CY8C38_11 CYPRESS [Cypress Semiconductor], CY8C38_11 Datasheet - Page 57

• Manufacturer Part Number: CY8C38_11
• Manufacturer: CYPRESS [Cypress Semiconductor]

Figure 8-7. Opamp
The opamp is uncommitted and can be configured as a gain
stage or voltage follower, or output buffer on external or internal
signals.
See
can all be connected to the internal global signals and monitored
with an ADC, or comparator. The configurations are
implemented with switches between the signals and GPIO pins.
Figure 8-8. Opamp Configurations
The opamp has three speed modes, slow, medium, and fast. The
slow mode consumes the least amount of quiescent power and
the fast mode consumes the most power. The inputs are able to
swing rail-to-rail. The output swing is capable of rail-to-rail
operation at low current output, within 50 mV of the rails. When
driving high current loads (about 25 mA) the output voltage may
only get within 500 mV of the rails.
Document Number: 001-11729 Rev. *R
Internal Bus
Global Bus
Global Bus
Analog
Analog
Analog
Figure
VREF
GPIO
GPIO
To Internal Signals
8-8. In any configuration, the input and output signals
Vin
Vp
Vn
c) Internal Uncommitted
b) External Uncommitted
a) Voltage Follower
Opamp
Opamp
Opamp
Opamp
Opamp
Opamp
=
Analog Switch
GPIO Pin
Vout to GPIO
Vp to GPIO
Vn to GPIO
Vout to Pin
Vout to Pin
GPIO
8.5 Programmable SC/CT Blocks
The CY8C38 family of devices contains up to four switched
capacitor/continuous time (SC/CT) blocks in a device. Each
switched capacitor/continuous time block is built around a single
rail-to-rail high bandwidth opamp.
Switched capacitor is a circuit design technique that uses
capacitors plus switches instead of resistors to create analog
functions. These circuits work by moving charge between
capacitors by opening and closing different switches.
Nonoverlapping in phase clock signals control the switches, so
that not all switches are ON simultaneously.
The PSoC Creator tool offers a user friendly interface, which
allows you to easily program the SC/CT blocks. Switch control
and clock phase control configuration is done by PSoC Creator
so users only need to determine the application use parameters
such as gain, amplifier polarity, V
The same opamps and block interfaces are also connectable to
an array of resistors which allows the construction of a variety of
continuous time functions.
The opamp and resistor array is programmable to perform
various analog functions including
8.5.1 Naked Opamp
The Naked Opamp presents both inputs and the output for
connection to internal or external signals. The opamp has a unity
gain bandwidth greater than 6.0 MHz and output drive current up
to 650 µA. This is sufficient for buffering internal signals (such as
DAC outputs) and driving external loads greater than 7.5 kohms.
8.5.2 Unity Gain
The Unity Gain buffer is a Naked Opamp with the output directly
connected to the inverting input for a gain of 1.00. It has a –3 dB
bandwidth greater than 6.0 MHz.
8.5.3 PGA
The PGA amplifies an external or internal signal. The PGA can
be configured to operate in inverting mode or noninverting mode.
The PGA function may be configured for both positive and
negative gains as high as 50 and 49 respectively. The gain is
adjusted by changing the values of R1 and R2 as illustrated in
Figure
and possible resistor settings for the PGA. The gain is switched
from inverting and non inverting by changing the shared select
value of the both the input muxes. The bandwidth for each gain
case is listed in
Naked operational amplifier – Continuous mode
Unity-gain buffer – Continuous mode
PGA – Continuous mode
Transimpedance amplifier (TIA) – Continuous mode
Up/down mixer – Continuous mode
Sample and hold mixer (NRZ S/H) – Switched cap mode
First order analog to digital modulator – Switched cap mode
8-9. The schematic in
Table
PSoC
8-3.
Figure 8-9
®
REF
3: CY8C38 Family
connection, and so on.
shows the configuration
Data Sheet
Page 57 of 129
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