uzz9000 NXP Semiconductors, uzz9000 Datasheet - Page 9

• Manufacturer Part Number: uzz9000
• Description: Sensor Conditioning Electronics
• Manufacturer: NXP Semiconductors

Philips Semiconductors
Table 4 Programming of trim modes
Reset
In addition to the external reset pin (pin 6), the UZZ9001
provides an internal power-up/ power-down reset logic
which continuously monitors the supply voltage. When the
supply voltage increases and reaches a safe level, reset
becomes inactive and the device starts initialization. When
the supply voltage exceeds the safe voltage level, the
device is reset immediately. This internal reset logic can be
over-ridden by the external pin RES (pin 6) in all modes
and at any time. The reset pin RES (pin 6) is active when
in the high position. It is internally pulled to ground and
therefore need not be connected if the function is not
required.
Diagnostic
The UZZ9000 provides powerful diagnostics features that
allow the user to recognize certain failures of the device or
system. A failure will occur when the output voltage V
either rises above or falls below the normal operation
range. Either one of the diagnostic areas is reached during
any of the following conditions
1. Short circuit between V
2. Short circuit between V
3. Disconnection of V
4. Disconnection of GND when the load is pulled up.
5. Invalid input signal from the sensor, e.g. Magnet Lost.
The internal pull-up and pull-down resistors in the output
buffer block ensure that V
power supplies when the other supply is disconnected so
V
output load. If the external load is a pull-down resistor, then
2000 Nov 27
enter trim mode for sensor input channel 1
enter trim mode for sensor input channel 2
leave trim mode for either input channel
OUT
Sensor Conditioning Electronic
This failure is assumed when the offset corrected input
signal of sensor 1 and sensor 2 is below 15 mV.
reaches the diagnostic region even when there is no
MODE
DD
OUT
when the load is pulled down.
OUT
OUT
will be pulled to one of the
and GND (R < 1 ).
and V
DD
(R < 1 ).
OUT
1
0
0
0
9
the device enters into the diagnostic area if V
disconnected, but not if V
the load is a pull-up resistor, then the device will enter the
diagnostic area if V
disconnected. It is not necessary to connect an output load
to the UZZ9000. After recovering from short circuit to
ground or supply voltage, the chip returns undamaged to
the normal operation mode. There is no time limitation
regarding short circuit of V
Measurement dynamics
The UZZ9000 includes an on-chip RC Oscillator that
generates the clock for the whole device. Consequently,
no external clock supply is required for the measurement
system. The nominal clock frequency of the on-chip
oscillator is 4 MHz at room temperature. It varies with
temperature change. At 40 C the clock frequency may
decrease to 2.3 MHz. At higher temperatures however, a
frequency up to 5.7 MHz may be reached. This influences
the dynamics of measurements. From an application point
of view, two different effects have to be distinguished: The
system delay, which means how long it takes until a
changed input signal is recognized at the output, and the
measurement update rate. The system delay is mainly
caused by the settling time of the low pass decimation
filter, which depends on the maximum frequency content
(shape) of the input signals and the clock frequency. The
following maximum values can be expected for the entire
system delay. The measurement update rate, however, is
directly related to the oscillator frequency. At room
temperature, a new value is available every 0.26 ms.
When taking the entire temperature range into account,
update rates between 0.45 and 0.18 ms are possible. (see
Table 5).
2
0
0
0
STATUS BITS
SS
is disconnected, but not if V
3
0
1
0
SS
OUT
is disconnected. Similarly, if
.
4
1
0
0
Product specification
UZZ9000
DD
is
DD
5
0
0
0
is