold. An integrated
charge pump enables high speed switching rates when
using low RON FETs in the 20kHz to 50kHz range.
The MAX14922 is available in a 3mm x 3mm, 16-TQFN
package. The MAX14922 device is specified over the
-40ºC to +125ºC operating temperature range.
Ordering Information appears at end of data sheet.
Applications
●
●
●
●
Industrial Digital Outputs
High-Side Switches
Motor Holding Brakes
Relay and Solenoid Drivers
Simple High-Side Switch Application
SYSTEM
POWER (24V)
LOAD
CONNECTOR
RS
CBYPASS
TVS
µC
SNS
IN
MAX14922
FAULT
MONITOR
19-100761; Rev 0; 4/20
G
VDD
GND
LOAD
S
tBLANK
CBLANK
MAX14922
High-Side Switch Controller with Current Limiting
TABLE OF CONTENTS
General Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Benefits and Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Simple High-Side Switch Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Absolute Maximum Ratings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Package Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
16 TQFN. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Electrical Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Typical Operating Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Pin Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
MAX14922 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Pin Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Functional Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Functional Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Detailed Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Logic Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
5V Linear Regulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Inductive Loads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Diagnostic Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Output or Supply Voltage Monitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Output Ready . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
High Supply Indication (OV) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Overcurrent Monitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Current Limiting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Current Limit Auto-Retry Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Short-Circuit Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Thermal Warning and Shutdown . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Maximum Switching Frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Applications Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Selecting the Power nFET Transistor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Transient EMC Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Inductive Clamping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Operation with High Supply Voltages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Typical Application Circuits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
2A / 24V Application Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
2A / 60V Application Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Ordering Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Revision History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
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19-100761
Maxim Integrated | 2
MAX14922
High-Side Switch Controller with Current Limiting
LIST OF FIGURES
Figure 1. IN to G Propagation Times. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Figure 2. High Supply Shut-off Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Figure 3. Transient EMC Protection Scheme . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
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19-100761
Maxim Integrated | 3
MAX14922
High-Side Switch Controller with Current Limiting
Absolute Maximum Ratings
VDD (Continuous) ................................................... -0.3V to +75V
VDD (100μs) ........................................................... -0.3V to +85V
SNS (Continuous) ...........................(VDD - 0.3V) to (VDD + 0.3V)
SNS (100μs).................................................. -0.3V to (VDD + 6V)
S ..................................................................... -70V to (VDD + 6V)
G.......................................... (S - 0.3V) to min(S + 18, CP + 0.3V)
CP.....................................................(VDD - 0.3V) to (VDD + 18V)
VL ............................................................................. -0.3V to +6V
IN, tBLANK, COMP.................................................... -0.3V to +6V
V5, OVCURR, THW, RDY, OV ................................. -0.3V to +6V
LO ................................................................. -0.3V to (VL + 0.3V)
Continuous Power Dissipation (Multilayer Board) (TA = +70°C,
derate 23.10mW/°C above +70°C.) .............................1847.6mW
Operating Temperature Range ...........................-40°C to +125°C
Junction Temperature ....................................................... +150°C
Storage Temperature Range ..............................-40°C to +150°C
Soldering Temperature (reflow) ........................................ +260°C
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 Information
16 TQFN
Package Code
T1633+5C
Outline Number
21-0136
Land Pattern Number
90-0032
THERMAL RESISTANCE, SINGLE-LAYER BOARD
Junction-to-Ambient (θJA)
68°C/W
Junction-to-Case Thermal Resistance (θJC)
10°C/W
THERMAL RESISTANCE, FOUR-LAYER BOARD
Junction-to-Ambient (θJA)
43.3°C/W
Junction-to-Case Thermal Resistance (θJC)
4°C/W
For the latest package outline information and land patterns (footprints), go to www.maximintegrated.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 thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a
four-layer board. For detailed information on package thermal considerations, refer to www.maximintegrated.com/
thermal-tutorial.
Electrical Characteristics
(VDD = +9V to +70V, V5 = 5.0V, VL = 2.5V to 5.5V. TA = -40°C to +125°C. Typical values are at TA = +25ºC, VDD = +24V, and VL = 5V.
Limits over the operating temperature range and relevant supply voltage range are guaranteed by design and characterization.) (Note
1)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
70
V
1.25
mA
9.0
V
VDD Supply
Operating Supply
Voltage
VDD
Range for which the high-side switch
operates normally
Supply Current
IDD
VDD = 24V, IN = X, No Load on V5
Undervoltage-Lockout
Threshold
VDD_UV
Undervoltage-Lockout
Hysteresis
VDD_UVHYST
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VDD rising, UV turns active low and G is
turned low/off when VDD < VDD_UV
9
0.9
7.7
0.5
19-100761
V
Maxim Integrated | 4
MAX14922
High-Side Switch Controller with Current Limiting
Electrical Characteristics (continued)
(VDD = +9V to +70V, V5 = 5.0V, VL = 2.5V to 5.5V. TA = -40°C to +125°C. Typical values are at TA = +25ºC, VDD = +24V, and VL = 5V.
Limits over the operating temperature range and relevant supply voltage range are guaranteed by design and characterization.) (Note
1)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
VDD rising; OV turns on low when VDD >
VDD_OV
36.5
38.5
40.5
V
5.1
V
OVERVOLTAGE DETECTION (OV)
Overvoltage Threshold
Overvoltage-Lockout
Hysteresis
VDD_OV
VDD_OVHYST
1
Linear Regulator (V5)
Linear Regulator Output
Voltage
V5
V5 Short-Circuit Current
Limit
ICL_V5
0mA to 50mA load current on V5 (Note 2)
4.9
5
50
mA
V5 Undervoltage
Lockout Threshold
V5_UVLO
V5 Undervoltage
Lockout Hysteresis
V5_UVLO_HYS
V5 Load regulation
ΔV5_LDR
VDD = 24V, 1mA ≤ ILOAD_V5 ≤ 50mA
(Note 2)
0.4
1
%
V5 Line Regulation
ΔV5_LNR
9V ≤ VDD ≤ 70V, ILOAD_V5 = 1mA
0.1
0.5
mV/V
V5 Load Capacitance
V5 rising
3.8
4.2
0.4
CV5
External capacitance on V5
Logic Supply Current
IVL
IN = X
Logic Supply Input
Voltage
VL
0.8
V
V
1
μF
Logic Supply (VL)
Logic Supply
Undervoltage-Lockout
Threshold
Logic Supply
Undervoltage-Lockout
Threshold Hysteresis
VL_UVLO
10
VL Rising
16
μA
2.5
5.5
V
1.4
2.1
V
VL_UVLO_HYS
100
T
mV
LOGIC I/O (IN, LO, RDY, OVCURR, THW, OV)
Input Voltage High
VIH
Input Voltage Low
VIL
Input Threshold
Hysteresis
Input Pulldown Resistor
VI_TH
RPULLDOWN
0.7 x VL
0.3 x VL
VL = 5.5V
0.35
IN Input
140
Output Logic High
VOH
LO, IOUT = -5mA
Output Logic Low
VOL
IOUT = +5mA
Output Three-State
Leakage
ILEAK
V
200
V
260
VL - 0.2
All logic outputs, GND < V < 5V
-1
VCL = (VSNS – VDD)
27
V
kΩ
V
0.2
V
+1
µA
33
mV
CURRENT SENSE (SNS)
Current Limit Threshold
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VCL
19-100761
30
Maxim Integrated | 5
MAX14922
High-Side Switch Controller with Current Limiting
Electrical Characteristics (continued)
(VDD = +9V to +70V, V5 = 5.0V, VL = 2.5V to 5.5V. TA = -40°C to +125°C. Typical values are at TA = +25ºC, VDD = +24V, and VL = 5V.
Limits over the operating temperature range and relevant supply voltage range are guaranteed by design and characterization.) (Note
1)
PARAMETER
SYMBOL
SNS Input Current
ISNS
Short-Circuit Current
Threshold
SCTH
CONDITIONS
VDD - 300mV ≤ VSNS ≤ VDD + 300mV
MIN
TYP
-1
MAX
UNITS
+1
µA
40
mV
Auto-Retry Current Limiting Timing
Blanking Time Range
tON_CL
Settable through tBLANK capacitor, VDS <
3V
0.2
100
ms
Blanking Time External
Capacitance
CBLANK
External capacitance to obtain a blanking
time between 0.2ms and 100ms
1
500
nF
Blanking Time Accuracy
tON_CL_ACC
tON_CL versus ideal based on 100%
accurate capacitor
-15
+15
%
ON to OFF time while in overcurrent
1.6
2.5
%
VS +
11.9
VS +
14.1
V
Auto-Retry Duty Cycle
2
FET CONTROL (G, S)
Gate-Source OnVoltage
VG_ON
VDD > VDD_UV, IN = HIGH, IG = 1uA
Gate Turn-On Current
IG_SRC
VDD > VDD_UV, IN
= HIGH
During external
FET turn-on
transition
1.5
3.5
mA
Gate Turn-Off Current
IG_SNK
During external FET turn-off transient
1.4
3.4
mA
80
Ω
Gate-Source Resistance
In OFF State
Gate-Source Output
Voltage During Current
Limiting
RGS_OFF
VDD > VDD_UV, IN = LOW
VG_MIN_REG
VDD > VDD_UV, IN = HIGH
Charge Pump Output
Resistance
CPRES
VDD > VDD_UV
Charge Pump Load
Current
CPLOAD
VDD > VDD_UV
IS
0V < VS < 70V
Source Input Current
32
VS + 0.2
V
12
-15
18
kΩ
300
μA
+15
µA
THERMAL PROTECTION
Chip Thermal Shutdown
TCSHDN
Chip Thermal Shutdown
Hysteresis
TCSHDN_HYS
Temperature rising
T
Chip Thermal Warning
TCW
Chip Thermal Warning
Hysteresis
TCW_HYST
Temperature rising
150
°C
10
°C
110
°C
10
°C
PROPAGATION DELAY (IN to G)
Prop Delay Low To High
tPDLH
Delay from IN to VGS rising to VGST =
9V, CGATE = 3.3nF. See Figure 1
11
20
µs
Prop Delay High To Low
tPDHL
Delay between IN switching low to VGS
falling to 4V, CGATE = 3.3nF. See Figure
1
14
20
µs
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19-100761
Maxim Integrated | 6
MAX14922
High-Side Switch Controller with Current Limiting
Electrical Characteristics (continued)
(VDD = +9V to +70V, V5 = 5.0V, VL = 2.5V to 5.5V. TA = -40°C to +125°C. Typical values are at TA = +25ºC, VDD = +24V, and VL = 5V.
Limits over the operating temperature range and relevant supply voltage range are guaranteed by design and characterization.) (Note
1)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
2.8
V
Comparator Input (COMP)
Clamp Voltage
ICOMP = 1mA
Input Threshold High
VTH_COMP
0.99
1.025
1.06
V
Input Threshold Low
VTL_COMP
0.93
0.975
1.01
V
Input Hysteresis
Input Current
VHYST_COMP
IIN_COMP
50
0V < VCOMP < 1.5V
mV
2
uA
Propagation Delay Low
To High
tPLH_COMP
Delay from COMP rising from 0V to 1.5V
to output
0.3
0.66
1.2
μs
Propagation Delay High
To Low
tPHL_COMP
Delay from COMP falling from 1.5V to 0V
to output
0.4
0.67
1.3
μs
DEBOUNCE TIMES
Supply Undervoltage
Debounce Time
tVDD_UV_DB
200
µs
Supply Overvoltage
Debounce Time
tVDD_OV_DB
200
µs
±9
kV
EMC PROTECTION
S to GND, IEC-61000-4-2 Contact
ESD IEC Contact
Discharge
VESD_C
ESD IEC Air Discharge
VESD_A
S to GND, IEC-61000-4-2 (Note 3)
±15
kV
VESD
All other pins. Human Body Model
±2
kV
S to GND, IEC61000-4-5 with 42Ω, TVS
on S (Note 3)
±2
kV
ESD
Surge Tolerance
VSURGE
(Note 3)
Note 1: All units are production tested at TA = +25°C. Specifications over temperature are guaranteed by design.
Note 2: A regulator with higher output load current creates high power dissipation. A 50mA output load current is only feasible by
limiting the ambient temperature (TA) or supply voltage VDD.
Note 3: Surge and ESD tolerances are tested with TVS protections on VDD to GND and on S to GND. The maximum voltages are
limited to ±85V by the TVS limit. A 200V tolerant transistor is connected between SNS, S, and G.
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19-100761
Maxim Integrated | 7
MAX14922
High-Side Switch Controller with Current Limiting
IN
tPD_LH
tPD_HL
VGST
VGS
VGS = 4V
Figure 1. IN to G Propagation Times
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19-100761
Maxim Integrated | 8
MAX14922
High-Side Switch Controller with Current Limiting
Typical Operating Characteristics
(VDD = 24V, VL = 5V, TA = 25°C, unless otherwise noted. )
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19-100761
Maxim Integrated | 9
MAX14922
High-Side Switch Controller with Current Limiting
Typical Operating Characteristics (continued)
(VDD = 24V, VL = 5V, TA = 25°C, unless otherwise noted. )
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19-100761
Maxim Integrated | 10
MAX14922
High-Side Switch Controller with Current Limiting
Typical Operating Characteristics (continued)
(VDD = 24V, VL = 5V, TA = 25°C, unless otherwise noted. )
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19-100761
Maxim Integrated | 11
MAX14922
High-Side Switch Controller with Current Limiting
Pin Configuration
G
tBLANK
OV
THW
MAX14922
12
11
10
9
TOP VIEW
14
VDD
15
CP
16
MAX14922
EP
+
GND
1
2
3
4
LO
SNS
VL
13
V5
S
8
OVCURR
7
COMP
6
IN
5
RDY
TQFN-EP
3mm x 3mm
Pin Description
PIN
NAME
FUNCTION
TYPE
POWER SUPPLY
Ground
Ground/
Supply
Return
V5
Linear Regulator Output, 5V. Connect a 1µF bypass capacitor to GND.
Supply
3
VL
Logic Supply Input. Connect supply between 2.5V and 5.5V to VL. Connect a
100nF bypass capacitor to GND.
Supply
15
VDD
Supply Voltage, Nominally 24V. Bypass VDD to GND using a 10µF capacitor.
Supply
CP
Charge-Pump Tank Capacitor. Connect a 1µF/16V capacitor between CP and
VDD.
Supply
SNS
Sense Input. Connect a current sense resistor between SNS and VDD to define
the maximum load current. Sense is a high-impedance analog voltage input.
HV Input
1
GND
2
16
CURRENT SENSE
14
FET DRIVE
12
G
Gate Drive Output. Connect to G to the gate of the nMOS power FET.
S
Source Input. Connect to Source terminal of the nMOS power FET. This is a highimpedance input. Connect a 1nF capacitor to GND for improved EMC.
HV Input
6
IN
Switch Control Input. Drive IN high to close the HS switch; drive IN low to open the
HS switch.
Logic Input
7
COMP
Comparator Input. Generates the LO output
Analog Input
tBLANK
Blanking Time Input. Connect a capacitor between tBLANK and GND to set the
overcurrent auto-retry blanking time. Connect tBLANK to GND to disable auto-retry
current limiting. See the Detailed Description section for details.
Analog Input
13
HV Output
CONTROL
11
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Maxim Integrated | 12
MAX14922
High-Side Switch Controller with Current Limiting
Pin Description (continued)
PIN
NAME
FUNCTION
TYPE
DIAGNOSTIC OUTPUTS
4
LO
Output Voltage Monitor, Push-Pull. LO is low when the COMP voltage is higher
than the threshold voltage. LO is high when the COMP input voltage is lower than
the threshold voltage.
Logic Output
5
RDY
Ready Open-Drain Logic Output. RDY turns output low when, for any reason, the
output keeps the external FET off. Connect a pullup resistor, if used.
Logic Output
8
OVCURR
Overcurrent Open-Drain Logic Output. OVCURR turns output low when the highside switch is in current limit. If used, connect a pullup resistor to use OVRCURR.
Logic Output
9
THW
Thermal Warning Open-Drain Output. The output is asserted low when the
temperature of the chip is higher than the thermal warning voltage. Connect an
external pullup resistor if used.
Logic Output
10
OV
Overvoltage Open-Drain Logic Output. The OV turns on output low when VDD
voltage rises above the OV threshold of 39V typ. Connect a pullup resistor, if
used.
Logic Output
EP
Exposed Pad. Connect exposed pad to GND.
EXPOSED PAD
—
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19-100761
Ground/
Supply
Return
Maxim Integrated | 13
MAX14922
High-Side Switch Controller with Current Limiting
Functional Diagram
Functional Block Diagram
VL
VDD SNS
V5
CP
GND
MAX14922
+5V
LINEAR
REGULATOR
LOGICSUPPLY
INPUT
CURRENT
SENSE
OV
RDY
OVCURR
THW
LO
CHARGE
PUMP
SUPPLY
MONITOR
CURRENTMONITOR
LOGIC
CURRENTLIMIT
CONTROL
TEMPERATURE
CONTROL
GATE DRIVE
AND
PROTECTION
G
1.0V
INTERNAL BIAS
S
COMP
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tBLANK
IN
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Maxim Integrated | 14
MAX14922
High-Side Switch Controller with Current Limiting
Detailed Description
The MAX14922 is a high-side n-channel FET controller for implementing a high-side switch that operates as an industrial
digital output. The MAX14922 is specified for operation with supplies up to 70V. The controller features accurate, active
current limiting with current defined by the RS sense resistor connected between the VDD and SNS inputs.
The device is used with an external low RON FET, which acts as a load switch to industrial loads. High inductive clamping
voltages can be achieved by connecting an external ground-connected TVS diode to the MAX14922 S input. The device
features diagnostics such as load or supply-voltage monitoring, gate output ready, high voltage-supply indication, current
limiting, current limit auto-retry timing, and overcurrent indication.
The MAX14922 features an internal 5V LDO supply output (V5) capable of delivering up to 50mA of output current.
Logic Interface
The logic interface requires a VL supply in the range of 2.5V to 5.5V. This ensures that the logic levels on all logic I/
O pins are CMOS compliant. If used, connect pullup resistors to the open-drain logic outputs. If not used, connect the
open-drain logic outputs to GND.
5V Linear Regulator
The integrated 5V linear regulator (V5) can supply up to 50mA load current. Note that linear regulators have high
power dissipation when powered from high supply voltage. Calculate the power dissipation in the regulator as
PDIS(W) = (VDD − V5) × IV5. The power dissipation might be excessive for high load currents in combination with high
supply voltage resulting in self heating of the device. Verify that the MAX14922 maximum thermal ratings are not
exceeded at the highest operating temperatures.
When the MAX14922 enters thermal shutdown, the V5 linear regulator is automatically turned off. The regulator turns on
automatically when the chip temperature drops by 10°C (typ).
Inductive Loads
When the load current flowing into an inductive load is abruptly stopped when the external FET is turned off, the
inductance tries to draw current, which results in a high kick-back voltage. This kick-back voltage, seen on the source
of the FET, needs to be limited/clamped to a voltage in the range of the Absolute Maximum Ratings, to protect the
MAX14922 S input from negative voltages.
Due to the S input maximum rating of -70V, a ground-connected TVS diode can be used for inductive energy clamping
and absorption. Using a ground-connected TVS diode provides the additional advantage that the clamping voltage is
independent of the VDD supply input voltage, and provides a means for low-power dissipation for inductive clamping by
providing a fast demagnetization event. Ensure that the TVS diode can dissipate the heat during worst-case inductive
load clamping at the highest ambient operating temperature.
Diagnostic Features
MAX14922 integrated diagnostic features enable monitoring and control of vital parameters in the application. In case
of load faults, damaged FET, short-circuit conditions, and unwanted high ambient temperature, the device features logic
outputs that alert the controller to force an appropriate response to ensure safety and reliability of the application. In
cases when the diagnostic outputs are not required, the outputs can either be left unconnected or connected to ground.
Output or Supply Voltage Monitor
The integrated comparator input COMP allows monitoring of any voltage in the system, for example the VDD supply
voltage or the source voltage of the external FET. The internal comparator, compares the COMP input voltage with a
1V (typ) internal reference. The inverse logic is presented on the LO logic output. Connect a resistive voltage-divider
between the S or VDD input to set the threshold voltage.
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Maxim Integrated | 15
MAX14922
High-Side Switch Controller with Current Limiting
Output Ready
RDY is an open drain output that signals normal device operation when RDY is pulled passively high by a pullup resistor.
The device is not ready for normal operation when the MAX14922 actively drives RDY low, signalling an application
issue, regardless of the IN input logic state.
The following conditions drives RDY low:
1.
2.
3.
4.
Undervoltage of any of the power supplies (VDD, V5, and VL).
When the device is in overcurrent for a time longer than the blanking time, i.e, a FET overload condition.
Thermal shutdown.
Charge pump overload: if the external FET is switched on/off at a high frequency, the voltage generated by the charge
pump drops due to a high load current. In this case the output FET is forced OFF to reduced the charge pump current
load, the external FET is re-enabled when the charge pump voltage is higher than 9V.
High Supply Indication (OV)
When the VDD supply voltage rises beyond the OV threshold (approximately +39V), the OV output goes active low. When
the OV is low, the MAX14922 continues to operate normally as the device operates with VDD supply voltages of up to
70V. OV output can indicate that the supply is higher than the system is designed for. OV output can be used to turn the
FET off by driving IN low. The external nMOS transistor is not turned off, remains ON even when OV is low. An external
control signal or a controller can turn off the FET by forcing IN low during an overvoltage condition, or an external and
gate can be used for high supply shut-off operation.
SYSTEM
POWER (24V)
CBYPASS
VCC
OV
VDD
RS
SNS
MAX14922
µC
GPO
IN
G
tBLANK
S
GND
CBLANK
GND
LOAD
GND
Figure 2. High Supply Shut-off Application
Overcurrent Monitor
The open drain OVCURR output transitions low when the load current exceeds the current limit set by the sense resistor
(RS).
Current Limiting
Connect a sense resistor (RS) between VDD and SNS inputs to set the maximum current allowed in the application. The
VCL
current limit is calculated as ICL = R . Consider the variation of ICL due to the tolerance of VCL and RS. When the
S
load current exceeds the current limit, then the device actively regulates the nFET gate-source voltage to control the load
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Maxim Integrated | 16
MAX14922
High-Side Switch Controller with Current Limiting
current.
Current Limit Auto-Retry Timing
During an overcurrent condition, the MAX14922 actively regulates the current during the blanking time set by the
capacitor value on the tBLANK input. If the load draws overcurrent for a period longer than the blanking time, the device
turns the external FET off for protection purposes. After an Off-delay equal to about 50x the blanking time, the nFET is
automatically turned on again. Auto-retry On/Off cycling continues until the cause for overcurrent is removed by the user.
The OVCURR logic output goes low after the detection of the overcurrent, and remains low until the overcurrent condition
is removed. At the end of the blanking time, the RDY output is also asserted low to indicate that the external nFET is
forced off.
During an overcurrent event, internal control logic monitors and reduces the gate voltage so that the VGS is reduced.
Refer to TOC21 and TOC22 in the Typical Operating Characteristics section for information on overcurrent detection
(blanking time and auto-retry).
The blanking time can be defined by the capacitor between the tBLANK input and GND. Select a capacitor value such
that the blanking time to the OFF-time duty cycle does not exceed the nMOS power transistor safe operating area
(SOA) under worst-case supply voltage, temperature, load current, and output short-circuit conditions. The MAX14922
automatically reduces the blanking time duration, proportionally to the nFET VDS (the higher the VDS, the shorter the
blanking time), according to the following formula:
tON_CL(μs) =
2000 × CBLANK(nF)
(10 + 0.9VDS)
Refer to TOC17 and TOC18 for blanking-time dependence on VDS (V) and CBLANK (nF) capacitance in the Typical
Operating Characteristics section.
Auto-retry cycling can be disabled by shorting tBLANK to GND. In this case, the RDY output does not toggle low. A
controller needs to turn off the nFET and manage the overload condition in order to protect the nFET from damage.
Short-Circuit Protection
A short-circuit applied at the load output would result in a high short-circuit current mainly limited by the FET RON. When
the MAX14922 detects an excessively high transient load current, it turns the FET off for about 5μs and then turns the
FET back on at a controlled rate so that the short-circuit load current is then determined by the sense resistor value.
Refer to TOC23 in the Typical Operating Characteristics section for short-circuit detection and intervention response for
the MAX14922.
Thermal Warning and Shutdown
The MAX14922 features integrated temperature monitoring and a protective shutdown feature. The device integrated
temperature sensor signals thermal warning at 110ºC (typical). During thermal warning the THW logic output goes low
indicating an overtemperature warning event. During a thermal warning event, the device is still in normal operation.
When the temperature cools down by 10ºC, the THW logic output goes back high.
When the device temperature rises above 150ºC, MAX14922 enters shutdown mode. Regardless of the state of the IN
input, the Gate output is turned off forcing the external FET to turn off. The internal LDO generating 5V output is turned
off as well. As the temperature reduces by 10ºC, the device returns to normal operation with the THW output low, and
the V5 regulator output on at 5V.
Maximum Switching Frequency
The maximum switching FET frequency is determined by the time and ability of the internal charge pump to charge and
discharge the external power FET gate capacitance. The charge pump delivers 2.5mA (typ) turn-on and turn-off currents
allowing drive of low RON MOSFETs. FET parts specify their gate charge under a typical ON condition. As reference,
the maximum switching frequency that the MAX14922 can switch the Si7322DN having 13nC (typ) specified total gate
charge is 45kHz. Similarly, the low RON SiR622DP with 27nC (typ) specified total gate charge can be switched with
20kHz. The RDY output can be used to check if the charge pump is able to drive a FET at higher frequencies. Refer
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Maxim Integrated | 17
MAX14922
High-Side Switch Controller with Current Limiting
to TOC19 in the Typical Operating Characteristics section for the maximum switching rate vs. gate capacitance of the
external FET.
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Maxim Integrated | 18
MAX14922
High-Side Switch Controller with Current Limiting
Applications Information
Selecting the Power nFET Transistor
The following lists the criteria for selecting a suitable FET for an application.
● The FET current capability must be higher than the maximum required load current.
● RON should be low enough for power dissipation considerations during maximum load current.
● The external FET drain-source breakdown voltage (VBR) or (VDSS) should be larger than the TVS clamp voltage plus
the max supply VDD.
● The FET thermal package impedance must be low enough to dissipate the worst-case transient power dissipation,
which usually is a short circuit to GND or a negative voltage. Use the FET SOA curves in conjunction with blanking
time as a reference.
● The total gate charge should be less than 40nC.
● The gate-source threshold voltage should be > 0.8V.
● The maximum allowable gate voltage should be greater than 16V.
Examples of 100V FETs with MAX14922 are: Si7322, IPD60N10, PSMN021-100, Si4190, and STD100N10.
Transient EMC Protection
The MAX14922 does not have protection against Surge (IEC 6100-4-5) and high levels of ESD (IEC 61000-4-2). A TVS
diode needs to be connected between the S input and GND to protect against such negative Surge and negative ESD.
The same TVS diode also clamps the inductive energy during load turn-off.
The transient currents caused by positive surge and/or ESD voltages applied to OUT flows through the parasitic nMOS
source-drain body diode and the sense resistor into the VDD supply and/or clamping VDD TVS diode, standard nMOS
power transistors, and sense resistors can tolerate the power dissipated in them during standard industrial-level transient
currents of ±2kV/42Ω surge and ±9kV contact ESD.
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19-100761
Maxim Integrated | 19
MAX14922
High-Side Switch Controller with Current Limiting
OUT
24V
10µF
RS
SMBJ33CA
1µF
CP
VDD
SNS
G
S
V5
COMP
VL
OV
RDY
MAX14922
tBLANK
OVCURR
THW
LO
IN
GND
Figure 3. Transient EMC Protection Scheme
Inductive Clamping
Select a TVS power and size that can safely dissipate the energy in the inductive load during load turn-off and
demagnetization under worst-case conditions. The worst case is the highest temperature operating conditions in the
module enclosure with the highest load current and inductance.
Operation with High Supply Voltages
If the maximum VDD operating supply voltage is expected to be higher than the bipolar TVS working voltage, then a
silicon diode should be put in series with the TVS. This is shown in the 2A / 60V Applications Diagram in the Typical
Application Circuit.
Typical Application Circuits
2A / 24V Application Circuit
The following circuit illustrates a circuit for realizing a 2A high-side switch with 24V nominal, 33V maximum supply
voltage and 33V inductive load clamping voltage. The high-side switch RON is (48mΩ + 12mΩ) = 60mΩ. A Zener diode,
SM30T35CAY, clamps the supply at 48V in case of supply overvoltage or excursions.
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Maxim Integrated | 20
MAX14922
High-Side Switch Controller with Current Limiting
Typical Application Circuits (continued)
PRL1632-R012-F
Si7322DN
OUT
24V
10µF
SM30T35CAY
12mΩ
1µF
SMBJ33CA
CP
VDD
SNS
G
S
V5
RP1:RP4 = 3.3kΩ
COMP
VL
3.3kΩ
RP2
RP1
45.3kΩ
RP4
RP3
OV
RDY
MAX14922
tBLANK
1 nF
OVCURR
THW
LO
IN
GND
2A / 60V Application Circuit
The following circuit illustrates a circuit for realizing a 2A load current, 60V maximum supply high-side switch with 30V
inductive load clamping voltage. The high-side switch RON is (48mΩ + 12mΩ) = 60mΩ. In case of supply overvoltage or
overshoot, the SMCJ60 TVS clamps the energy.
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Maxim Integrated | 21
MAX14922
High-Side Switch Controller with Current Limiting
Typical Application Circuits (continued)
PRL1632-R012-F
Si7322DN
OUT
60V
10µF
12mΩ
VS-2EFH01
SMCJ60
1µF
SMBJ30A
CP
SNS
VDD
G
S
V5
MAX14922
RP1:RP2 = 3.3kΩ
COMP
VL
RP1
45.3kΩ
1kΩ
RP2
RDY
OVCURR
tBLANK
1 nF
GND
IN
Ordering Information
PART NUMBER
TEMP. RANGE
PIN PACKAGE
TOP-MARKING
MAX14922ATE+
-40°C to +125°C
16 TQFN-EP*
APB
MAX14922ATE+T
-40°C to +125°C
16 TQFN-EP*
APB
+Denotes a lead(Pb)-free/RoHS-compliant package.
T = Tape and reel.
*EP = Exposed pad.
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19-100761
Maxim Integrated | 22
MAX14922
High-Side Switch Controller with Current Limiting
Revision History
REVISION
NUMBER
REVISION
DATE
0
2/20
DESCRIPTION
Initial release
PAGES
CHANGED
—
For pricing, delivery, and ordering information, please visit Maxim Integrated’s online storefront at https://www.maximintegrated.com/en/storefront/storefront.html.
Maxim Integrated cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim Integrated product. No circuit patent
licenses are implied. Maxim Integrated 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 and the Maxim Integrated logo are trademarks of Maxim Integrated Products, Inc.
© 2020 Maxim Integrated Products, Inc.
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