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零件编号 | WM8200-12 | ||
描述 | 40MSPS ADC | ||
制造商 | Wolfson Microelectronics | ||
LOGO | |||
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WM8200-10/12
40MSPS ADC with PGA
DESCRIPTION
The WM8200 is a CMOS high speed, low power, pipeline
analogue-to-digital converter (ADC) with 10 or 12-bit output
options. It also has an on-chip programmable gain amplifier
(PGA), dc clamp circuit and internal voltage references.
Conversion is controlled by a single clock input.
The device has a high bandwidth differential sample and hold
input, which gives excellent common-mode noise immunity
and low distortion. Alternatively, it can be driven in single
ended fashion with an optional voltage clamp for dc
restoration that can take its reference from an on-chip 10-bit
DAC.
The WM8200 provides internal reference voltages for setting
the ADC full-scale range without the requirement for external
circuitry. However, it can also accept external references for
applications where shared or high-precision references are
required.
A 3-wire serial interface is used to control the device and a
10 or 12-bit parallel interface is to read ADC conversion data.
ADC data can be output in unsigned binary or two’s
complement format.
The WM8200 operates with a single 3V supply and is
supplied in a 28-lead QFN package.
BLOCK DIAGRAM
CLAMP
FEATURES
• 10 or 12-bit resolution ADC
• 40MSPS conversion rate
• Programmable Gain Amplifier (PGA)
• Adjustable internal voltage references
• Built in clamp function (dc restore) with 10-bit DAC
• Wide Input Bandwidth - 900MHz
• Unsigned Binary or Two’s complement output format
• Programmable via 3-wire serial MPU interface
• Single 3V supply operation
• Low power - 100mW typical at 3.0V supplies
• Powerdown mode to <0.1mW typical
• 28 lead QFN package
APPLICATIONS
• Digital Still Cameras
• Composite Video Digitisation
• Digital Copiers
• Digital Video Cameras
CLAMP
AMPLIFIER
CLAMP
LEVEL
DAC
CONTROL
REGISTERS
SCLK
SDIN
CSB
AINP
AINN
S/H
PGA
AADDCC
CCOoRreE
OUTPUT
BUFFERS
DO[9:0] WM8200-10
or
DO[11:0] WM8200-12
REFSENSE
VREF
MODE
ON-CHIP
REFERENCE
GENERATOR
AVDD AGND
REFB REFT
TIMING
CONTROL
WM8200
CLK
DVDD
DGND
WOLFSON MICROELECTRONICS LTD
www.wolfsonmicro.com
Product Preview March 2002, Rev 1.22
Copyright 2002 Wolfson Microelectronics Ltd.
www.DataSheet4U.com
WM8200
Product Preview
PROGRAMMABLE-GAIN AMPLIFIER
VP is amplified by the PGA and fed into the ADC as a differential voltage VQ = VQ+ - VQ-
VQ = Gain × VP = Gain × (VINP − VINN )
The PGA gain defaults to 1.0 at power-up, but can be programmed from 0.5 to 4.0 in steps of 0.5.
ANALOGUE-TO-DIGITAL CONVERTER
Regardless of the reference configuration, VQ is digitised against ADC Reference voltages REFT and
REFB, full scale values of VQ being given by:
VQFS
=
REFT
− REFB
2
and zero scale by
VQZS
=
− REFT
− REFB
2
Attempts to convert VQ voltages outside the range of VQZS to VQFS are signalled to the application by
driving the OVR output pin high when the conversion result is output. If VQ is less than VQZS, the ADC
output code is 0. If VQ is greater than VQFS, the output code is 1023.
SIGNAL CHAIN SUMMARY
Combining the above equations to find the input voltages [AINP – AINN] that correspond to the limits
of the ADCs valid input range gives:
(REFB − REFT )
(2 ×Gain)
≤
[
AINP
−
AINN ]
≤
(REFT − REFB)
(2 ×Gain)
Therefore the input signal span is given by:
AINP − AINN = REFT − REFB
Gain
In order to match the ADC input range to the input signal amplitude, REFT and REFB should be set
such that:
REFT − REFB = ( AINP − AINN ) × Gain
ADC REFERENCE MODES
The WM8200 references REFT and REFB can be driven from external (off-chip) sources or from the
internal reference generation/buffer circuit. The mode of operation is selected by the voltage applied
to the MODE pin. These are summarised and explained in Table 2.
MODE
PIN
AGND
AVDD
MODE
Note that the internally generated ADC references are intended solely for WM8200 internal use and
REFT and REFB must not be used as voltage references for any other device in the application.
FUNCTION
COMMENTS
Full external
Top/Bottom
REFT = external
REFB = external
REFTF = AVDD + (REFTS − REFBS)
2
REFBF = AVDD − (REFTS − REFBS)
2
On-chip reference generator and reference buffer are
not used.
On-chip reference generator is not used. Reference
buffer centers external reference voltages around
AVDD/2.
Table 2 WM8200 Reference Generation Modes
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PP Rev 1.22 March 2002
8
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WM8200
IMPORTANT NOTICE
Product Preview
Wolfson Microelectronics Ltd (WM) reserve the right to make changes to their products or to discontinue any product or
service without notice, and advise customers to obtain the latest version of relevant information to verify, before placing
orders, that information being relied on is current. All products are sold subject to the WM terms and conditions of sale
supplied at the time of order acknowledgement, including those pertaining to warranty, patent infringement, and limitation
of liability.
WM warrants performance of its products to the specifications applicable at the time of sale in accordance with WM’s
standard warranty. Testing and other quality control techniques are utilised to the extent WM deems necessary to support
this warranty. Specific testing of all parameters of each device is not necessarily performed, except those mandated by
government requirements.
In order to minimise risks associated with customer applications, adequate design and operating safeguards must be used
by the customer to minimise inherent or procedural hazards.
WM assumes no liability for applications assistance or customer product design. WM does not warrant or represent that
any license, either express or implied, is granted under any patent right, copyright, mask work right, or other intellectual
property right of WM covering or relating to any combination, machine, or process in which such products or services might
be or are used. WM’s publication of information regarding any third party’s products or services does not constitute WM’s
approval, license, warranty or endorsement thereof.
Reproduction of information from the WM web site or datasheets is permissible only if reproduction is without alteration and
is accompanied by all associated warranties, conditions, limitations and notices. Representation or reproduction of this
information with alteration voids all warranties provided for an associated WM product or service, is an unfair and deceptive
business practice, and WM is not responsible nor liable for any such use.
Resale of WM’s products or services with statements different from or beyond the parameters stated by WM for that
product or service voids all express and any implied warranties for the associated WM product or service, is an unfair and
deceptive business practice, and WM is not responsible nor liable for any such use.
ADDRESS:
Wolfson Microelectronics plc
Westfield House
26 Westfield Road
Edinburgh
EH11 2QW
Tel :: +44 (0)131 272 7000
Fax :: +44 (0)131 272 7001
Email :: [email protected]
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PP Rev 1.22 March 2002
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页数 | 16 页 | ||
下载 | [ WM8200-12.PDF 数据手册 ] |
零件编号 | 描述 | 制造商 |
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