Document
DISCRETE SEMICONDUCTORS
DATA SHEET
handbook, halfpage
M3D282
KMI15/1 Integrated rotational speed sensor
Product specification Supersedes data of 2000 Jun 26
2000 Sep 05
Philips Semiconductors
Integrated rotational speed sensor
Product specification
KMI15/1
FEATURES
• Digital current output signal • Zero speed capability • Wide air gap • Wide temperature range • Insensitive to vibration • EMC resistant.
PINNING
PIN DESCRIPTION 1 VCC 2 V−
DESCRIPTION
The KMI15/1 sensor detects rotational speed of ferrous gear wheels and reference marks(1). The sensor consists of a magnetoresistive sensor element, a signal conditioning integrated circuit in bipolar technology and a magnetized ferrite magnet. The frequency of the digital current output signal is proportional to the rotational speed of a gear wheel.
handbook, halfpage
CAUTION
Do not press two or more products together against their magnetic forces.
(1) The sensor contains a customized integrated circuit. Usage in hydraulic brake systems and in systems with active brake control is forbidden. For all other applications, higher
temperature versions of up to 150 °C are available on
request.
12
MBH781
Fig.1 Simplified outline (SOT453B).
QUICK REFERENCE DATA
SYMBOL
VCC ICC (low) ICC (high) d ft Tamb
PARAMETER DC supply voltage current output signal low current output signal high sensing distance operating tooth frequency ambient operating temperature
MIN.
− − − 0 to 2.5 0 −40
TYP.
12 7 14 0 to 2.9 − −
MAX.
− − − − 25 000 +85
UNIT V mA mA mm Hz °C
2000 Sep 05
2
Philips Semiconductors
Integrated rotational speed sensor
Product specification
KMI15/1
LIMITING VALUES In accordance with Absolute Maximum Rating System (IEC 60134).
SYMBOL
PARAMETER
CONDITIONS
VCC Tstg Tamb Tsld
DC supply voltage storage temperature
Tamb = −40 to +85 °C; RL = 115 Ω
ambient operating temperature
soldering temperature
t ≤ 10 s
output short-circuit duration to GND
MIN. MAX.
−0.5 +16 −40 +150 −40 +85 − 260 continuous
UNIT
V °C °C °C
CHARACTERISTICS Tamb = 25 °C; VCC = 12 V; d = 2.1 mm; ft = 2 kHz; test circuit: see Fig.7; RL = 115 Ω; sensor positioning: see Fig.15; gear wheel: module 2 mm; material 1.0715; unless otherwise specified.
SYMBOL
PARAMETER
CONDITIONS
MIN. TYP. MAX.
ICC (low) ICC (high) tr tf td
current output signal low current output signal high output signal rise time output signal fall time switching delay time
see Figs 6 and 8
5.6
see Figs 6 and 8
11.2
CL = 100 pF; see Fig.9; 10 to 90% value − CL = 100 pF; see Fig.9; 10 to 90% value −
between stimulation pulse (generated by a coil) and output signal
−
7 14 0.5 0.7 1
8.4 16.8 − − −
ft operating tooth frequency for both rotation directions
d sensing distance see Fig.15 and note 1
δ duty cycle
see Fig.6
0 − 25000 0 to 2.5 0 to 2.9 − 30 50 70
UNIT mA mA µs µs µs
Hz mm %
Note 1. High rotational speeds of wheels reduce the sensing distance due to eddy current effects (see Fig.17).
2000 Sep 05
3
Philips Semiconductors
Integrated rotational speed sensor
Product specification
KMI15/1
FUNCTIONAL DESCRIPTION
The KMI15/1 sensor is sensitive to the motion of ferrous gear wheels or reference marks. The functional principle is shown in Fig.3. Due to the effect of flux bending, the different directions of magnetic field lines in the magnetoresistive sensor element will cause an electrical signal. Because of the chosen sensor orientation and the direction of ferrite magnetization, the KMI15/1 is sensitive to movement in the ‘y’ direction in front of the sensor only (see Fig.2).
The magnetoresistive sensor element signal is amplified, temperature compensated and passed to a Schmitt trigger in the conditioning integrated circuit (Figs 4 and 5). The digital output signal level (see Fig.6) is independent of the sensing distance within the measuring range (Fig.14). A (2-wire) output current enables safe transfer of the sensor signal to the detecting circuit (see Fig.7). The integrated circuit housing is separated from the sensor element housing to optimize the sensor behaviour at high temperatures.
handbook, halfpage x y
magnet with direction of magnetization
x z
sensor IC
MBH778
Fig.2 Component detail of the KMI15/1.
handbook, full pagewigdethar wheel z magnet
sensor y
(a)
2000 Sep 05
magnetic field lines
direction of
motion
(b) (c)
Fig.3 Functional principle. 4
MRA957
(d)
Philips Semiconductors
Integrated rotational speed sensor
Product specification
KMI15/1
handbook, full pagewidth
VOLTAGE CONTROL
CONSTANT CURRENT SOURCE
V CC
SENSOR
AMPLIFIER
SCHMITT TRIGGER
SWITCHABLE CURRENT SOURCE
V
MRA958
Fig.4 Block diagram.
handbook, full pagewidth
switchable current source
sensor
EMC FILTER
preamplifier
Schmitttrigger
constant current source
VCC
power supply
Vref GAP
V
MRA959
2000 Sep 05
Fig.5 Simplified circuit diagram. 5
Philips Semiconductors
Integrated rotational speed sensor
Product specification
KMI15/1
handbook, halfpage
I CC
14 mA
T
7 mA
tp
MRA960
t
SENSOR.