8 x Digital Sensor Interface
FZE 1658G
Features
q
q
q
q
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Input protection against 2000 V burst/500 V surge
pulse according to IEC 801 4/5
Input characteristic according to IEC 65 A, type 2
(24 V DC)
Digital filter
Serial in/out for easy cascading
Low power dissipation
SMD package
P-DSO-24-1
Type
FZE 1658G
Ordering Code
Q67000-A8361
Package
P-DSO-24-1
The FZE 1658G is an integrated interface for digital sensors - i.e. proximity switches - in
industrial automation equipment. The IC has eight integrated highly protected and
failsafe inputs with status LED and a serial synchronous output for direct MC-interfacing.
Semiconductor Group
1
01.97
FZE 1658G
Pin Configuration
(top view)
Semiconductor Group
2
FZE 1658G
Pin Definitions and Functions
Pin
15, 13, 11, 9,
5, 3, 1, 23
16, 14, 12,
10, 6, 4, 2, 24
21
7
22
Symbol Function
I0 - I7
L0 - L7
CT
GND
DGND
Inputs for 24-V signals, in conjunction with
R
V
and
R
EXT
current sink characteristic.
Outputs for the status LEDs; LED lights when H-signal is
present at input.
Pin for connecting the frequency-determining capacitor for
the filter clock; also reset input if CT is connected to DGND
.
Ground for all 24-V signals, substrate.
Ground for all 5-V signals, no internal connection to GND.
Any interruption of GND or DGND with the supply voltage
present may result in destruction of the device.
Supply voltage; undervoltage activates internal reset.
Serial output, open drain.
Extention input for serial cascading with pull-up current
source.
Latch input, edge H-L results in transfer of data from the
digital filters to the output register.
Clock for serial output, positive edge triggered.
8
20
17
18
19
V
S
SO-N
SE-N
LO-N
T
Semiconductor Group
3
FZE 1658G
Functional Description and Application
The Integrated circuit FZE 1658G is used to detect the signal states of eight independent
input lines according to IEC 65A Type 2 (e.g. two-wire proximity switches) with a
common ground (GND). For operation in accordance with IEC 65A, it is necessary for
the device to be wired with resistors rated
R
V
= 820
Ω
and
R
EXT
= 4.4 kΩ with
±
2 %
tolerance and 200 ppm TK. The input device has the following characteristics:
–
–
–
–
–
Minimization of power dissipation due to constant current characteristic
Inputs protected against reverse polarity and transient overvoltages
Status LED output for each input
Digital averaging of the input signals to suppress interference pulses
Serial output of the detected signals (cascadable)
Maximum voltage ratings at inputs D0 ... D7 within test circuit 2.
Voltage Range
DC voltage
Overvoltage 500 ms
Overvoltage 1.3 ms
to VDE 0160
Surge pulse 50
µs
to IEC 801-5,
Z
i
= 2
Ω
Burst pulse 50 ns
to IEC 801-4,
Z
i
= 50
Ω
1)
2)
Notes
full function
non-destructive, no latch-up
full function
non-destructive, no latch-up
full function
non-destructive, no latch-up
1)
– 3 V … + 32 V
– 32 V … + 32 V
– 3 V … + 35 V
– 35 V … + 35 V
– 3 V … + 55 V
±
55
±
0.5 kV
±
2 kV
2)
Non-destructive in temperature range 15
°C ≤
T
A
≤
35
°C.
In temperature range 15
°C ≤
T
A
≤
35
°C:
Data retained if the supply voltage remains within the operating range; without supply voltage
non-destructive.
The rated voltage may be applied to all inputs simultaneously.
The values given in the table may be regarded as guaranteed, but are only checked as
part of a qualification (no 100 % series testing).
Within the application circuit given the same voltage ratings as above apply for the
supply line.
Semiconductor Group
4
FZE 1658G
Circuit Description
In IEC 65A, the following values are specified for 24-VDC input stages of type 2:
Level
1
0
Input Voltage
min. 11 V
max. 11 V
or max. 5 V
Input Current
min. 6 mA
max. 2 mA
The current in the input circuit is determined by the switching element in state “0” and by
characteristics of the input stage in state “1”.
The octal input device FZE 1658G is intended for a configuration comprising two
specified external resistors per channel, as shown in the block diagram. As a result the
power dissipation within the P-DSO-24-1 package is at a minimum.
The voltage dependent current through the external resistor
R
EXT
is compensated by a
negative differential resistance of the current sink across pins E and L, therefore input D
behaves like a constant current sink.
The comparator assigns level 1 or 0 to the voltage present at input E. To improve
interference protection, the comparator is provided with hysteresis and a delay element.
A status LED is connected in series with the input circuit (
R
EXT
and current sink). The
LED drive short-circuits the status LED if the comparator detects “0”. A constant current
sink in parallel with the LED reduces the operating current of the LED, and a voltage
limiter ensures that the input circuit remains operational if the LED is interrupted. The
specified switching thresholds may change if the LED is interrupted.
For each channel a digital filter is provided which samples the comparator signal at a rate
provided by the clock oscillator. The digital filter is designed as a 5-section shift register.
If any four out of 5 sampling values are identical, the output S changes to the
corresponding state.
On a falling edge at input LO-N, the parallel data S0 - S7 are clocked into the output shift
register. The data can be shifted out serially to the output SO-N by the clock signal T,
with a “1” at the input being represented by a L-signal at the output SO-N. The serial
interface of the shift register fits the synchronous interface of the 8051 microcontroller
(see
diagram Serial Data Output Function).
By connecting output SO-N to input SE-
N of the next device, several FZE 1658G can be cascaded (see
Application Circuit).
SO-N is designed as an open-drain output. SE-N has an internal pull-up current source.
Inputs SE-N, T and SO-N have Schmitt trigger characteristics. The device has separate
ground pins for the input circuitry (GND) and for the logic (DGND). If the supply voltage
falls below
V
USR
or CT is connected to DGND, the output shift register will be cleared and
the output SO-N disabled. If the supply voltage is too low, the LED drives will also be
disabled, i.e. the LED lights as soon as current flows in the input circuit.
Semiconductor Group
5
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