PSoC® Creator™ Component Data Sheet Programmable Gain Amplifier (PGA) 1.60 Features • Gain steps from 1 to 50 • High input impedance • Selectable input reference • Adjustable power settings General Description The PGA implements an opamp-based, non-inverting amplifier with user-programmable gain. This amplifier has high input impedance, wide bandwidth, and selectable input voltage reference. It is derived from the SC/CT block. The gain can be between 1 (0 dB) and 50 (+34 dB). The gain may be selected via configuration or changed at run-time using the provided API. The maximum bandwidth is limited by the gainbandwidth product of the opamp and is reduced as the gain is increased. The input of the PGA operates from rail to rail, but the maximum input swing (difference between Vin and Vref) is limited to Vdda/Gain. The output of the PGA is class A, and is rail to rail for sufficiently high load resistance. The PGA is used when an input signal has insufficient amplitude. A PGA may be placed in front of a comparator, ADC, or mixer to increase the amplitude of the signal to these components. The PGA can be used as a unity gain amplifier to buffer the inputs of lower impedance blocks, including Mixers or inverting PGAs. A unity gain PGA can also be used to buffer the output of a VDAC or reference. Input/Output Connections This section describes the various input and output connections for the PGA. An asterisk (*) in the list of I/Os indicates that the I/O may be hidden on the symbol under the conditions listed in the description of that I/O. Vin – Analog Vin is the input signal terminal. Cypress Semiconductor Corporation • 198 Champion Court • San Jose, CA 95134-1709 • 408-943-2600 Document Number: 001-65706 Rev. ** Revised December 13, 2010 Programmable Gain Amplifier (PGA) PSoC® Creator™ Component Data Sheet Vref – Analog * Vref is the input terminal for a reference signal. The reference input can be connected to an external (to the component) reference or internal (to the component) Vss (ground). When the reference is connected externally the routing resistance is added to the internal resistors slightly decreasing the gain and increasing the gain tolerance. Vout – Analog Vout is the output voltage signal terminal. Vout is a function of (Vin - Vref) times the specified Gain: Vout = Vref + (Vin - Vref) * Gain Parameters and Setup Drag a PGA component onto your design and double-click it to open the Configure dialog. Gain This sets the initial gain of the PGA. The gain may be selected from the following set of allowed values: 1 (default), 2, 4, 8, 16, 24, 32, 48, and 50. Page 2 of 13 Document Number: 001-65706 Rev. ** PSoC® Creator™ Component Data Sheet Programmable Gain Amplifier (PGA) Power This sets the initial drive power of the PGA. The power determines the speed with which the PGA reacts to changes in the input signal. There are four power settings; Minimum, Low, Medium (default), and High. Minimum Power setting results in the slowest response time and a High Power setting results in the fastest response time. Vref_Input This parameter is used to select the input voltage reference. The options include: • "Internal Vss" – Uses a ground signal internal to the component • "External" (default) – Signal on the Vref terminal provides the amplifier reference. The symbol displayed in PSoC Creator changes depending on the reference input selected. Figure 1 PGA Configurations Placement There are no placement specific options. Resources The PGA uses one SC/CT block. Details on this block can be found in the applicable device data sheet and Technical Reference Manual (TRM). These documents are available on the Cypress web site. API Memory (Bytes) Digital Blocks Analog Blocks Datapaths Macro cells Status Registers Control Registers Counter7 Flash RAM Pins (per External I/O) 1 SC/CT fixed block N/A N/A N/A N/A N/A 381 20 3 Document Number: 001-65706 Rev. ** Page 3 of 13 Programmable Gain Amplifier (PGA) PSoC® Creator™ Component Data Sheet Application Programming Interface Application Programming Interface (API) routines allow you to configure the component using software. The following table lists and describes the interface to each function. The subsequent sections cover each function in more detail. By default, PSoC Creator assigns the instance name "PGA_1" to the first instance of a component in a given design. You can rename it to any unique value that follows the syntactic rules for identifiers. The instance name becomes the prefix of every global function name, variable, and constant symbol. For readability, the instance name used in the following table is "PGA". Function Description void PGA_Start(void) Start the PGA. void PGA_Stop(void) Power down the PGA. void PGA_SetGain(uint8 gain) Set gain to pre-defined constants. void PGA_SetPower(uint8 power) Set drive power to one of four settings. void PGA_Sleep(void) Stops and saves the user configurations. void PGA_Wakeup(void) Restores and enables the user configurations. void PGA_Init(void) Initializes or restores default PGA configuration. void PGA_Enable(void) Enables the PGA. void PGA_SaveConfig(void) Empty function. Provided for future usage. void PGA_RestoreConfig(void) Empty function. Provided for future usage. Global Variables Variable PGA_initVar Page 4 of 13 Description Indicates whether the PGA has been initialized. The variable is initialized to 0 and set to 1 the first time PGA_Start() is called. This allows the component to restart without reinitialization after the first call to the PGA_Start() routine. If reinitialization of the component is required, then the PGA_Init() function can be called before the PGA_Start() or PGA_Enable() function. Document Number: 001-65706 Rev. ** PSoC® Creator™ Component Data Sheet Programmable Gain Amplifier (PGA) void PGA_Start(void) Description: This is the preferred method to begin component operation. Turns on the amplifier with the power and gain based on the settings provided during the configuration or the current values after a PGA_Stop() has been called. Parameters: None Return Value: None Side Effects: None void PGA_Stop(void) Description: Turn off PGA and enable its lowest power state. Note This API is not recommended for use on PSoC 3 ES2 and PSoC 5 ES1 silicon. These devices have a defect that causes connections to several analog resources to be unreliable when not powered. The unreliability manifests itself in silent failures (e.g. unpredictably bad results from analog components) when the component utilizing that resource is stopped. It is recommended that all analog components in a design should be powered up (by calling the PGA_Start() APIs) at all times. Do not call the PGA_Stop() APIs. Parameters: None Return Value: None Side Effects: None. Does not affect power or gain settings void PGA_SetPower(uint8 power) Description: Sets the drive power to one of four settings; minimum, low, medium, or high. Parameters: (uint8) power: See the following table for valid power settings. Power Setting Notes PGA_MINPOWER Minimum active power and slowest reaction time. PGA_LOWPOWER Low power and speed. PGA_MEDPOWER Medium power and speed. PGA_HIGHPOWER Highest active power and fastest reaction time. Return Value: None Side Effects: None Document Number: 001-65706 Rev. ** Page 5 of 13 Programmable Gain Amplifier (PGA) PSoC® Creator™ Component Data Sheet void PGA_SetGain(uint8 gain) Description: Set the amplifier gain to a value between 1 and 50. Parameters: uint8 gain: See table below for valid gain settings. Gain Setting Notes PGA_GAIN_01 Gain = 1 PGA_GAIN_02 Gain = 2 PGA_GAIN_04 Gain = 4 PGA_GAIN_08 Gain = 8 PGA_GAIN_16 Gain = 16 PGA_GAIN_24 Gain = 24 PGA_GAIN_32 Gain = 32 PGA_GAIN_48 Gain = 48 PGA_GAIN_50 Gain = 50 Return Value: None Side Effects: None void PGA_Sleep(void) Description: This is the preferred API to prepare the component for sleep. The PGA_Sleep() API saves the current component state. Then it calls the PGA_Stop() function and calls PGA_SaveConfig() to save the hardware configuration. Call the PGA_Sleep() function before calling the CyPmSleep() or the CyPmHibernate() function. Refer to the PSoC Creator System Reference Guide for more information about power management functions. Parameters: None Return Value: None Side Effects: None void PGA_Wakeup(void) Description: This is the preferred API to restore the component to the state when PGA_Sleep() was called. The PGA_Wakeup() function calls the PGA_RestoreConfig() function to restore the configuration. If the component was enabled before the PGA_Sleep() function was called, the PGA_Wakeup() function will also re-enable the component. Parameters: None Return Value: None Side Effects: Calling the PGA_Wakeup() function without first calling the PGA_Sleep() or PGA_SaveConfig() function may produce unexpected behavior. Page 6 of 13 Document Number: 001-65706 Rev. ** PSoC® Creator™ Component Data Sheet Programmable Gain Amplifier (PGA) void PGA_Init(void) Description: Initializes or restores the component according to the customizer Configure dialog settings. It is not necessary to call PGA_Init() because the PGA_Start() API calls this function and is the preferred method to begin component operation. Parameters: None Return Value: None Side Effects: All registers will be set to values according to the customizer Configure dialog. void PGA_Enable(void) Description: Activates the hardware and begins component operation. It is not necessary to call PGA_Enable() because the PGA_Start() API calls this function, which is the preferred method to begin component operation. Parameters: None Return Value: None Side Effects: None void PGA_SaveConfig(void) Description: Empty function. Provided for future usage. Parameters: None Return Value: None Side Effects: None void PGA_RestoreConfig(void) Description: Empty function. Provided for future usage. Parameters: None Return Value: None Side Effects: None Sample Firmware Source Code PSoC Creator provides numerous example projects that include schematics and example code in the Find Example Project dialog. For component-specific examples, open the dialog from the Component Catalog or an instance of the component in a schematic. For general examples, open the dialog from the Start Page or File menu. As needed, use the Filter Options in the dialog to narrow the list of projects available to select. Refer to the "Find Example Project" topic in the PSoC Creator Help for more information. Document Number: 001-65706 Rev. ** Page 7 of 13 Programmable Gain Amplifier (PGA) PSoC® Creator™ Component Data Sheet Functional Description The PGA is constructed from a generic SC/CT block. Details on this block can be found in the applicable device data sheet and TRM, available on the Cypress web site. The gain is selected by adjusting two resistors, Ra and Rb. (see functional schematic, Figure 3). Ra may be set to either 20K or 40K ohms. Rb is set between 20K and 1000K ohms to generate the gain values selectable in either the parameter dialog or the SetGain function. The block has a programmable capacitor in parallel with the feedback resistor, Rb. The value of the capacitor is configured for each gain selection to achieve guaranteed stability. Reassigning Rb values without also selecting the appropriate feedback capacitor value may result in PGA instability. The user is strongly advised to use the provided APIs for gain changes. Figure 2 PGA Schematic Vin Vout Vref Ra Rb The bandwidth of the PGA is determined by gain and power setting. Because of compensation capacitor and stability requirements, the bandwidth is somewhat reduced from the absolute maximum expected from the opamp's open loop gain-bandwidth. Registers The PGA component configuration is implemented in registers SC[0..3]_CR0, SC[0..3]_CR1 and SC[0..3]_CR2. These can be accessed in user code by reference to the instantiated component name, e.g., PGA_1_CR0_REG. The register contents can be reviewed in the PSoC Creator component debug window. Refer to the applicable TRM, available on the Cypress web site, for a detailed description of each register. The following registers are displayed in the PGA component debug window. Register: PGA_1_CR0_REG Name: Switched Capacitor Control Register 0 Description: Register bits 3:1 configure the switch capacitor block operating mode. This field is set to 110b for the PGA component. Page 8 of 13 Document Number: 001-65706 Rev. ** PSoC® Creator™ Component Data Sheet Programmable Gain Amplifier (PGA) Register: PGA_1_CR1_REG Name: Switched Capacitor Control Register 1 Description: Register fields configure drive mode, compensation capacitor values, and gain setting of the switch capacitor block. Register: PGA_1_CR2_REG Name: Switched Capacitor Control Register 2 Description: Register fields configure the input impedance, feedback impedance and the reference ground selection for the switch capacitor block. Register: PGA_1_PM_ACT_CFG_REG Name: Active Power Mode Configuration Register 9 Description: Register bits 3:0 enable power to each of the four switch capacitor blocks. DC and AC Electrical Characteristics The following values are based on characterization data. Specifications are valid for -40°C £ TA £ 85°C and TJ £ 100°C except where noted. Unless otherwise specified in the tables below, all Typical values are for TA = 25°C, Vdda = 5.0V, Power = High, output referenced to analog ground, Vssa . 5.0V/3.3V DC Electrical Characteristics Parameter Description Conditions Min Typ Max Units Input Vos Input Offset Voltage All Power Modes (High, Med, Low, Min) na 3.5 10 mV TCVos Temp. coeff. input offset voltage, absolute value All Power Modes (High, Med, Low, Min) na 6.0 12.3 uV/°C Input capacitance Positive gain, non-inverting input, not including pin and routing capacitance na 2.0 na pF Gain accuracy, deviation from nominal G=1, Vref internally connected to Vss 0.01 0.15 +/-% G=2, Vref internally connected to Vss 0.1 1.0 Ge4 G=4, Vref internally connected to Vss 0.5 1.35 Ge8 G=8, Vref internally connected to Vss 0.6 1.6 Ge16 G=16, Vref internally connected to Vss 0.7 2.5 Ge32 G=32, Vref internally connected to Vss 0.85 5.0 Cin Ge1 Ge2 Document Number: 001-65706 Rev. ** Page 9 of 13 Programmable Gain Amplifier (PGA) Parameter PSoC® Creator™ Component Data Sheet Description Conditions Ge50 Min G=50, Vref internally connected to Vss Typ Max 2.1 5.0 1.2 2.5 G=2, Vref internally connected to Vss 8.6 20 Gd4 G=4, Vref internally connected to Vss 13 29 Gd8 G=8, Vref internally connected to Vss 15 35 Gd16 G=16, Vref internally connected to Vss 18 40 Gd32 G=32, Vref internally connected to Vss 38 75 Gd50 G=50, Vref internally connected to Vss 167 400 Gd1 Gain change vs temp Gd2 G=1, Vref internally connected to Vss Vout_range Output swing Gain = 1, Rload = 100k to Vdda/2, Difference from Vdda or Vssa Idda Operating current Vdda=1.71 V, P=Low Vdda=5.0 V, P=High na Units ppm/°C 150 mV 700 1000 uA 1100 1350 uA Figures Histogram Input Offset Voltage 18 16 Typical Operating Current vs Temp, Power = Minimum 1200 Occurance 1100 Idda uA 14 12 1000 10 900 8 800 6 4 700 2 600 Page 10 of 13 Vos mV 6.0 4.0 2.0 0.0 -2.0 -4.0 -6.0 0 500 -50 5.5V 3.3V 2.7V 1.71V 0 50 deg C 100 150 Document Number: 001-65706 Rev. ** PSoC® Creator™ Component Data Sheet Programmable Gain Amplifier (PGA) Typical Operating Current vs Temp, Power = Low Typical Operating Current vs Temp, Power = High 1200 1200 1100 1100 Idda uA 1000 1000 900 900 5.5V 3.3V 2.7V 1.71V 800 700 800 Idda uA 700 600 600 500 -50 5.5V 3.3V 2.7V 1.71V 0 50 deg C 100 150 500 -50 0 50 deg C 100 150 5.0V/3.3V AC Electrical Characteristics Parameter Description Conditions Min Typ Max Units GBW_H Gain Bandwidth Product, P=High Gain=1, Vdda=5.0 V, 25 C 7.0 9.0 na MHz SR_G1 Slew Rate 20 - 80%, Gain=1, P=High 3.0 4.8 na V/us SR_G16 20 - 80%, Gain=16, P=High 0.5 0.87 na V/us SR_G50 20 - 80%, Gain=50, P=High 0.25 0.84 na V/us f = 100 kHz 48 f=100 kHz, P=High na PSRR_AC Power supply rejection ratio Vn Document Number: 001-65706 Rev. ** dB 42 na nV/rtHz Page 11 of 13 Programmable Gain Amplifier (PGA) PSoC® Creator™ Component Data Sheet Figures Typical Gain vs Frequency, Power=High Voltage noise, Vdda = 5.0V, Power=High 1000 40 20 nV/rtHz G=50 G=32 G=16 G=8 G=4 G=2 G=1 dB 30 100 10 0 -10 1 10 100 kHz 1000 10000 10 0.01 0.1 1 kHz 10 100 1000 Bandwidth vs. Temperature, at Different Gain Settings, Power = High Data collection is currently in progress. Page 12 of 13 Document Number: 001-65706 Rev. ** PSoC® Creator™ Component Data Sheet Programmable Gain Amplifier (PGA) Component Changes This section lists the major changes in the component from the previous version. Version 1.60 Description of Changes Reason for Changes / Impact Removed VDDA parameter from component customizer VDDA setting in the component is redundant and unnecessary for multiple components. The parameter was removed and the component queries the global setting for minimum VDDA in the DWR and automatically enables the pump when necessary. Configuration window created to include Frequency response graphs a better ease of use GUI. Previous configuration window did not provide enough information for ease of use. SetGain constants corrected in the header file The constants provided for the SetGain API had incorrect values. These have been corrected. Added characterization data to datasheet Minor datasheet edits and updates 1.50 Added Sleep/Wakeup and Init/Enable APIs. To support low power modes, as well as to provide common interfaces to separate control of initialization and enabling of most components. Removed Gain setting of 25. The gain of 25 was too close to other values and therefore offered no value. Updated the symbol image and Configure dialog. These were updated to comply with corporate standards. Changed the names of the registers Updated to comply with coding guidelines. by adding "_REG." Added specification table and graphic placeholders Data to be provided when characterization is complete. © Cypress Semiconductor Corporation, 2009-2010. The information contained herein is subject to change without notice. Cypress Semiconductor Corporation assumes no responsibility for the use of any circuitry other than circuitry embodied in a Cypress product. Nor does it convey or imply any license under patent or other rights. Cypress products are not warranted nor intended to be used for medical, life support, life saving, critical control or safety applications, unless pursuant to an express written agreement with Cypress. Furthermore, Cypress does not authorize its products for use as critical components in life-support systems where a malfunction or failure may reasonably be expected to result in significant injury to the user. The inclusion of Cypress products in life-support systems application implies that the manufacturer assumes all risk of such use and in doing so indemnifies Cypress against all charges. PSoC® is a registered trademark, and PSoC Creator™ and Programmable System-on-Chip™ are trademarks of Cypress Semiconductor Corp. All other trademarks or registered trademarks referenced herein are property of the respective corporations. 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Disclaimer: CYPRESS MAKES NO WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, WITH REGARD TO THIS MATERIAL, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. Cypress reserves the right to make changes without further notice to the materials described herein. Cypress does not assume any liability arising out of the application or use of any product or circuit described herein. Cypress does not authorize its products for use as critical components in lifesupport systems where a malfunction or failure may reasonably be expected to result in significant injury to the user. The inclusion of Cypress’ product in a life-support systems application implies that the manufacturer assumes all risk of such use and in doing so indemnifies Cypress against all charges. Use may be limited by and subject to the applicable Cypress software license agreement. Document Number: 001-65706 Rev. ** Page 13 of 13