MAX9621AUB+ [MAXIM]
Analog Circuit, 1 Func, BICMOS, PDSO10, 3 X 5 MM, ROHS COMPLIANT, MO-187BA, UMAX-10;
| 型号： | MAX9621AUB+ |
| 厂家： | 
MAXIM INTEGRATED PRODUCTS |
| 描述： | Analog Circuit, 1 Func, BICMOS, PDSO10, 3 X 5 MM, ROHS COMPLIANT, MO-187BA, UMAX-10 信息通信管理 光电二极管 |
| 文件： | 总15页 (文件大小：1635K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
EVALUATION KIT AVAILABLE
MAX9621
Dual, 2-Wire Hall-Effect Sensor Interface with
Analog and Digital Outputs
General Description
Features
S Provides Supply Current and Interfaces to Two
The MAX9621 is a continuation of the Maxim family of
Hall-effect sensor interfaces that already includes the
MAX9921. The MAX9621 provides a single-chip solution
to interface two 2-wire Hall-effect sensors to low-voltage
microprocessors (FP) through either a digital output for
Hall-effect switches or an analog output for linear infor-
mation or both.
2-Wire Hall-Effect Sensors
S 5.5V to 18V Operating Voltage Range
S Protects Hall Sensors Against Up to 60V Supply
Transients
S Low-Power Shutdown for Power Saving
S Filtered Digital Outputs
The MAX9621 protects the Hall sensors from supply
transients up to 60V at the BAT supply. Normal operating
supply voltage ranges from 5.5V to 18V. If the BAT sup-
ply rises above 18V, the MAX9621 shuts off the current to
the Hall sensors. When a short-to-ground fault condition
is detected, the current to the Hall input is shut off and
the condition is indicated at the analog output by a zero-
current level and a high digital output.
S Analog Output Mirrors the Hall Sensor Current
S Hall Inputs Protected from Short to Ground
S Hall Sensor Blanking Following Power-Up and
Restart from Shutdown and Short to Ground
S Operates with ±±V Ground Shift Between the Hall
Sensor and the MAX9621
S ±2kV Human Body Model ESD and ±200V Machine
Model ESD at All Pins
The MAX9621 provides a minimum of 50Fs blanking
time following Hall sensor power-up or restart. The open-
drain digital outputs are compatible with logic levels up
to 5.5V.
S ±mm x 5mm, 10-Pin µMAX Package
Ordering Information
PART
TEMP RANGE
-40NC to +125NC
-40NC to +125NC
PIN-PACKAGE
10 FMAX
The MAX9621 is available in a 3mm x 5mm, 10-pin
MAX9621AUB+T
MAX9621AUB/V+
M
FMAX package and is rated for operation in the -40NC
10 FMAX
to +125NC temperature range.
+Denotes a lead(Pb)-free/RoHS-compliant package.
T = Tape and reel.
/V denotes an automotive qualified part.
Applications
Window Lifters
Seat Movers
Functional Diagram
Electric Sunroofs
BAT
Seatbelt Buckles
REF
REFERENCE
ISET
Door Power Locks
Ignition Key
BAT
SLEEP-MODE
CONTROL
SLEEP
10kI
Steering Column
Speed Sensing
AOUT1
DOUT1
IN1
FILTER
REF
BAT
INPUT
SHORT
MAX9621
DETECTION
Typical Application Circuit appears at end of data sheet.
AOUT2
DOUT2
IN2
FILTER
REF
GND
µMAX is a registered trademark of Maxim Integrated Products, Inc.
For pricing, delivery, and ordering information, please contact Maxim Direct
at 1-888-629-4642, or visit Maxim’s website at www.maximintegrated.com.
19-5024; Rev 1; 9/11
MAX9621
Dual, 2-Wire Hall-Effect Sensor Interface with
Analog and Digital Outputs
ABSOLUTE MAXIMUM RATINGS
BAT to GND...........................................................-0.3V to +60V
ISET to BAT ..........................................................-2.0V to +0.3V
Continuous Power Dissipation for a Single-Layer Board
(T = +70NC)
A
IN1, IN2 to GND................ -3V to lower of +60V or (V
AOUT1, DOUT1, AOUT2, DOUT2,
+ 1V)
10-Pin µMAX (derate 5.6mW/NC) above +70NC........444.4mW
Continuous Power Dissipation for a Multilayer Board
BAT
SLEEP to GND .....................................................-0.3V to +6V
Short-Circuit Duration
AOUT1, DOUT1, AOUT2, DOUT2 to GND
or to 5.5V (individually).......................................Continuous
Current In to IN1, IN2.................................................... 100mA
Current In to Any Other Pin............................................. 20mA
(T = +70NC)
A
10-Pin µMAX (derate 8.8mW/NC) above +70NC........707.3mW
Operating Temperature Range........................ -40NC to +125NC
Junction Temperature .....................................................+150NC
Storage Temperature Range............................ -65NC to +160NC
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.
DC ELECTRICAL CHARACTERISTICS
(V
BAT
= 13.6V, V
= 5V, IN1 = IN2 = no connection, R
= 61.9kI to BAT, R = 10kI at DOUT1 and DOUT2, R = 5kI to
SET PU L
SLEEP
GND at AOUT1 and AOUT2, unless otherwise noted, T = -40NC to +125NC. Typical values are at T = +25NC.) (Note 1)
A
A
PARAMETER
GENERAL
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Guaranteed by functional test of I , I ,
IH IL
BAT Supply Range
BAT Supply Current
V
5.5
18
V
BAT
and G
EI
I
Normal mode
1
mA
BAT
I
1
10
FA
V
= 0V
SD
SLEEP
V
= 5.5V, at IN1 and IN2,
= -14mA
BAT
0.59
1.26
1.86
I
IN
Hall Input Voltage Dropout
ESD Protection
V
DO
V
V
V
= 5.5V, at IN1 and IN2,
= -20mA
BAT
0.86
I
IN
Machine Model
±200
Human Body Model
±2000
INPUT THRESHOLDS FOR DOUT1, DOUT2 SWITCHING
R
R
R
R
= 95.3kI
= 52.3kI
= 95.3kI
= 52.3kI
-7.7
-14
Input Current for Output High
(Note 2)
SET
SET
SET
SET
I
mA
mA
%
IH
-5
-9
Input Current for Output Low
(Note 2)
I
IL
Input Current Hysteresis for
High/Low Detection
Peak-to-peak as percent of average high/
low threshold (Note 2)
I
8
IN_HYS
High threshold
Low threshold
0.02
0.02
Channel-to-Channel Input
Threshold Variation
mA
A short to GND is not a sustained
condition, Hall input reverts to -50FA when
detected (Note 2)
Short-Circuit Current Limit
I
-20
mA
SC
AOUT1, AOUT2 ANALOG OUTPUTS
Current Gain for AOUT1 and
AOUT2 Outputs
G
-18mA PI P-2mA
0.05
0.2
mA/mA
%
I
IN
Current Gain Error for AOUT1
and AOUT2 Outputs
G
EI
I
= -5mA, -14mA
IN
±1.7
2
Maxim Integrated
MAX9621
Dual, 2-Wire Hall-Effect Sensor Interface with
Analog and Digital Outputs
DC ELECTRICAL CHARACTERISTICS (continued)
(V
BAT
= 13.6V, V
= 5V, IN1 = IN2 = no connection, R = 61.9kI to BAT, R = 10kI at DOUT1 and DOUT2, R = 5kI to
SET PU L
SLEEP
GND at AOUT1 and AOUT2, unless otherwise noted, T = -40NC to +125NC. Typical values are at T = +25NC.) (Note 1)
A
A
PARAMETER
SYMBOL
CONDITIONS
Inferred from measurements at
= -5mA, -14mA
MIN
TYP
MAX
UNITS
Input Referred Current Offset
I
-120
+120
FA
OS
I
IN
V
= 5.5V,
BAT
I
I
= -14mA
= -20mA
0.85
1.6
IN
AOUT_ Dropout Voltage
for 5% current
reduction
V
1.09
500
1.75
IN
AOUT_ Output Impedance
MI
LOGIC I/O (DOUT1, DOUT2)
Output-Voltage Low DOUT1,
DOUT2
V
I
Sink current = 1mA
0.4
V
OL
Three-State Output Current
DOUT1, DOUT2
FA
V
= 0V, 0V PV
P5V
OZ
SLEEP
DOUT_
±1
SLEEP
Input-Voltage High
Input-Voltage Low
V
2.0
50
V
V
IH
V
0.8
IL
Input Resistance to GND
AC TIMING CHARACTERISTICS
R
100
40
kI
IN
Shutdown Delay from SLEEP
Low to IN_ Shutoff
I
= -14mA to GND, time from SLEEP low
IH
t
t
33
76
46
Fs
Fs
SHDN
to IN_ drop 500mV, C = 20pF
L
I
IH
= -14mA to GND, time from
IN_, Blanking Time at Hall
Sensor Power-Up
t
V
= 500mV until DOUT_ high, C =
89
103
BL
IN_
L
20pF (Notes 2, 3)
IN_, Current Ramp Rate After
Turn-On
IN_ = GND (Note 2)
3.6
5
6.7
16
mA/Fs
Fs
RAMP
Delay from IN_ to DOUT_ (Filter
Delay)
From I to I or from I to I ,
IH IL IL IH
C = 20pF, Figure 1 (Note 2)
t
10.8
13.5
DEL
L
Delay Difference Between
Rising and Falling Edges of
Both Channels
C
= 0.01FF, I = -11.5mA
IH
HALL-BYPASS
t
1
Fs
DM
and I = -7.5mA, C = 20pF
IL
L
Delay Difference Between
Channels
C
= 0.01FF, I = -11.5mA
HALL-BYPASS IH
t
500
39
ns
CC
and I = -7.5mA, C = 20pF
IL
L
Maximum Frequency on Hall
Inputs
C
= 0.01FF, I = -11.5mA
HALL-BYPASS IH
f
34
kHz
MAX
and I = -7.5mA, C = 20pF (Note 2)
IL
L
Maximum Analog Output
Current During Short-to-GND
Fault
I
-1.4
mA
MAO
IN_ Pulse Length Rejected by
Filter to DOUT_
P
Figure 2 (Note 2)
7.8
11.5
14.6
Fs
R
Note 1: All DC specifications are 100% production tested at T = +25°C. AC specifications are guaranteed by design at T
=
A
A
+25°C.
Note 2: Parameters that change with the value of the R
resistor: I , I , I
, I , t , t
, t
, f
, and P .
SET
IH IL IN_HYS SC BL RAMP DEL MAX R
Note ±: Following power-up or startup from sleep mode, the start of the blanking period is delayed 20Fs.
Maxim Integrated
3
MAX9621
Dual, 2-Wire Hall-Effect Sensor Interface with
Analog and Digital Outputs
Timing Diagrams
APPROXIMATELY 100mA
HALL SENSOR
SHORT CIRCUIT
APPROXIMATELY 100mA
OPEN
14mA
5mA/µs
IN1
7mA
0mA
APPROXIMATELY 1.4mA
RESTART
HALL SENSOR OPEN
0.7mA
AOUT1
DOUT1
5mA/µs
0.35mA
0mA
t
DEL
t
DEL
5V
0V
Figure 1. Timing Diagram
P
R
P
R
14mA
IN_
7mA
0mA
t
DEL
t
DEL
5V
0V
DOUT_
Figure 2. Hall Input Pulse Rejection
4
Maxim Integrated
MAX9621
Dual, 2-Wire Hall-Effect Sensor Interface with
Analog and Digital Outputs
Typical Operating Characteristics
(V
BAT
= 13.6V, R
= 61.9kI, R = 5kI to GND at AOUT_, V
= 5V, T = +25NC, unless otherwise noted.)
SET
L
SLEEP A
BAT SUPPLY CURRENT
vs. V IN OPERATING MODE
BAT SUPPLY CURRENT
vs. V IN OPERATING MODE
BAT SUPPLY CURRENT
vs. V IN OPERATING MODE
BAT
= -40NC
BAT
= +25NC
BAT
0.9
0.8
0.7
0.6
0.5
0.4
0.9
0.8
0.7
0.6
0.5
0.4
0.9
0.8
0.7
0.6
0.5
0.4
T
A
T
A
T = +125NC
A
19.0
19.5
20.0
20.5
21.0
19.0
19.5
20.0
20.5
21.0
19.0
19.5
20.0
20.5
21.0
BAT VOLTAGE (V)
BAT VOLTAGE (V)
BAT VOLTAGE (V)
BAT SUPPLY CURRENT
vs. V IN OPERATING MODE
BAT SUPPLY CURRENT
vs. V IN OPERATING MODE
BAT SUPPLY CURRENT
vs. V IN OPERATING MODE
BAT
BAT
BAT
1.0
0.8
0.6
0.4
0.2
1.0
0.8
0.6
0.4
0.2
1.0
0.8
0.6
0.4
0.2
T
A
= -40NC
T
A
= +25NC
TA = +125NC
0
10
20
30
40
50
60
0
10
20
30
40
50
60
0
10
20
30
40
50
60
BAT VOLTAGE (V)
BAT VOLTAGE (V)
BAT VOLTAGE (V)
BAT SUPPLY CURRENT
vs. V IN SHUTDOWN MODE
HALL INPUT CURRENT THRESHOLDS
FOR HIGH/LOW vs. TEMPERATURE
HALL INPUT CURRENT
THRESHOLDS vs. V
BAT
BAT
200
180
160
140
120
100
80
10.4
10.2
10.0
9.8
10.50
10.25
10.00
9.75
9.50
9.25
9.00
8.75
8.50
T = +125°C
A
LOW TO HIGH
LOW TO HIGH
9.6
9.4
60
9.2
HIGH TO LOW
10.5
40
T = +25°C AND -40°C
A
9.0
HIGH TO LOW
20
0
8.8
0
20
40
60
80
-40 -25 -10
5
20 35 50 65 80 95 110 125
TEMPERATURE (°C)
5.5
8.0
13.0
15.5
18.0
BAT VOLTAGE (V)
BAT VOLTAGE (V)
Maxim Integrated
5
MAX9621
Dual, 2-Wire Hall-Effect Sensor Interface with
Analog and Digital Outputs
Typical Operating Characteristics (continued)
(V
BAT
= 13.6V, R
= 61.9kI, R = 5kI to GND at AOUT_, V
= 5V, T = +25NC, unless otherwise noted.)
SET
L
SLEEP A
INPUT BLANKING TIME AT RESTART
FROM SLEEP MODE (OR POWER-UP)
vs. TEMPERATURE
HALL INPUT CURRENT THRESHOLDS
vs. ISET RESISTOR
IN-CURRENT RAMP RATE AFTER
TURN-ON vs. TEMPERATURE
16
14
12
10
8
100
95
90
85
80
75
70
65
60
10
9
8
7
LOW TO HIGH
HIGH TO LOW
6
5
4
6
3
4
2
50
60
70
80
90
100
-40 -25 -10
5
20 35 50 65 80 95 110 125
TEMPERATURE (°C)
-40 -25 -10
5
20 35 50 65 80 95 110 125
TEMPERATURE (°C)
RESISTANCE (kI)
DELAY FROM IN_ TO DOUT_ (FILTER DELAY)
vs. TEMPERATURE
20
DELAY DIFFERENCE BETWEEN CHANNELS
vs. TEMPERATURE
MAXIMUM FREQUENCY ON
HALL INPUTS vs. TEMPERATURE
900
700
500
300
100
-100
60
50
40
30
20
10
15
10
5
IN1
IN2
0
-50 -25
0
25
50
75 100 125
-50 -25
0
25
50
75 100 125
-50 -25
0
25
50
75 100 125
TEMPERATURE (NC)
TEMPERATURE (NC)
TEMPERATURE (NC)
IN_ PULSE LENGTH REJECTED BY FILTER
TO DOUT_ vs. TEMPERATURE
INPUT DROPOUT VOLTAGE
vs. TEMPERATURE
INPUT DROPOUT VOLTAGE
vs. V
BAT
20
18
16
14
12
10
8
1.15
1.05
0.95
0.85
0.75
0.65
0.55
0.45
0.35
0.25
1.15
1.05
0.95
0.85
0.75
0.65
0.55
0.45
0.35
0.25
I
= -14mA
IN1
V
= 5.5V
= -14mA
BAT
I
IN1
T
A
= +125°C
NEGATIVE PULSE
POSITIVE PULSE
T
= +25°C
A
6
T
A
= -40°C
4
2
0
18.00
5.50
8.00
10.50
13.00
(V)
15.50
-50 -25
0
25
50
75 100 125
-45 -25 -10
5
20 35 50 65 80 95 110 125
TEMPERATURE (°C)
TEMPERATURE (NC)
V
BAT
6
Maxim Integrated
MAX9621
Dual, 2-Wire Hall-Effect Sensor Interface with
Analog and Digital Outputs
Typical Operating Characteristics (continued)
(V
BAT
= 13.6V, R
= 61.9kI, R = 5kI to GND at AOUT_, V
= 5V, T = +25NC, unless otherwise noted.)
SET
L
SLEEP
A
CURRENT GAIN vs. SUPPLY VOLTAGE
CURRENT GAIN vs. TEMPERATURE
0.07
0.06
0.05
0.04
0.03
0.07
0.06
0.05
0.04
0.03
5.50
-50 -25
0
25
50
75 100 125
TEMPERATURE (NC)
SUPPLY VOLTAGE (V)
REENERGIZING OF THE HALL INPUT
RESPONSE TO SHORT TO GROUND
FROM OPEN-CIRCUIT CONDITION
MAX9621 toc21
MAX9621 toc22
V
V
IN1
AOUT1
V
IN1
V
DOUT1
I
IN1
I
IN1
V
AOUT1
400ns/div
100µs/div
STARTUP OF IN_/DOUT_
STARTUP OF IN_/AOUT_
FROM SHUTDOWN
FROM SHUTDOWN
MAX9621 toc24
MAX9621 toc23
V
SLEEP
V
IN1
V
V
SLEEP
IN1
I
I
IN1
IN1
V
AOUT1
V
DOUT1
20µs/div
10µs/div
Maxim Integrated
7
MAX9621
Dual, 2-Wire Hall-Effect Sensor Interface with
Analog and Digital Outputs
Pin Configuration
TOP VIEW
+
BAT
ISET
IN1
1
2
3
4
5
10
9
SLEEP
AOUT1
DOUT1
AOUT2
DOUT2
MAX9621
8
IN2
7
GND
6
µMAX
Pin Description
PIN
NAME
FUNCTION
Battery Power Supply. Connect to the positive supply through an external reverse-polarity diode.
Bypassed to GND with a 0.1FF capacitor.
1
BAT
Current Setting Input. Place a 1% resistor (R ) between BAT and ISET to set the desired input current
SET
threshold range for the DOUT_ outputs. See the Typical Operating Characteristics section for the correct
value of R for the desired range. Make no other connections to this pin. All routing must have low
parasitic capacitance. See the Input Current Thresholds and Short to Ground section.
2
3
ISET
IN1
SET
Hall-Effect Sensor Input 1. Supplies current to the Hall sensor and monitors the current level drawn to
determine the high/low state of the sensor. Bypass to GND with a 0.01FF capacitor. Connect an unused
input to BAT pin.
Hall-Effect Sensor Input 2. Supplies current to the Hall sensor and monitors the current level drawn to
determine the high/low state of the sensor. Bypass to GND with a 0.01FF capacitor. Connect an unused
input to BAT pin.
4
5
IN2
GND
Ground
8
Maxim Integrated
MAX9621
Dual, 2-Wire Hall-Effect Sensor Interface with
Analog and Digital Outputs
Pin Description (continued)
PIN
NAME
FUNCTION
Open-Drain Output. Signal translated from Hall sensor 2. DOUT2 is high when the current flowing out of
6
DOUT2 IN2 exceeds the input current threshold high, and is low when less than the input current threshold low.
See Table 1 for output response to operating conditions.
Analog Current Output. Mirrors the current to the corresponding Hall sensor at IN2. When IN2 has been
AOUT2 shut down due to a short to GND a current of zero is supplied to AOUT2. See Table 1 for output response
to operating conditions. To obtain a voltage output, connect a resistor from AOUT_ to ground.
7
8
9
Open-Drain Output. Signal translated from Hall sensor 1. DOUT1 is high when the current flowing out of
DOUT1 IN1 exceeds the input current threshold high, and is low when less than the input current threshold low.
See Table 1 for output response to operating conditions.
Analog Current Output. Mirrors the current to the corresponding Hall sensor at IN1. When IN1 has been
AOUT1 shut down due to a short to GND a current of zero is supplied to AOUT1. See Table 1 for output response
to operating conditions. To obtain a voltage output, connect a resistor from AOUT_ to ground.
Sleep Mode Input. The part is placed in sleep mode when the SLEEP input is low for more than 40Fs.
If the SLEEP input is low for less than 20Fs and then goes high, the part restarts any Hall input that has
been shut off due to a detected short to GND. Any Hall input that is operational is not affected when
10
SLEEP
SLEEP is cycled low for less than 20Fs. There is an internal 100kI pulldown resistance to GND.
outputs low when the current flowing out of IN1 or IN2,
respectively, is lower than the low-input current threshold.
DOUT1 and DOUT2 provide a time domain output filter
for robust noise immunity. See Figure 2.
Detailed Description
The MAX9621, an interface between two 2-wire Hall-
effect sensors and a low-voltage microprocessor, sup-
plies and monitors current through IN1 and IN2 to two
Hall sensors.
The analog outputs (AOUT1 and AOUT2) mirror the cur-
rent flowing out to the corresponding inputs IN1 and IN2
with a nominal gain of 0.05mA/mA.
The MAX9621 complements Maxim’s existing family of
Hall-effect sensor interfaces that includes the MAX9921.
Hall Sensor Protection
from Supply Transients
The MAX9621 protects the hall sensors from supply
transients by shutting off current at IN1 and IN2 when
the BAT voltage is 18V. The digital outputs go low and
The MAX9621 provides two independent channels with
two outputs for each channel, a digital output, and an
analog output. The digital outputs (DOUT1 and DOUT2)
are open-drain and indicate a logic level that corresponds
to the Hall sensor status. DOUT1 or DOUT2 outputs high
when the current out of IN1 or IN2, respectively, exceeds
the high-input current threshold. DOUT1 or DOUT2
analog outputs have zero output current. When V
BAT
returns to the proper operating range, both inputs restart
following a blanking cycle.
Maxim Integrated
9
MAX9621
Dual, 2-Wire Hall-Effect Sensor Interface with
Analog and Digital Outputs
tripping into a short-to-ground latched state. During
the short-to-ground fault, DOUT1 and DOUT2 are high
impedance (pulled high by the pullup resistors), while
AOUT1 and AOUT2 are set to zero-output current.
Table 1. AOUT_/DOUT_ Truth Table
CONDITION
IN_ Short to GND
AOUT_
DOUT_
High-Z
Low*
0
0
0
0
IN_ Short to BAT or IN_ Open
Manual Method for Reenergizing Hall
Sensor and Means for Diagnosing an
Intermittent Hall Sensor Connection
SLEEP Low
High-Z
Low*
V
> 18V
BAT
*If IN_ is already shorted to BAT or open during power-up,
DOUT_ goes to high-Z until IN_ is loaded.
Figure 3 shows the behavior of the MAX9621 when a
Hall input is open. Figure 4 shows the behavior of the
MAX9621 when the open input is reconnected to a Hall
sensor. Figures 3 and 4 demonstrate how a short-to-
ground Hall input can be reset. Resetting a short-to-
ground Hall input involves three steps:
Hall Input Short-to-Battery Condition
The MAX9621 interprets a short to battery when the volt-
age at IN1 or IN2 is higher than V
- 100mV. The digi-
BAT
tal outputs go low and the analog outputs are set to zero
output current. If IN1 or IN2 is more than 1V above V
it back-drives current into BAT. The MAX9621 restarts
the Hall inputs when the Hall input is loaded again.
1) Relieve the short to ground at the Hall sensor.
,
BAT
2) Disconnect the Hall input from the Hall sensor (open-
input fault condition).
3) Reconnect the Hall input to the Hall sensor.
Hall Input Short to Ground
The Hall input short-to-ground fault is effectively a
latched condition if the input remains loaded by the Hall
switch. The current required to power the Hall switch is
shut off and only a 50µA pullup current remains. The Hall
input can be manually reenergized or it can be reener-
gized by the µP. A 10µs to 20µs negative pulse at SLEEP
restarts with a blanking cycle any Hall input that has
been shut down due to the short-to-ground condition.
During startup or restart, it is possible for a Hall input
to charge up an external capacitance of 0.02µF without
The MAX9621 restarts the Hall input with a blanking
cycle. If the Hall input is disconnected from the Hall
sensor for 10ms, it allows the Hall input to be pulled up
by the 50FA pullup current to register the open-input
fault condition. Reconnecting the Hall input to the Hall
sensor restarts the Hall input with a blanking cycle. This
provides a manual means of reenergizing a Hall input
without having to resort to the FP to restart it. This also
demonstrates the behavior of an intermittent connection
to a Hall sensor.
14V
V
- 25mV
BAT
HALL INPUT
SHORT-TO-
GROUND FAULT
5mV/ms
V
IN_
HALL INPUT
OPEN-CIRCUIT
FAULT
0V
TIME
TIME
HALL INPUT
DISCONNECTED
FROM SENSOR
50µA
I
IN_
0A
Figure 3. Hall Input Ramps to Open-Circuit Fault When a Short to Ground Is Relieved
10
Maxim Integrated
MAX9621
Dual, 2-Wire Hall-Effect Sensor Interface with
Analog and Digital Outputs
V
BAT
- 25mV
14V
V
IN_
8V
V
- 500mV
BAT
0V
11.5mA
TIME
TIME
I
IN_
5mA/µs
HALL INPUT RECONNECTED
TO HALL SENSOR
0A
Figure 4. Hall Input Reenergized When Open Input Is Reconnected to Hall Sensor
1
Sleep Mode Input (SLEEP)
The MAX9621 features an active-low SLEEP input. Pull
SLEEP low for more than 40Fs to put the device into
sleep mode for power saving. In sleep mode, the DOUT1
and DOUT2 outputs are high impedance and are pulled
high by pullup resistors. AOUT1 and AOUT2 are set to
zero-output current.
I = I
+
I < 0
(
)
0
R×m
I is the mean of the threshold current limits, R is
the value of the R resistance in kΩ, the constant
SET
I
= 0.03717mA, and the constant m = -0.001668
0
(1/(kΩ x mA)).
The following equation is useful for finding the value of
Hall Input Restart
When an input has been shut down due to a short to
ground, cycle SLEEP for 10Fs to 20Fs to restart the input.
If the other input is operational it is not affected. The
restart happens on the rising edge of SLEEP.
R
limits:
resistance given a mean of the threshold current
SET
Y = Y + m × I I < 0
(
)
0
1
Y
R =
Input Current Thresholds and
Short to Ground
The input current high and low thresholds that determine
the logic level of the digital outputs are adjusted by
-5
Y = 6.2013 x 10 units of (1/kΩ)
0
To compute the typical input current thresholds from the
mean input current, it is necessary to obtain the hyster-
esis. The following equation finds the hysteresis given
the mean threshold current, I:
changing the R
value. When the R
value changes,
SET
SET
the following parameters change as well: I
, I
,
IN_HYS SC
t
, t
, t
, f
and P .
BL RAMP DEL MAX, R
H = H + k x I (I < 0)
0
I , I , I
, I , t
, and f
are inversely pro-
IH IL IN_HYS SC RAMP
MAX
where H = -0.033463 in mA, and k = -0.08414 in mA/mA.
0
portional to R
and decrease as R
increases. This
SET
SET
inverse relationship is linear. For example, a 10% change in
Input current threshold high = I - H/2, input current
threshold low = I + H/2.
(1/R ) results in a 10% change in current parameters.
SET
Conversely, time and delay parameters are linear and
directly proportional to R , and a 10% change in R
results in an 10% change in time parameters.
Application Information
SET
SET
Use of Digital and Analog Outputs
The digital output can be used to provide the FP with an
interrupt signal that can represent a Hall sensor change
of status. DOUT1 and DOUT2 provide a time domain
output filter for robust noise immunity. See Figure 2.
The analog output can be connected to an ADC with an
appropriate load resistor, and can be used to perform
custom diagnostics.
The difference between the maximum and minimum
threshold current limits is the min/max limit spread, which
is greater than the threshold hysteresis. The min/max
spread and the hysteresis both change by the same per-
centage as the mean of the threshold current limits. The
following equation is useful for finding the mean of the
threshold current limits given a value of R
resistance:
SET
Maxim Integrated
11
MAX9621
Dual, 2-Wire Hall-Effect Sensor Interface with
Analog and Digital Outputs
R
MAX9621
V
IN_
CC
X
Figure 5. 3-Wire Hall-Effect Switches Configured as 2-Wire
Table 2. A Partial List of Compatible Hall Switches
PART NO.
MANUFACTURER
WEBSITE
COMMENTS
2-wire
HAL573-6
Micronas
www.micronas.com
www.micronas.com
www.micronas.com
www.allegromicro.com
HAL556/560/566
HAL579/581/584
A1140/1/2/3
Micronas
2-wire
Micronas
2-wire
Allegro
2-wire
3-wire, optimized for 2-wire
use without added resistor
A3161
Allegro
www.allegromicro.com
www.infineon.com
TLE4941/C
Infineon
2-wire
sensor ground, the ground of the MAX9621 and FP. This
ground-shift immunity eliminates the need for a ground-
connection wire, allowing a single-wire interface to the
Hall sensor.
Sleep Mode
Sleep mode can be used in applications that do not
continuously require the polling of the Hall sensors. In
such cases, the FP can enable the MAX9621 for a short
time, check the sensor status, and then put the MAX9621
back to sleep. A blanking period follows upon exiting
sleep mode.
Hall-Effect Sensor Selection
The MAX9621 is optimized for use with 2-wire Hall-effect
switches or with 3-wire Hall-effect switches connected
as 2-wire (Figure 5). When using a 3-wire Hall sensor the
resistor R is chosen so that the current drawn by the Hall
sensor crosses the MAX9621 current threshold when
the magnetic threshold of the Hall sensor is exceeded.
A partial list of Hall switches that can be used with the
MAX9621 is given in Table 2.
Remote Ground
The MAX9621 targets applications with 2-wire Hall-effect
sensors. 2-wire sensors have connections for supply and
ground. The output level is signaled by means of modula-
tion of the current drawn by the Hall sensor from its supply.
The two threshold currents for high/low are generally in the
range of 5mA to 14mA. Thus, the interfacing of a 2-wire
sensor is not simply a matter of detecting two voltage
thresholds, but requires a coarse current-sense function.
Input Current Threshold Precision
To get the best input current threshold precision, it is rec-
ommended that the R
resistor be directly connected
SET
Because of the high-side current-sense structure of the
MAX9621, the device is immune to shifts between the
to the BAT pin. A true Kelvin type connection is best.
12
Maxim Integrated
Typical Application Circuit
1.8V TO 5.5V
0.1µF
BATTERY: 5.5V TO 18V
OPERATING,
60V WITHSTAND
R
R
PU
10kI
PU
10kI
R
SET
BAT
ISET
REF
REFERENCE
SLEEP
SLEEP-MODE
CONTROL
BAT
100kI
AOUT1
DOUT1
ADC
5kI
FILTER
IN1
REF
N
S
0.01µF
MICROPROCESSOR
BAT
INPUT
SHORT
DETECTION
MAX9621
REMOTE
GROUND
AOUT2
DOUT2
ADC
5kI
IN2
N
S
0.01µF
FILTER
REF
REMOTE
GROUND
GND
MAX9621
Dual, 2-Wire Hall-Effect Sensor Interface with
Analog and Digital Outputs
Package Information
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 TYPE
PACKAGE CODE
OUTLINE NO.
21-0061
LAND PATTERN NO.
90-0330
10 FMAX
U10+2
α
α
14
Maxim Integrated
MAX9621
Dual, 2-Wire Hall-Effect Sensor Interface with
Analog and Digital Outputs
Revision History
REVISION
NUMBER
REVISION
DATE
PAGES
CHANGED
DESCRIPTION
0
1
11/09
9/11
Initial release
Added automotive qualified part
—
1
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 160 Rio Robles, San Jose, CA 95134 USA 1-408-601-1000
15
©
2011 Maxim Integrated
Maxim Integrated and the Maxim Integrated logo are trademarks of Maxim Integrated Products, Inc.
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