MAXIM MAX14821

19-5916; Rev 1; 2/12
MAX14821
IO-Link Device Transceiver
General Description
Features
The MAX14821 transceiver is suitable for IO-Link®
devices and 24V binary sensors/actuators. All specified
IO-Link data rates are supported. In IO-Link applications, the transceiver acts as the physical layer interface
to a microcontroller running the data-link layer protocol.
Additional 24V digital inputs and outputs are provided.
Two internal linear regulators generate common sensor
and actuator power requirements: 5V and 3.3V.
On-board C/Q and DO drivers are independently configurable for push-pull, high-side (PNP), or low-side (NPN)
operation. The device detects the IO-Link C/Q wake-up
condition and generates a wake-up signal on the activelow WU output. The C/Q and DI inputs have selectable
current loads for use in actuators.
An SPI™ interface allows configuration and monitoring of
the device. Extensive alarm conditions are detected and
communicated through the IRQ output and the SPI interface. The device features reverse-polarity, short-circuit,
and thermal protection. All power lines are monitored for
undervoltage conditions.
The C/Q and DO drivers are specified for sourcing/sinking up to 100mA.
The device is available in a 2.5mm x 2.5mm, 25-pin WLP
and a 4mm x 4mm, 24-pin TQFN package. Both are specified over the extended -40NC to +85NC temperature range.
S IO-Link Specification v.1.0 and v.1.1 Physical LayerCompliant
S Supports COM1, COM2, and COM3 Data Rates
S IO-Link Device Wake-Up Detection
S Push-Pull, High-Side, or Low-Side Outputs
S 100mA Specified C/Q Output Drive
S Auxiliary 24V, 100mA Digital Output
S Auxiliary 24V Digital Input
S Optional 6mA/7mA Current Loads at Both 24V Inputs
S 5V and 3.3V Linear Regulators
S Reverse-Polarity Protected 24V Supply Output
S EMI Emission Control Through Slew-Controlled Driver
S SPI Interface for Configuration and Monitoring
S 2.5V to 5V Logic Interface Levels
S Reverse-Polarity and Short-Circuit Protection on All
24V Inputs/Outputs
S High-Temperature Warning and Thermal Shutdown
S Extensive Fault Monitoring and Reporting
S -40NC to +85NC Operating Temperature Range
S 2.5mm x 2.5mm WLP and 4mm x 4mm TQFN
Packages
Applications
Ordering Information appears at end of data sheet.
IO-Link Sensors Industrial Sensors and Actuators
IO-Link Actuators
Typical Operating Circuit
5V
3.3V
1μF
0.1μF
0.1μF
10kΩ
VCC
GPIO2
UV
VL
TXQ LDO33 V5
LDOIN VP
0.8Ω
VCC
1μF
SPI
IRQ
MICROCONTROLLER
GND
WU
RX
RX
TX
TXC
RTS
TXEN
GPIO1
LO
L+
DO
MAX14821
1
2
C/Q
DI
GND
4
3
L-
IO-Link is a registered trademark of Profibus User Organization (PNO).
SPI is a trademark of Motorola, Inc.
For related parts and recommended products to use with this part, refer to: www.maxim-ic.com/MAX14821.related
�� 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.
MAX14821
IO-Link Device Transceiver
Functional Diagram
LDO33
V5
LDOIN
VP
UV
UV MONITOR
3.3V LDO
5V LDO
VCC
VL
CS
SDI
SDO
SCLK
IRQ
STATUS
AND
CONFIGURATION
RX
FILTER
C/Q
C/Q
LOAD
WAKE-UP
DETECT
WU
PROTECTION
DRIVER
TXQ
TXC
TXEN
LI
PROTECTION
GND
PROTECTION
DI
PROTECTION
DO
DI
LOAD
DRIVER
LO
MAX14821
DoEn
�� Maxim Integrated Products 2
MAX14821
IO-Link Device Transceiver
ABSOLUTE MAXIMUM RATINGS
(All voltages referenced to GND, unless otherwise noted.)
VCC..........................................................................-40V to +40V
VP (IVP < 50mA)...... the higher of -0.3V and (VCC - 1V) to +40V
LDOIN.....................................................................-0.3V to +40V
V5...................... -0.3V to the lesser of (VLDOIN + 0.3V) and +6V
LDO33...................... -0.3V to the lesser of (V5 + 0.3V) and +6V
VL..............................................................................-0.3V to +6V
DI ............................................................................-40V to +40V
C/Q, DO....................... MIN: the higher of -40V and (VCC - 40V)
MAX: the lesser of +40V and (VCC + 40V)
Logic Inputs
TXC, TXQ, TXEN, LO, CS, SDI, SCLK...... -0.3V to (VL + 0.3V)
Logic Outputs
RX, WU, LI, SDO, IRQ.............................. -0.3V to (VL + 0.3V)
UV.........................................................................-0.3V to +6V
Continuous Current Into Any Logic Pin............................ Q50mA
Continuous Power Dissipation
TQFN (derate 27.8mW/NC above +70NC)..................2222mW
WLP (derate 22.7mW/NC above +70NC)....................1816mW
Operating Temperature Range........................... -40NC to +85NC
Maximum Junction Temperature......................................+150NC
Storage Temperature Range............................. -65NC to +150NC
Lead Temperature (TQFN only; 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)
TQFN
Junction-to-Ambient Thermal Resistance (BJA)...........36NC/W
Junction-to-Case Thermal Resistance (BJC)..................3NC/W
WLP
Junction-to-Ambient Thermal Resistance (BJA)...........44NC/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
(VCC = 18V to 36V, VL = 2.3V to 5.5V, VGND = 0V; all logic inputs at VL or GND; TA = -40NC to +85NC, unless otherwise noted. Typical
values are at VCC = 24V, VL = 3.3V, and TA = +25NC, unless otherwise noted.) (Note 2)
PARAMETER
SYMBOL
CONDITIONS
VCC Supply Voltage
VCC
For driver operation
VCC Supply Current
ICC
VCC = 24V, C/Q as input, no load on V5
or LDO33, LDOIN not connected to VP,
VLDOIN = 24V
VCC Undervoltage-Lockout
Threshold
VCCUVLO
VCC Undervoltage-Lockout
Threshold Hysteresis
VCCUVLO_HYST
V5 Supply Current
I5_IN
V5 Undervoltage-Lockout
Threshold
V5UVLO
VL Logic-Level Supply Voltage
VL
VL Logic-Level Supply Current
IL
VL Undervoltage Threshold
VLUVLO
VCC falling
MIN
TYP
MAX
UNITS
36
V
1
2.5
mA
7.4
9
V
9
6
LDOIN shorted to V5, external 5V applied
to V5, no switching, LDO33 disabled
V5 falling
200
mV
3
mA
2.0
V
2.3
All logic inputs at VL or GND
VL falling
0.65
0.95
5.5
V
5
FA
1.30
V
36
V
5
mA
5V LDO (V5)
LDOIN Input Voltage Range
VLDOIN
LDOIN Supply Current
ILDOIN
7
VLDOIN = 24V, C/Q is configured as an
input, no load on V5 or LDO33
2.5
�� Maxim Integrated Products 3
MAX14821
IO-Link Device Transceiver
DC ELECTRICAL CHARACTERISTICS (continued)
(VCC = 18V to 36V, VL = 2.3V to 5.5V, VGND = 0V; all logic inputs at VL or GND; TA = -40NC to +85NC, unless otherwise noted. Typical
values are at VCC = 24V, VL = 3.3V, and TA = +25NC, unless otherwise noted.) (Note 2)
PARAMETER
V5 Output Voltage Range
SYMBOL
V5
V5 Load Regulation
CONDITIONS
No load on V5, 7V P VLDOIN P 36V
1mA < ILOAD < 10mA, VLDOIN = 7V,
0.1FF bypass capacitor on V5
MIN
TYP
MAX
UNITS
4.75
5.00
5.25
V
0.8
%
1mA < ILOAD < 30mA, VLDOIN = 7V,
0.1FF bypass capacitor on V5, 10W–1FF
compensation network added to V5
0.8
3.3V LDO (LDO33)
LDO33 Output Voltage
LDO33 Undervoltage-Lockout
Threshold
VLDO33
VLDO33UVLO
LDO33 Load Regulation
No load on LDO33
3.1
3.3
3.5
V
VLDO33 falling
2.4
V
1mA < ILOAD < 20mA, VLDOIN = 7V
0.25
%
VCC –
1.3
V
24V INTERFACE
C/Q Driver Output-Voltage High
VOH_C/Q
C/Q high-side enabled, IC/Q = -100mA,
9V P VCC P 36V
C/Q Driver Output-Voltage Low
VOL_C/Q
C/Q low-side enabled, IC/Q = +100mA,
9V P VCC P 36V
C/Q Driver Source Current Limit
IOH_C/Q
C/Q high-side enabled, VC/Q < (VCC 3V), 9V P VCC P 36V
C/Q Driver Sink Current Limit
IOL_C/Q
DO Driver Output-Voltage High
VCC 1.3
1.4
3
V
+100
+140
+190
mA
C/Q low-side enabled, VC/Q > 3V,
9V P VCC P 36V
-190
-140
-100
mA
VOH_DO
DO high-side enabled, IDO = +100mA,
9V P VCC P 36V
VCC
-3
VCC 1.6
DO Driver Output-Voltage Low
VOL_DO
DO low-side enabled, IDO = -100mA,
9V P VCC P 36V
DO Driver Source Current Limit
IOH_DO
DO Driver Sink Current Limit
IOL_DO
C/Q, DI Input Voltage Range
VIN
DO high-side enabled, VDO < (VCC - 3V)
DO high-side enabled, VDO > 3V
V
1.6
3
V
+100
+135
+190
mA
-190
-135
-100
mA
V
For valid RX, LI
-1.0
VCC +
1.0
C/Q Input Threshold High
VIH_C/Q
C/Q driver disabled
10.5
13.0
V
C/Q Input Threshold Low
VIL_C/Q
C/Q driver disabled
8.0
11.5
V
VHYS_C/Q
C/Q driver disabled
1.0
C/Q Input Hysteresis
V
DI Input Threshold High
VIH_DI
6.8
8
V
DI Input Threshold Low
VIL_DI
5.2
6.4
V
400
FA
DI Input Hysteresis
C/Q Weak Pulldown Current
VHYS_DI
IPDC/Q
1
C/Q driver disabled, VC/Q = (VCC - 1V)
100
V
�� Maxim Integrated Products 4
MAX14821
IO-Link Device Transceiver
DC ELECTRICAL CHARACTERISTICS (continued)
(VCC = 18V to 36V, VL = 2.3V to 5.5V, VGND = 0V; all logic inputs at VL or GND; TA = -40NC to +85NC, unless otherwise noted. Typical
values are at VCC = 24V, VL = 3.3V, and TA = +25NC, unless otherwise noted.) (Note 2)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
40
120
FA
50
300
FA
DO Weak Pulldown Current
IPDDO
DO driver disabled, VCC = 36V,
VDO = (VCC - 1V)
DI Weak Pulldown Current
IPDDI
DI load disabled, VCC = 36V,
VDI = (VCC - 1V)
C/Q Input Capacitance
CC/Q
C/Q driver disabled
40
pF
DO Input Capacitance
CDO
DO driver disabled
40
pF
DI Input Capacitance
CDI
20
pF
C/Q, DI CURRENT SINK
C/Q Load Current
ILLM_C/Q
DI Load Current
ILLM_DI
C/Q load enabled
(C/QLoad = 1)
DI load enabled
(DiLoad = 1)
0V P VC/Q P 5V
0
5V P VC/Q
0V P VDI P 5V
5
9V P VDI
6
9
6.6
0
9
9
7.5
9
mA
mA
LOGIC INPUTS (TXC, TXQ, TXEN, LO, CS, SDI, SCLK)
Logic-Input Voltage Low
VIL
Logic -Input Voltage High
VIH
Logic-Input Leakage Current
Logic-Input Capacitance
ILEAK
0.3 x
VL
Logic input = GND or VL
V
-1
CIN
0.7 x
VL
V
+1
FA
5
pF
LOGIC OUTPUTS (RX, WU, LI, UV, SDO, IRQ)
Logic-Output Voltage Low
Logic-Output Voltage High
SDO Leakage Current
VOL
IOUT = -5mA
VOHRX,
VOHWU, VOHLI,
IOUT = 5mA (Note 3)
VOHSDO,
VOHIRQ,
ILK_SDO
SDO disabled, SDO = GND or VL
0.4
VL 0.6
V
V
-1
+1
FA
THERMAL SHUTDOWN
Thermal Warning Threshold
Die temperature rising, OTemp bit is set
Thermal Warning Threshold
Hysteresis
Die temperature falling, OTemp bit is
cleared
Thermal Shutdown Threshold
Die temperature rising
Thermal Shutdown Hysteresis
+115
NC
20
NC
+150
NC
20
NC
�� Maxim Integrated Products 5
MAX14821
IO-Link Device Transceiver
AC ELECTRICAL CHARACTERISTICS
(VCC = 18V to 36V, VL = 2.3V to 5.5V, VGND = 0V; all logic inputs at VL or GND; TA = -40NC to +85NC, unless otherwise noted. Typical
values are at VCC = 24V, VL = 3.3V, and TA = +25NC, unless otherwise noted.) (Note 2)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
C/Q, DO, DI INTERFACES
Data Rate
DR
HiSlew = 1
4.8
230.4
HiSlew = 0
4.8
38.4
kbps
DRIVER (C/Q, DO)
Driver Low-to-High Propagation
Delay
tPDLH
Push-pull or high-side (PNP)
configuration, Figure 1
HiSlew = 1
0.5
2
HiSlew = 0
1.6
5
Driver High-to-Low Propagation
Delay
tPDHL
Push-pull or low-side (NPN)
configuration, Figure 1
HiSlew = 1
0.5
2
HiSlew = 0
1.6
5
Driver Skew
tSKEW
|tPDLH - tPDHL|
0.1
2
0.4
1.7
Driver Rise Time
tRISE
Push-pull or high-side (PNP)
configuration, Figure 1
HiSlew = 1
HiSlew = 0
1.5
4
Driver Fall Time
tFALL
Push-pull or low-side (NPN)
configuration, Figure 1
HiSlew = 1
0.4
1.7
HiSlew = 0
1.4
4
Driver Enable Time High
tENH
Push-pull or high-side (PNP)
configuration, Figure 3
HiSlew = 1
0.3
1
HiSlew = 0
0.8
7
Driver Enable Time Low
tENL
Push-pull or low-side (NPN)
configuration, Figure 2
HiSlew = 1
0.3
1
HiSlew = 0
0.9
7
Driver Disable Time High
tDISH
Push-pull or high-side (PNP)
configuration, Figure 2
(Note 4)
HiSlew = 1
1.6
3
HiSlew = 0
1.6
3
Driver Disable Time Low
tDISL
Push-pull or low-side (NPN)
configuration, Figure 3
(Note 4)
HiSlew = 1
0.1
3
HiSlew = 0
0.1
3
RxFilter = 1
0.2
2
RxFilter = 0
0.4
2
RxFilter = 1
0.3
2
RxFilter = 0
0.5
2
Fs
Fs
Fs
Fs
Fs
Fs
Fs
Fs
Fs
RECEIVER (C/Q, DI) (Figure 4)
Receiver Low-to-High
Propagation Delay
tPRLH
Receiver High-to-Low
Propagation Delay
tPRHL
Fs
Fs
WAKE-UP DETECTION (Figure 5)
Wake-Up Input Minimum Pulse
Width
tWUMIN
30
40
50
Fs
Wake-Up Input Maximum Pulse
Width
tWUMAX
120
140
160
Fs
120
190
260
Fs
WU Output Low Time
tWUL
Valid wake-up condition on C/Q
�� Maxim Integrated Products 6
MAX14821
IO-Link Device Transceiver
AC ELECTRICAL CHARACTERISTICS (continued)
(VCC = 18V to 36V, VL = 2.3V to 5.5V, VGND = 0V; all logic inputs at VL or GND; TA = -40NC to +85NC, unless otherwise noted. Typical
values are at VCC = 24V, VL = 3.3V, and TA = +25NC, unless otherwise noted.) (Note 2)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
SPI TIMING (CS, SCLK, SDI, SDO) (Figure 6)
SCLK Clock Period
tCH+CL
83.3
ns
tCH
41.65
ns
SCLK Pulse-Width Low
tCL
41.65
ns
CS Fall to SCLK Rise Time
tCSS
20
ns
SCLK Rise to CS Rise Hold Time
tCSH
20
ns
SDI Hold Time
tDH
10
ns
SDI Setup Time
tDS
10
ns
Output Data Propagation Delay
tDO
32
ns
SDO Rise and Fall Times
tFT
20
ns
SCLK Pulse-Width High
Minimum CS Pulse
tCSW
76.8
ns
Note 2: All devices are 100% production tested at TA = +25NC. Limits over the operating temperature range are guaranteed by
design.
Note 3: UV is an open-drain output. Connect UV to a voltage less than 5.5V through an external pullup resistor.
Note 4: Disable time measurements are load dependent.
�� Maxim Integrated Products 7
MAX14821
IO-Link Device Transceiver
TXEN
TXC
C/Q OR DO
MAX14821
TXQ
3.3nF
5kΩ
LO
GND
VL
TXEN
0V
VL
(TXC AND TXQ)
OR LO
50%
tPDHL
0V
tPDLH
C/Q OR DO
tFALL
VCC
90%
50%
10%
0V
tRISE
Figure 1. C/Q and LO Driver Propagation Delays and Rise/Fall Times
VCC
5kΩ
TXEN
C/Q
VL
3.3nF
MAX14821
TXC
TXQ
GND
VL
TXEN
tENL
0V
tDISH
VCC
C/Q
10%
10%
0V
Figure 2. C/Q Driver Enable Low and Disable High Timing with External Pullup Resistor
�� Maxim Integrated Products 8
MAX14821
IO-Link Device Transceiver
TXEN
C/Q
MAX14821
TXC
3.3nF
5kΩ
TXQ
GND
VL
TXEN
0V
tDISL
tENH
C/Q
VCC
90%
90%
0V
Figure 3. C/Q Driver Enable High and Disable Low Timing
RX OR LI
C/Q OR DI
15pF
MAX14821
GND TXEN
VCC
C/Q OR DI
50%
tPRLH
0V
tPRHL
VL
RX OR LI
50%
0V
Figure 4. C/Q and DI Receiver Propagation Delays
�� Maxim Integrated Products 9
MAX14821
IO-Link Device Transceiver
TXEN
WU
TXC AND TXQ
MAX14821
C/Q
GND
TXEN
TXC AND TXQ
< tWUMIN
NO WAKE-UP
C/Q
tWUMIN < tWU < tWUMAX
WU
tWUL
NOTE: THE MAX14821 RECOGNIZES A WAKE-UP PULSE WHEN C/Q IS SHORTED FROM HIGH-TO-LOW OR FROM LOW-TO-HIGH FOR tWUMIN < tWU < tWUMAX.
Figure 5. Wake-Up Detection Timing
CS
tCSS
tCSH
tCH
tCSH
tCL
SCLK
tDS
tDH
SDI
tDO
SDO
Figure 6. SPI Timing Diagram
�� Maxim Integrated Products 10
MAX14821
IO-Link Device Transceiver
Typical Operating Characteristics
(VCC = 24V, LDOIN = VP, VL = LDO33, C/Q and DO in push-pull configuration, TA = +25NC, unless otherwise noted.)
C/Q DRIVER OUTPUT HIGH
vs. LOAD CURRENT
C/Q DRIVER OUTPUT LOW
vs. SINK CURRENT
23
6
5
22
VOL_C/Q (V)
TA = -40°C
0
25
50
75
100
125
150
0
175
25
50
75
100
125
LOAD CURRENT (mA)
SINK CURRENT (mA)
DO DRIVER OUTPUT HIGH
vs. LOAD CURRENT
DO DRIVER OUTPUT LOW
vs. SINK CURRENT
TA = +85°C
23
175
150
175
7
MAX14821 toc03
24
150
MAX14821 toc04
0
6
5
22
TA = -40°C
21
VOL_DO (V)
VOH_DO (V)
TA = -40°C
1
18
TA = +25°C
4
TA = +85°C
TA = +25°C
3
TA = -40°C
20
2
19
1
0
18
0
25
50
75
100
125
150
0
175
25
50
75
100
125
LOAD CURRENT (mA)
SINK CURRENT (mA)
C/Q DRIVER PROPAGATION DELAY
vs. TEMPERATURE (HiSlew = 0)
C/Q DRIVER PROPAGATION DELAY
vs. TEMPERATURE (HiSlew = 1)
0.46
MAX14821 toc05
1.30
1.28
1.26
0.45
0.44
1.24
1.22
tPDHL (µs)
tPDHL (µs)
TA = +25°C
2
19
1.20
1.18
0.43
0.42
0.41
1.16
0.40
1.14
1.10
TA = +85°C
3
TA = +25°C
20
1.12
4
MAX14821 toc06
VOH_C/Q (V)
TA = +85°C
21
MAX14821 toc02
7
MAX14821 toc01
24
0.39
TXEN = VL
TXC = TXQ
-45 -30 -15
0.38
0
15
30
45
TEMPERATURE (°C)
60
75
90
TXEN = VL
TXC = TXQ
-45 -30 -15
0
15
30
45
60
75
90
TEMPERATURE (°C)
�� Maxim Integrated Products 11
MAX14821
IO-Link Device Transceiver
Typical Operating Characteristics (continued)
(VCC = 24V, LDOIN = VP, VL = LDO33, C/Q and DO in push-pull configuration, TA = +25NC, unless otherwise noted.)
C/Q DRIVER OUTPUT SWITCHING
(HiSlew = 0)
C/Q DRIVER OUTPUT SWITCHING
(HiSlew = 1)
MAX14821 toc07
MAX14821 toc08
VTXC=TXQ
2V/div
Ch1 Ch2
1.430µs
0V
Ch1 Ch2
1.330µs
VC/Q
5V/div
Ch2 RISE
1.583µs
VTXC=TXQ
2V/div
Ch1 Ch2
357.1ns
0V
Ch1 Ch2
335.4ns
VC/Q
5V/div
Ch2 RISE
343.5ns
Ch2 FALL
1.455µs
Ch2 FALL
331.7ns
0V
0V
2µs/div
2µs/div
RECEIVER PROPAGATION DELAY
vs. TEMPERATURE (RxFilter = 0)
RECEIVER PROPAGATION DELAY
vs. TEMPERATURE (RxFilter = 1)
400
DI TO LI
350
C/Q TO RX
350
300
tPRHL (ns)
450
300
250
200
150
250
200
100
150
50
100
MAX14821 toc10
500
tPRHL (ns)
400
MAX14821 toc09
550
DI TO LI
C/Q TO RX
0
-45 -30 -15
0
15
30
45
60
75
-45 -30 -15
90
TEMPERATURE (°C)
0
15
30
WAKE-UP DETECTION
60
75
90
C/Q SHORT-CIRCUIT PROTECTION
MAX14821 toc11
MAX14821 toc12
C/Q
10V/div
VC/Q
10V/div
0V
VWU
2V/div
0V
40µs/div
45
TEMPERATURE (°C)
ISOURCE
100mA/div
TXEN = VL
TXC = TXQ = GND
tSHORT = 200µs
IRQ
2V/div
40µs
�� Maxim Integrated Products 12
MAX14821
IO-Link Device Transceiver
Typical Operating Characteristics (continued)
(VCC = 24V, LDOIN = VP, VL = LDO33, C/Q and DO in push-pull configuration, TA = +25NC, unless otherwise noted.)
LDOIN SUPPLY CURRENT
vs. LDOIN VOLTAGE
C/Q SHORT-CIRCUIT PROTECTION
MAX14821 toc13
3.5
C/Q
10V/div
3.0
ILDOIN (mA)
ISINK
100mA/div
MAX14821 toc14
4.0
2.5
2.0
1.5
VCC = 36V
C/Q AND DO DRIVERS ENABLED
V5, LDO33 ARE LOADED
TXC = TXQ = LO = VL
1.0
TXEN = VL
TXQ = TXC = VL
tSHORT = 200µs
IRQ
2V/div
TA = +85°C
TA = +25°C
TA = -40°C
0.5
0
9
40µs
12
15
18
21
24
27
30
33
36
VLDOIN (V)
V5 LOAD REGULATION
TA = -40°C
TA = +25°C
-0.15
-0.20
TA = +85°C
-0.25
-0.30
-0.35
-0.40
-0.2
-0.3
TA = +25°C
-0.4
-0.5
TA = +85°C
-0.6
-0.45
-0.7
-0.50
10
20
30
40
12
10 15 20 25 30 35 40 45 50
LOAD CURRENT (mA)
VCC SUPPLY CURRENT
vs. C/Q DATA RATE
VCC SUPPLY CURRENT
vs. VCC VOLTAGE
1.8
MAX14821 toc17
VLDOIN = V5 = 5V
TXEN = VL
HiSlew = 1
NO LOAD ON C/Q
14
5
LOAD CURRENT (mA)
18
16
0
50
TA = +25°C
1.6
1.4
ICC (mA)
1.2
10
VCC = 36V
8
VCC = 30V
6
4
TA = +85°C
1.0
VLDOIN = 7V
C/Q AND DO DRIVERS ENABLED
V5, VP UNLOADED
C/Q AND DI CURRENT LOADS OFF
TXC = TXQ = LO = VL
0.4
2
0.2
0
1
10
100
C/Q DATA RATE (kbps)
1k
TA = -40°C
0.8
0.6
VCC = 24V
MAX14821 toc18
0
ICC (mA)
TA = -40°C
-0.1
% VOLTAGE CHANGE
% VOLTAGE CHANGE
-0.10
MAX14821 toc16
-0.05
LDO33 LOAD REGULATION
0
MAX14821 toc15
0
0
9
12
15
18
21
24
27
30
33
36
VCC VOLTAGE (V)
�� Maxim Integrated Products 13
MAX14821
IO-Link Device Transceiver
Pin/Bump Configurations
TOP VIEW
(BUMP SIDE DOWN)
UV
LI
LO
WU
RX
TXEN
TOP VIEW
18
17
16
15
14
13
12 TXC
GND 20
11 TXQ
10 I.C.
MAX14821
DO 22
VCC 23
*EP
+
1
2
3
4
5
6
LDOIN
V5
LDO33
IRQ
SCLK
CS
VP 24
1
2
3
4
5
A
VCC
LDOIN
V5
LDO33
SCLK
B
C/Q
VP
IRQ
CS
SDO
C
GND
GND
I.C.
SDI
VL
D
DO
UV
WU
TXC
TXQ
E
DI
LI
LO
RX
TXEN
+
DI 19
C/Q 21
MAX14821
9
VL
8
SDI
7
SDO
WLP
TQFN
*CONNECT EXPOSED PAD TO GND.
Pin/Bump Descriptions
PIN
TQFN-EP
WLP
1
A2
NAME
LDOIN
FUNCTION
5V Linear Regulator Input. Bypass LDOIN to GND with a 0.1FF ceramic capacitor.
5V Power-Supply Input and 5V Linear Regulator Output. Bypass V5 to GND with a 0.1FF
ceramic capacitor for 10mA load capability. Add the recommended compensation network
to increase the source capability to 30mA. See the 5V and 3.3V Linear Regulators section for
more information.
2
A3
V5
3
A4
LDO33
4
B3
5
A5
IRQ
SCLK
Active-Low Interrupt Request Output. IRQ is a push-pull output referenced to VL.
SPI Clock Input
6
B4
B5
CS
SDO
Active-Low SPI Chip-Select Input
7
8
C4
SDI
SPI Serial-Data Input
9
C5
VL
Logic-Level Supply Input. VL defines the logic levels on all the logic inputs and outputs.
Bypass VL to GND with a 0.1FF ceramic capacitor.
10
C3
I.C.
Internally Connected. Connect to VL or leave unconnected.
3.3V Linear Regulator Output. Bypass LDO33 to GND with a 1FF ceramic capacitor.
SPI Serial-Data Output
�� Maxim Integrated Products 14
MAX14821
IO-Link Device Transceiver
Pin/Bump Descriptions (continued)
PIN
NAME
FUNCTION
TQFN-EP
WLP
11
D5
TXQ
Transmit Level Input. The logic on the C/Q output is the inverse logic level of the signals on
the TXC and TXQ inputs. TXQ is ANDed with TXC. Drive TXQ high if not in use.
12
D4
TXC
Transmit Communication Input. The logic on the C/Q output is the inverse logic level of the
signals on the TXC and TXQ inputs. TXC is ANDed with TXQ. Drive TXC high if not in use.
13
E5
TXEN
Transmitter Enable. Drive TXEN high to enable the C/Q transmitter. TXEN is referenced to VL.
14
E4
RX
Receiver Output. RX is the inverse logic level of C/Q. RX is always high when the RxDis bit in
the CQConfig register is set to 1.
15
D3
WU
Active-Low Wake-Up Output. WU is a push-pull output referenced to VL. WU pulses low for
190Fs (typ) when a valid wake-up pulse is detected on the C/Q line.
16
E3
LO
17
E2
LI
18
D2
UV
Open-Drain Undervoltage Indicator Output. In case of an undervoltage, the UV open-drain
transistor is off.
24V Logic-Level Digital Input
Logic Input of the DO Output. LO is the logic input that drives DO. LO is referenced to VL.
Logic Output of the 24V DI Logic Input. LI is the inverse logic of DI. LI is referenced to VL.
19
E1
DI
20
C1, C2
GND
Ground
21
B1
C/Q
SIO/IO-Link Data Input/Output. Drive TXEN high to enable the C/Q driver. The logic on the
C/Q output is the inverse logic level of the signals on the TXC and TXQ inputs. RX is the logic
inverse of C/Q. The C/Q driver output level can be set by the TXC/TXQ inputs or programmed
by the Q bit. The level on C/Q can be read by the RX ouput or the QLvl bit.
22
D1
DO
24V Logic-Level Digital Output. DO is the inverse logic level of the LO input and can be digitally controlled through the DIOConfig register.
23
A1
VCC
Power-Supply Input. Bypass VCC to GND with a 1FF ceramic capacitor.
24
B2
VP
Protected 24V Supply Output. VP is one diode drop below VCC. VP is reverse-polarity protected and can be used as a 24V protected supply to the sensor or actuator electronics.
—
—
EP
Exposed Pad (TQFN Only). Connect EP to GND.
�� Maxim Integrated Products 15
MAX14821
IO-Link Device Transceiver
Detailed Description
The MAX14821 is a sensor/actuator transceiver designed
for IO-Link device applications supporting all the specified IO-Link data rates. In IO-Link applications, the
device acts as the physical layer interface to a microcontroller running the data-link layer protocol. The device
contains an additional 24V digital input and an additional
24V digital output. Two internal linear regulators generate common sensor and actuator power requirements:
5V and 3.3V.
The device detects IO-Link wake-up conditions on the C/Q
line and generates a wake-up signal on the WU output.
The C/Q and DO drivers are independently configurable to
any one of three driver output types: push-pull, high-side
(PNP), or low-side (NPN).
The C/Q and DI inputs have selectable current sinks that
can be enabled for use in actuators where the master
requires a Type 2 load. The device is configured and
monitored through an SPI interface. Extensive alarms are
available through SPI.
24V Interface
The device features an IO-transceiver interface capable
of operating with voltages up to 36V. This is the 24V interface and includes the C/Q input/output, the logic-level
digital output (DO), and the logic-level digital input (DI).
Configurable Drivers
The device features selectable push-pull, high-side (PNP),
or low-side (NPN) switching drivers at C/Q and DO.
Set the C/Q_N/P and C/Q_PP bits in the CQConfig register to select the driver mode for the C/Q driver. When
configured as a push-pull output, C/Q switches between
VP and ground. Set the C/Q_PP bit to 1 to select pushpull operation at C/Q. Set the C/Q_PP bit to 0 to configure
the C/Q output for open-drain operation. The C/Q_N/P bit
selects NPN or PNP operation when C/Q is configured as
an open-drain output.
Set the DoN/P and DoPP bits in the DIOConfig register
to select the driver mode for the DO output. When configured as a push-pull output, DO switches between VCC
and ground. Set the DoPP bit to 1 for push-pull operation.
The DoN/P bit selects NPN or PNP operation when DO is
configured as an open-drain output. Set the DoPP bit to 0
to select high-side or low-side operation at DO.
C/Q Driver and Receiver
The TXEN input enables the C/Q driver. Drive TXEN high
to enable the C/Q driver. Drive TXEN low to disable the
driver.
The C/Q driver is specified to supply up to 100mA DC
load current.
The HiSlew bit increases the slew rate of the C/Q and DO
driver outputs. Set HiSlew to 1 for data rates of 230kbps
or higher. Set HiSlew to 0 to reduce both the C/Q and DO
driver slew rates to reduce EMI emission and reflections.
The C/Q receiver is always on. Disable the RX output
through the RxDis bit in the CQConfig register. Set the
RxDis bit to 1 to set the RX output high. Set the RxDis bit
to 0 for normal receive operation.
The C/Q receiver has an analog lowpass filter to reduce
high-frequency noise present on the line. Set the RxFilter
bit in the CQConfig register to 0 to set the filter corner
frequency to 500kHz (typ). Set the RxFilter bit to 1 to set
the corner frequency of the filter to 1MHz (typ). Noise
filters are present on both the C/Q and DI receivers and
are controlled simultaneously by the RxFilter bit.
C/Q Fault Detection
The device registers a C/QFault condition under either of
two conditions:
1) When it detects a short circuit for longer than 160µs
(typ). A short condition exists when the C/Q driver’s
load current exceeds the 140mA (typ) current limit.
2) When it detects a voltage level error at the C/Q output. A voltage level error occurs when the C/Q driver
is configured for open-drain operation (NPN or PNP),
the driver is turned off, and the C/Q voltage is not
pulled to exceed the C/Q receiver’s threshold levels
(< 8V or > 13V) by the external supply.
When a C/QFault error occurs, the C/QFault and
C/QFaultInt bits are set, IRQ asserts, and the driver is
turned off 240µs (typ) after the start of the fault condition.
When a short-circuit event occurs on C/Q, the driver
enters autoretry mode. In autoretry mode the device
periodically checks whether the short is still present and
attempts to correct the driver output. Autoretry attempts
last for 350µs (typ) and occur every 26ms (typ).
�� Maxim Integrated Products 16
MAX14821
IO-Link Device Transceiver
DO Fault Detection
The device registers a DoFault event when a short circuit
is present at the DO output for 440Fs. A short condition
exists when the load current on the DO driver exceeds
the 135mA (typ) DO current limit. When a short-circuit
condition is detected, the DO driver enters autoretry
mode. In autoretry mode the device periodically checks
whether the error is still present. Autoretry attempts last
for 440µs (typ) and occur every 26ms (typ). When a
DoFault error is detected, the DoFault and DoFaultInt bits
are set, IRQ asserts, and the driver is turned off 440µs
(typ) after the start of the DO faults.
Reverse-Polarity Protection
The device is protected against reverse-polarity connections on VCC, C/Q, DO, DI, and GND. Any combination
of these pins can be connected to DC voltages up to
40V (max). A short to 40V results in a current flow of less
than 500FA.
Ensure that the maximum voltage between any of these
pins does not exceed 40V.
5V and 3.3V Linear Regulators
The device includes two internal current-limited regulators
to generate 5V (V5) and 3.3V (LDO33). V5 is specified at
10mA when bypassed with a 0.1µF capacitor to ground.
Add the compensation network shown in Figure 7 to draw
up to 30mA from V5. LDO33 is specified at 20mA. The
input of V5, LDOIN, can be connected to VP, the protected 24V supply output, or to another voltage in the 7V
to 36V range.
V5 constitutes the supply for the logic block. The 5V LDO
can be disabled by connecting LDOIN to V5. Apply an
external voltage from 4.75V to 5.25V to V5 when the LDO
is disabled.
V5
5V
0.1µF
10Ω
MAX14821
1µF
LDO33
VL
Figure 7. V5 Compensation Network
3.3V
1 µF
Use the LDO33Dis bit in the Mode register to enable/
disable LDO33. See the Mode Register [R1, R0] = [1,1]
section for more information. V5 and LDO33 are not protected against short circuits.
Power-Up
The C/Q and DO driver outputs and the UV output are
high impedance when VCC, V5, VL, and/or LDO33 voltages are below their respective undervoltage thresholds during power-up. UV goes low and the drivers are
enabled when all these voltages exceed their respective
undervoltage-lockout thresholds.
The drivers are automatically disabled if VCC, V5, or VL
falls below its threshold.
Undervoltage Detection
The device monitors VCC, V5, VL, and optionally LDO33
for undervoltage conditions. UV is high impedance when
any monitored voltage falls below its UVLO threshold.
VCC, V5, and VL undervoltage detection cannot be disabled. When VCC falls below the VCCUVLO threshold, the
UV24 and UV24Int bits are set, UV asserts high, and IRQ
asserts low.
The SPI register contents are unchanged while V5 is present, regardless of the state of VCC and LDO33. The SPI
interface is not accessible and IRQ is not available when
UV is asserted due to a V5 or VL undervoltage event.
When the internal 3.3V LDO regulator voltage (VLDO33)
falls below the LDO33 undervoltage-lockout threshold,
the UV33Int bit in the Status register is set and IRQ
asserts. UV asserts if the UV33En bit in the Mode register
is set to 1.
The UV output deasserts once the undervoltage condition is removed; however, bits in the Status register and
the IRQ output are not cleared until the Status register
has been read.
Wake-Up Detection
The device detects an IO-Link wake-up condition on the
C/Q line in push-pull, high-side (PNP), or low-side (NPN)
operation modes. A wake-up condition is detected when
the C/Q output is shorted for 80Fs (typ). WU pulses low
for 190Fs (typ) when the device detects a wake-up pulse
on C/Q (Figure 5).
Set the WuIntEn bit in the Mode register to set the WuInt
bit in the Status register and generate an interrupt on
IRQ when a wake-up pulse is detected. WuInt is set
and IRQ asserts immediately after C/Q is released when
WuIntEn = 1.
�� Maxim Integrated Products 17
MAX14821
IO-Link Device Transceiver
Thermal Protection and Considerations
The internal LDOs and drivers can generate more power
than the package for the device can safely dissipate.
Ensure that the driver LDO loading is less than the package can dissipate. Total power dissipation for the device
is calculated using the following equation:
PTOTAL = PC/Q + PDO + P5 + PLDO33 + PQ +
PCLCQ + PCLDI
Calculate the quiescent power dissipation in the device
using the following equation:
PQ = 5mA × VCC(max)
If the current sinks are enabled, calculate their associated power dissipation as:
PCLCQ = 7mA × VC/Q(max)
PCLDI = 7mA × VDI(max)
where PC/Q is the power generated in the C/Q driver,
PDO is the power dissipated by the DO driver, P5 and
PLDO33 are the power generated by the LDOs, PQ is the
quiescent power generated by the device, and PCLCQ
and PCLDI are the power generated in the C/Q and DI
current sinks.
Overtemperature Warning
Bits in the Status and Mode registers are set when the
temperature of the device exceeds +115NC (typ). The
OTempInt bit in the Status register is set and IRQ asserts
when the OTemp bit in the Mode register is set. Read the
Status register to clear the OTempInt bit and IRQ.
Ensure that the total power dissipation is less than the
limits listed in the Absolute Maximum Ratings section.
The OTemp bit is cleared when the die temperature falls
to +95NC.
Use the following to calculate the power dissipation (in
mW) due to the C/Q driver:
The device continues to operate normally unless the
die temperature reaches the +150NC thermal shutdown
threshold, when the device enters thermal shutdown.
PC/Q = [IC/Q(max)] × [0.5 + 7 × IC/Q(max)]
Calculate the internal power dissipation of the DO driver
using the following equation:
PDO = [IDO(max)] × [0.5 + 7 × IDO(max)]
Calculate the power dissipation in the 5V LDO, V5, using
the following equation:
P5 = (VLDOIN - V5) × I5
where I5 includes the ILDO33 current sourced from
LDO33.
Calculate the power dissipated in the 3.3V LDO, LDO33,
using the following equation:
PLDO33 = 1.7V × ILDO33
Thermal Shutdown
When the die temperature rises above the +150°C (typ)
thermal shutdown threshold, the C/Q and DO drivers and
the C/Q and DI current loads are automatically turned off.
The internal 3.3V and 5V LDOs remain on during thermal
shutdown, if enabled. If the internal or external V5 supply
remains on during thermal shutdown (which is always
true in case of the internal V5 regulator), the register contents are maintained and SPI communication is available.
When the die temperature falls below the thermal shutdown threshold plus hysteresis, the C/Q and DO drivers
and C/Q and DI current sinks turn on automatically.
�� Maxim Integrated Products 18
MAX14821
IO-Link Device Transceiver
Register Functionality
The device has four 8-bit-wide registers for configuration and monitoring (Table 1).
Table 1. Register Summary
REGISTER
R1
R0
D7
D6
D5
D4
D3
D2
D1
D0
Status
0
0
WuInt
DoFaultInt
DiLvl
C/QFaultInt
UV33Int
UV24Int
OTempInt
CQConfig
0
1
RxFilter
HiSlew
C/Q_N/P
QLvl
C/Q_PP
C/QDEn
Q
RxDis
C/QLoad
DIOConfig
1
0
DoInv
DoAv
DoN/P
DoPP
DoEn
DoBit
LiDis
DiLoad
Mode
1
1
RST
WuIntEn
DoFault
C/QFault
UV24
OTemp
UV33En
LDO33Dis
R1/R0 = Register address.
Status Register [R1, R0] = [0,0]
Bit
Bit Name
Read/Write
POR State
Reset Upon Read
D7
D6
D5
D4
D3
D2
D1
D0
WuInt
DoFaultInt
DiLvl
C/QFaultInt
UV33Int
UV24Int
OTempInt
R
R
R
QLvl
R
R
R
R
R
0
0
X
X
0
0
0
0
Yes
Yes
No
No
Yes
Yes
Yes
Yes
X = Unknown. These bits are dependent on the DI logic and C/Q inputs.
The Status register reflects the logic levels of C/Q and DI and shows the source of interrupts that cause an IRQ
hardware interrupt. The IRQ interrupt is asserted when an alarm condition (OTemp, UV33Int, UV24, C/QFault,
DoFault, WuInt) is detected. All bits in the Status register are read-only. The interrupt bits return to the default state
after the Status register is read. If a C/Q or DO fault condition persists, the associated interrupt bits are immediately
set after the Status register is read.
BIT
NAME
DESCRIPTION
D7
Wulnt
Wake-Up Interrupt Request. WuInt is set when an IO-Link wake-up request pulse is
detected on C/Q and the WuIntEn bit in the Mode register is set. IRQ asserts when
WuInt is set to 1. Read the Status register to clear the WuInt bit and deassert IRQ.
D6
DoFaultInt
DO Fault Interrupt. DoFaultInt interrupt bit and DoFault bit (in the Mode register) are
set when a fault condition occurs on the DO driver output. The device registers a fault
condition when a short circuit or voltage fault is detected on DO (see the DO Fault
Detection section for more information). IRQ asserts when DoFaultInt is 1. Read the
Status register to clear the DoFaultInt bit and deassert IRQ.
D5
DiLvl
DI Logic Level. The DiLvl bit mirrors the current logic level at the DI input. It is the
inverse of the LI output and is always active regardless of the state of the LiDis bit (Table
2). DiLvl does not affect IRQ. DiLvl is not changed when the Status register is read.
�� Maxim Integrated Products 19
MAX14821
IO-Link Device Transceiver
BIT
NAME
DESCRIPTION
D4
QLvl
C/Q Logic Level. The QLvl bit is the inverse of the logic level at C/Q. QLvl is 1 when the
C/Q input level is low (< 8V) and is 0 when the C/Q logic level is high (> 13V) (Table 3).
QLvl remains active when the C/Q receiver is disabled (RxDis = 1). QLvl does not affect
IRQ. QLvl is not changed when the Status register is read.
D3
C/QFaultInt
C/Q Fault Interrupt. The C/QFaultInt interrupt bit and C/QFault bit (in the Mode register)
are set when a short circuit or voltage fault occurs on the C/Q driver output (see the C/Q
Fault Detection section for more information). IRQ asserts when C/QFault is 1. Read the
Status register to clear the C/QFaultInt bit and deassert IRQ.
D2
UV33Int
Internal 3.3V LDO (LDO33) Undervoltage Warning. Both the UV33Int interrupt bit and
the UV33En bit (in the Mode register) are set when VLDO33 falls below the 2.4V LDO33
undervoltage threshold. If UV33En is set in the Mode register, IRQ asserts low when the
UV33Int bit is 1. Read the Status register to clear the UV33Int bit and deassert IRQ.
Set the UV33En bit to 1 in the Mode register to enable undervoltage monitoring for
UV33Int. When enabled, UV asserts high when the UV33Int bit is 1. UV deasserts when
VLDO33 rises above the LDO33 undervoltage threshold.
D1
UV24Int
VCC Undervoltage Interrupt. The UV24Int interrupt bit and the UV24 bit (in the Mode
register) are set when the VCC voltage falls below the 7.4V undervoltage threshold. IRQ
asserts low when the UV24Int bit is 1. Read the Status register to clear the UV24Int bit
and deassert IRQ. VCC undervoltage detection cannot be disabled.
D0
OTempInt
Overtemperature Warning. The OTempInt interrupt bit and the OTemp bit (in the Mode
register) are set when a high-temperature condition is detected by the device. OTemp
is set when the temperature of the die exceeds +115NC (typ). OTempInt is set and IRQ
asserts when the OTemp bit is 1. The OTempInt bit is cleared and IRQ deasserts when
the Status register is read.
Once cleared, OTempInt is not reset if the die temperature remains above the thermal
warning threshold and does not fall below +95°C.
Table 2. DiLvl and LI Output
Table 3. QLvl and RX Output
VDI (V)
DiLvl BIT
LI OUTPUT
VC/Q (V)
QLvl BIT
RX OUTPUT
< 5.2
0
High
<8
1
High
>8
1
Low
>13
0
Low
�� Maxim Integrated Products 20
MAX14821
IO-Link Device Transceiver
CQConfig Register [R1, R0] = [0,1]
Bit
D7
D6
D5
D4
D3
D2
D1
D0
RxFilter
HiSlew
C/Q_N/P
C/Q_PP
C/QDEn
Q
RxDis
C/QLoad
Read/Write
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
POR State
0
0
0
0
0
0
0
0
Bit Name
Use the CQConfig register to control the C/Q receiver and driver parameters. All bits in the CQConfig register are
read-write and are set to 0 at power-up.
BIT
NAME
D7
RxFilter
DESCRIPTION
C/Q and DI Receiver Filter Control. The C/Q and DI receivers have analog
lowpass filters to reduce high-frequency noise on the receiver inputs. Set the
RxFilter bit to 0 to set the filter corner frequency to 500kHz. Set the RxFilter
bit to 1 to set the filter corner frequency to 1MHz (this setting is used for highspeed COM3 operation).
Noise filters on C/Q and DI are controlled simultaneously by the RxFilter bit.
D6
HiSlew
Slew-Rate Control. The HiSlew bit increases the slew rate for the C/Q and
DO drivers and is used for high-speed COM3 (230kbps) data rates. Set
HiSlew to 0 for COM1 and COM2 operation.
D5
C/Q_N/P
C/Q Driver NPN/PNP Mode. The C/Q_N/P bit selects between low-side (NPN)
and high-side (PNP) modes when the C/Q driver is configured as an opendrain output (C/Q_PP = 0). Set C/Q_N/P to 1 to configure the driver for low-side
(NPN) operation. Set C/Q_N/P to 0 for high-side (PNP) operation.
D4
C/Q_PP
C/Q Driver Push-Pull Operation. Set C/Q_PP to 1 to enable push-pull
operation on the C/Q driver. The C/Q output is open-drain when C/Q_PP is 0.
D3
C/QDEn
C/Q Driver Enable/Disable. Set the C/QDEn bit to 1 to enable the C/Q driver.
Set C/QDEn to 0 for hardware (TXEN) control. See Table 4.
D2
Q
C/Q Driver Output Logic. The Q bit can be used to program the C/Q output
driver through software. The C/Q driver must be enabled and TXC = TXQ must
be high to control the C/Q driver through the Q bit (Figure 8). C/Q has the
same logic polarity as the Q bit.
Set the Q bit to 0 to control the C/Q driver with TXC and TXQ.
The C/Q driver output state depends on the C/Q_PP and C/Q_N/P bits as
shown in Table 5. Note that Table 5 assumes that the C/Q driver is enabled
(TXEN = VL or C/QDEn = 1).
D1
RxDis
D0
C/QLoad
C/Q Receiver Enable/Disable. Set the RxDis bit to 1 to disable the C/Q
receiver. The RX output is high when RxDis is 1.
C/Q Current Sink Enable. Set the C/QLoad bit to 1 to enable the internal
current sink at C/Q.
�� Maxim Integrated Products 21
MAX14821
IO-Link Device Transceiver
Table 4. C/QDEn and TXEN C/Q Driver
Control
C/QDEn
TXEN
C/Q DRIVER
0
Low
Disabled
X
High
Enabled
1
X
Enabled
X = Don’t care.
TXQ
TXC
C/Q
Q
Figure 8. Equivalent C/Q Logic
Table 5. C/Q Driver Output State
TXC AND TXQ
(SEE NOTE)
Q
C/Q_PP
C/Q_N/P
C/Q CONFIGURATION
High
1
0
0
PNP, open drain
On, C/Q is high
High
0
0
0
PNP, open drain
Off, C/Q is high impedance
High
1
0
1
NPN, open drain
Off, C/Q is high impedance
High
0
0
1
NPN, open drain
On, C/Q is low
High
1
1
X
Push-pull
High
High
0
1
X
Push-pull
Low
C/Q STATE
Note: TXC and TXQ = VL.
X = Don’t care.
�� Maxim Integrated Products 22
MAX14821
IO-Link Device Transceiver
DIOConfig Register [R1, R0] = [1,0]
Bit
D7
D6
D5
D4
D3
D2
D1
D0
DoInv
DoAv
DoN/P
DoPP
DoEn
DoBit
LiDis
DiLoad
Read/Write
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
POR State
0
0
0
0
0
0
0
0
Bit Name
Use the DIOConfig register to control the DI and DO interfaces. All bits in the DIOConfig register are read-write and
are set to 0 at power-up.
BIT
NAME
DESCRIPTION
D7
DoInv
DO Output Polarity. Set the DoInv bit to 1 to invert the logic of the DO
output. This bit also works in conjunction with the DoAv (Table 6). DO
tracks the TXC and TXQ inputs with the opposite polarity when both the
DoAv and DoInv bits are set.
D6
DoAv
DO Antivalent Operation. Set the DoAv bit to 1 to enable antivalent
output operation on DO. DO tracks the TXC and TXQ inputs (and the Q
bit) when DoAv is 1 (Table 6).
D5
DoN/P
DO Driver NPN/PNP Operation. The DoN/P bit selects between lowside (NPN) and high-side (PNP) modes when the DO driver is configured
as an open-drain output (DoPP = 0). Set DoN/P to 1 to configure the
driver for low-side (NPN) operation. Set DoN/P to 0 for high-side (PNP)
operation.
D4
DoPP
DO Driver Push-Pull Operation. Set the DoPP bit to 1 to configure the
DO driver output for push-pull operation. DO is an open-drain output
when DoPP is 0.
D3
DoEn
DO Driver Enable/Disable. Set the DoEn bit to 1 to enable the DO
driver. The DO driver is high impedance with a weak pulldown when
DoEn is 0.
D2
DoBit
DO Driver Output Logic. The DoBit bit can be used to program the
DO output driver through software. Drive LO high to activate DoBit
programming (Figure 9). The DO output state is given in Table 7. Note
that Table 7 assumes that the DoInv bit is 0.
D1
LiDis
LI Output Enable/Disable. Set the LiDis bit to 1 to disable the LI output.
The LI output is low when LiDis is 1.
D0
DiLoad
The LO input and the DoBit are ignored when the DoAv bit is 1.
DI Current Sink Enable. Set the DiLoad bit to 1 to enable the internal
current sink at the DI input.
�� Maxim Integrated Products 23
MAX14821
IO-Link Device Transceiver
Table 6. DoAv and DoInv Operation
DoAv
DoInv
TXC AND TXQ
(NOTE 1)
LO
(NOTE 1)
DO
(NOTE 2)
C/Q
(NOTE 2)
0
0
0
0
Low
Low
High
High
Low
High
Low
0
High
0
High
Low
High
Low
0
0
High
High
Low
Low
0
1
Low
Low
Low
High
0
1
Low
High
High
High
0
1
High
Low
Low
Low
0
1
High
High
High
Low
1
0
Low
Low
Low
High
1
0
Low
High
Low
High
1
0
High
Low
High
Low
1
0
High
High
High
Low
1
1
Low
Low
High
High
1
1
Low
High
High
High
1
1
High
Low
Low
Low
1
1
High
High
Low
Low
Note 1: Low is when VTXC, VTXQ, OR VLO = 0V; high is when VTXC, VTXQ, or VLO = VL.
Note 2: Low is when C/Q or DO < 8V; high is when C/Q or DO >13V.
Table 7. DO Output Programmed by DoBit
LO
DoBit
DoPP
DoN/P
DO CONFIGURATION
High
0
1
X
Push-pull
DO STATE
Low
High
1
1
X
Push-pull
High
High
0
0
0
PNP
Off, DO is high impedance
High
1
0
0
PNP
On, DO is high
High
0
0
1
NPN
On, DO is low
High
1
0
1
NPN
Off, DO is high impedance
Low
X
X
X
See Table 6
See Table 6
X = Don’t care.
LO
DoBit
DoInv
DO
Figure 9. Equivalent DO Logic
�� Maxim Integrated Products 24
MAX14821
IO-Link Device Transceiver
Mode Register [R1, R0] = [1,1]
Bit
D7
D6
D5
D4
D3
D2
D1
D0
Bit Name
RST
WuIntEn
DoFault
C/QFault
UV24
OTemp
UV33En
LDO33Dis
Read/Write
R/W
R/W
R
R
R
R
R
R/W
POR State
0
0
0
0
0
0
0
0
Use the Mode register to reset the MAX14821 and manage the 3.3V LDO. The Mode register has bits that represent the current status of fault conditions. When writing to the Mode register, the contents of the fault indication bits
(bits 2 to 5) do not change.
BIT
NAME
DESCRIPTION
D7
RST
Register Reset. Set RST to 1 to reset all registers to their default power-up state. Then
set RST to 0 for normal operation.
The Status register is cleared and IRQ deasserts (if asserted) when RST = 1. Interrupts
are not generated while RST = 1.
D6
WuIntEn
Wake-Up Interrupt Enable. Set WuIntEn to 1 to enable wake-up interrupt generation.
When WuIntEn is set, the WuInt bit in the Status register is set and IRQ asserts when
a valid wake-up condition is detected. The C/Q driver must be enabled for wake-up
detection. The state of WuIntEn does not affect the WU output. See the Wake-Up
Detection section for more information.
D5
DoFault
DO Fault Status. The DoFault bit is set when a short circuit or voltage fault occurs at
the DO driver output (see the DO Fault Detection section for more information). The
DoFault and DoFaultInt bits are both set when a fault occurs on DO. DoFault is cleared
when the fault is removed.
D4
C/QFault
C/Q Fault Status. The C/QFault bit is set when a short circuit or voltage fault occurs at
the C/Q driver output (see the C/Q Fault Detection section for more information). The
C/QFault and C/QFaultInt bits are both set when a fault occurs on C/Q. C/QFault is
cleared when the fault is removed.
D3
UV24
VCC Undervoltage Condition. Both the UV24 and the UV24Int bits are set when VCC
falls below VCCUVLO. UV24 is cleared when VCC rises above the VCC threshold. V5
must be present for VCC undervoltage monitoring.
D2
OTemp
Temperature Warning. The OTemp bit is set when a high-temperature condition
occurs on the device. Both the OTempInt interrupt in the Status register and the OTemp
bit are set when the junction temperature of the die rises to above +115NC (typ). The
OTemp bit is cleared when the junction temperature falls below +95NC (typ).
D1
UV33En
LDO33 UV Enable. Set the UV33En bit to 1 to assert the UV output when LDO33 voltage falls below the 2.4V (typ) undervoltage-lockout threshold. The UV33En bit does
not affect the UV33Int bit in the Status register; IRQ asserts when VLDO33 falls below
VLDO33UVLO regardless of the state of UV33En.
D0
LDO33Dis
LDO33 Enable/Disable. Set LDO33Dis to 1 to disable the 3.3V linear regulator (LDO33).
�� Maxim Integrated Products 25
MAX14821
IO-Link Device Transceiver
SPI Interface
for the device is 12MHz. The SPI interface complies with
clock polarity CPOL = 0 and clock phase CPHA = 0 (see
Figure 10 and Figure 11).
The device communicates through an SPI-compatible
4-wire serial interface. The interface has three inputs—
clock (SCLK), chip select (CS), and data in (SDI)—and
one output, data out (SDO). The maximum SPI clock rate
The SPI interface is not available when V5 or VL are not
present.
CS
SCLK
SDI
W
0
0
0
0
R1
0
R0
D7
D6
D5
D4
D3
D2
D1
D0
R_ = REGISTER ADDRESS
D_ = DATA BIT
= CLOCK EDGE WHEN LOGIC IS LATCHED
Figure 10. SPI Write Cycle
CS
SCLK
SDI
X
R
0
0
0
0
0
R1
R0
X
D7
SDO
D6
D5
D4
D3
D2
D1
D0
R_ = REGISTER ADDRESS
D_ = DATA BIT
= CLOCK EDGE WHEN LOGIC IS LATCHED
= CLOCK EDGE AT WHICH LOGIC IS WRITTEN
Figure 11. SPI Read Cycle
�� Maxim Integrated Products 26
MAX14821
IO-Link Device Transceiver
Applications Information
UART Interfacing
MICROCONTROLLER
The logic levels of the microcontroller interface I/Os
(TXC, TXQ, TXEN, and RX) are defined by VL.
GPO
TXQ
TX
TXC
RTS
TXEN
RX
Transient Protection
MAX14821
RX
Figure 12. UART Interface
1/2
SDC36C
1μF
LDOIN VP
0.8Ω
VCC
1/2
SDC36C
MAX14821
The device can be interfaced to microcontrollers where
the on-board UART TX output cannot be programmed as
a logic output (GPO). In this case, connect the TX output
of the UART to the TXC input for IO-Link communication
and connect a separate GPO output on the microcontroller to TXQ for standard IO (SIO) mode operation
(Figure 12). As the TXQ and TXC inputs are internally
logically ANDed, the unused input (TXC or TXQ) must be
held high while the other is in operation.
1μF
DO
1/2
SDC36C
C/Q
DI
SDC36C
GND
Figure 13. MAX14821 Operating Circuit with TVS Protection
Inductive load switching, surges, and bursts create high
transient voltages. C/Q, DO, and DI should be protected
against high overvoltage and undervoltage transients.
Positive voltage transients on C/Q, DO, and DI must be
limited to +55V relative to GND and negative voltage
transients must be limited to -55V (relative to VCC) on DO
and C/Q and to -55V (relative to GND) on DI. Figure 12
shows suitable protection using TVS diodes to meet both
the IEC 61000-4-2 ESD and IEC 61000-4-5 surge testing.
Other protection schemes may also be suitable.
To protect against large transients at VCC, insert a
lowpass filter on VCC (see Figure 13 and the Typical
Operating Circuit).
External Power
The device is powered by VCC and the 5V regulator, V5.
VL is a reference voltage input to set the logic levels of
the microcontroller interface. The logic and SPI interface
are operational when V5 and VL are present even if VCC
is not present.
The VP output provides a reverse-polarity-protected voltage one diode drop below VCC and can be used for supplying external circuitry, like power supplies.
Connect LDOIN to V5 to power the V5 input with an
external supply (Figure 14). This configuration disables
operation of the internal 5V regulator and reduces power
consumption.
�� Maxim Integrated Products 27
MAX14821
IO-Link Device Transceiver
EN
IN
MAX15062
5V STEP-DOWN
REGULATOR
LX
GND
FB
3.3V
1μF
0.1μF
10kΩ
VCC
GPIO2
UV
VL
TXQ LDO33 V5 LDOIN VP
0.8Ω
VCC
1μF
SPI
MICROCONTROLLER
GND
IRQ
WU
RX
RX
TX
TXC
RTS
TXEN
GPIO1
LO
DO
MAX14821
L+
1
2
C/Q
DI
4
3
L-
GND
Figure 14. Use an External Supply to Power the MAX14821
Ordering Information
PART
TEMP RANGE
PIN-PACKAGE
MAX14821ETG+
-40°C to +85°C
24 TQFN-EP*
MAX14821EWA+**
-40°C to +85°C
25 WLP
+Denotes a lead(Pb)-free/RoHS-compliant package.
*EP = Exposed pad.
**Future product—contact factory for availability.
Chip Information
PROCESS: BiCMOS
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
OUTLINE
NO.
LAND
PATTERN NO.
24 TQFN-EP
T2444+4
21-0139
90-0022
25 WLP
W252A2+1
21-0191
Application
Note 1891
�� Maxim Integrated Products 28
MAX14821
IO-Link Device Transceiver
Revision History
REVISION
NUMBER
REVISION
DATE
0
8/11
Initial release
12/11
Corrected data line direction for Typical Operating Circuit, removed TOC 14 and
added new TOC 17, corrected DO Fault Detection section, corrected Thermal
Shutdown section, corrected IEC number in Transient Protection section, corrected
Figures 11 and 14
1
DESCRIPTION
PAGES
CHANGED
—
1, 13, 17, 18,
26, 28
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 29
Maxim is a registered trademark of Maxim Integrated Products, Inc.

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MAXIM MAX14821_12