WOLFSON WM8200

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WM8200-10/12
40MSPS ADC with PGA
DESCRIPTION
FEATURES
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.
•
•
•
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
The WM8200 operates with a single 3V supply and is
supplied in a 28-lead QFN package.
BLOCK DIAGRAM
CLAMP
CLAMP
LEVEL
DAC
CLAMP
AMPLIFIER
AINP
S/H
PGA
AINN
REFSENSE
VREF
MODE
ADC
ADC
CORE
Core
ON-CHIP
REFERENCE
GENERATOR
CONTROL
REGISTERS
SCLK
SDIN
CSB
OUTPUT
BUFFERS
DO[9:0] WM8200-10
or
DO[11:0] WM8200-12
TIMING
CONTROL
CLK
DVDD
DGND
WM8200
AVDD
AGND
WOLFSON MICROELECTRONICS LTD
www.wolfsonmicro.com
REFB REFT
Product Preview March 2002, Rev 1.22
Copyright 2002 Wolfson Microelectronics Ltd.
WM8200
Product Preview
VREF
AVDD
AGND
DVDD
DO0
DO1
DO2
VREF
AVDD
AGND
DVDD
NC
NC
DO0
PIN CONFIGURATION
28 27 26 25 24 23 22
28 27 26 25 24 23 22
DO1 1
21 AINP
DO3 1
21 AINP
DO2 2
20 AINN
DO4 2
20 AINN
19 REFB
DO5 3
DO3 3
WM8200-10
19 REFB
WM8200-12
18 MODE
16 CLAMP
DO8 6
16 CLAMP
DO7 7
15 REFSENSE
DO9 7
15 REFSENSE
8
9
10
11 12
13 14
CSB
13 14
SDIN
DO9
11 12
CLK
DO8
10
SDIN
9
CLK
8
DGND
DO6 6
SCLK
17 REFT
DO11
DO7 5
DO10
17 REFT
CSB
DO5 5
DGND
DO6 4
SCLK
18 MODE
DO4 4
ORDERING INFORMATION
DEVICE
TEMP. RANGE
PACKAGE
WM8200-10IFL
-40 to +85oC
28-lead QFN
WM8200-12IFL
-40 to +85oC
28-lead QFN
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PIN DESCRIPTION
PIN
NAME
TYPE
DESCRIPTION
1
DO1
DO3
Digital Output
Digital output bit
2
DO2
DO4
Digital Output
Digital output bit
3
DO3
DO5
Digital Output
Digital output bit
4
DO4
DO6
Digital Output
Digital output bit
5
DO5
DO7
Digital Output
Digital output bit
6
DO6
DO8
Digital Output
Digital output bit
7
DO7
DO9
Digital Output
Digital output bit
8
DO8
DO10
Digital Output
Digital output bit
9
DO9
DO11
Digital Output
Digital output bit (MSB)
10
SCLK
Digital Input
11
DGND
Ground
12
CLK
Analogue Input
13
CSB
Digital Input
14
SDIN
Digital Input
15
REFSENSE
Analogue Input
16
CLAMP
Digital Input
17
REFT
Analogue Input/Output
18
MODE
Analogue Input
19
REFB
Analogue Input/Output
20
AINN
Analogue Input
21
AINP
Analogue Input
22
VREF
Analogue Input/Output
3-Wire Control Interface Clock Input
Negative Digital Supply
Clock input
3-Wire Control Interface Chip Select
3-Wire Control Interface Data Input
VREF feedback/configuration control
High to enable clamp mode, low to disable clamp mode
Top ADC reference voltage
High (MODE=AVDD) to enable internal ADC references.
Low (MODE=AVSS) to enable use of external ADC references applied to
REFT and REFB.
Bottom ADC reference voltage
Positive analogue input
Negative analogue Input
Internal/external reference voltage
23
AVDD
Supply
Positive Analogue Supply
24
AGND
Ground
Negative Analogue Supply
25
DVDD
Supply
Positive Digital Supply
26
NC
DO0
Digital Output
Not internally connected (10-bit option)/
Digital output bit (LSB for 12-bit option only)
27
NC
DO1
Digital Output
Not internally connected (10-bit option) /
Digital output bit (for 12-bit Option Only)
28
DO0
DO2
Digital Output
Digital output bit (LSB for 10-bit Option)
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WM8200
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ABSOLUTE MAXIMUM RATINGS
Absolute Maximum Ratings are stress ratings only. Permanent damage to the device may be caused by continuously operating at
or beyond these limits. Device functional operating limits and guaranteed performance specifications are given under Electrical
Characteristics at the test conditions specified.
ESD Sensitive Device. This device is manufactured on a CMOS process. It is therefore generically susceptible
to damage from excessive static voltages. Proper ESD precautions must be taken during handling and storage
of this device.
MIN
MAX
Digital supply voltage, DVDD to DGND
-0.3V
+3.63V
Analog supply voltage, AVDD to AGND
-0.3V
+3.63V
Maximum voltage difference between AGND and DGND
-0.3V
+0.3V
Voltage range digital input (SCLK, SDIN, CSB, CLAMP)
DGND - 0.3V
DVDD + 0.3V
Voltage range analog inputs
AGND - 0.3V
AVDD + 0.3V
Voltage range CLK, MODE inputs
CONDITION
AGND - 0.3V
AVDD + 0.3V
Operating junction temperature range, TJ
-40°C
+150°C
Storage temperature
-65°C
+150°C
Package Body Temperature (soldering 10 seconds)
+240°C
Package Body Temperature (soldering 2 minutes)
+183°C
RECOMMENDED OPERATING CONDITIONS
PARAMETER
MIN
NOM
MAX
UNIT
Digital supply range
DVDD
3.0
3.3
3.6
V
Analog supply range
AVDD
3.0
3.3
3.6
Ground
Clock frequency
SYMBOL
DGND, AGND
fCLK
Clock duty cycle
Operating Free Air Temperature
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TEST CONDITIONS
0
5
45
TA
-40
40
50
V
V
MHz
55
%
85
°C
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WM8200
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ELECTRICAL CHARACTERISTICS
Test Conditions:
AVDD = DVDD = 3.0V, fCLK = 40MHz, 50% duty cycle, MODE = AVDD, VREF=1.0V (REFT = 2.0V, REFB = 1.0V),
PGA gain = 1.0, TA = TMIN to TMAX, unless otherwise stated.
PARAMETER
SYMBOL
TEST CONDITIONS
MIN
TYP
MAX
UNIT
DC Accuracy
Integral nonlinearity
INL
±1.0
LSB
Differential nonlinearity
DNL
±0.3
LSB
Offset error
0.7
% of FSR
Full scale error
2.2
% of FSR
Missing codes
No missing codes guaranteed
Analogue Input Signal to AIN pins
Differential analogue input
voltage (AINP-AINN)
PGA=1x gain
-1
Switched input capacitance
1
1.2
V
pF
Conversion Characteristics
Conversion frequency
fCLK
5
Pipeline delay
40
MHz
cycles of
CLK
4
Dynamic Performance (differential input mode)
Effective number of bits
ENOB
Spurious free dynamic range
SFDR
Total harmonic distortion
THD
Signal to noise ratio
SNR
Signal to noise and distortion
ratio
SINAD
fIN = 4.8MHz
9.6
fIN = 20MHz
9.5
fIN = 4.8MHz
72
fIN = 20MHz
70
fIN = 4.8MHz
-72.5
fIN = 20MHz
-71.6
fIN = 4.8MHz
60
fIN = 20MHz
57
fIN = 4.8MHz
59.7
fIN = 20MHz
59.6
bits
dB
dB
dB
dB
PGA
Gain range (linear scale)
0.5
Gain step size (linear scale)
4
V/V
0.5
V/V
10
bits
Clamp
Clamp DAC resolution
Clamp DAC output voltage
REFB
Clamp DAC DNL
REFT
±1
Clamp output voltage error
-40
V
LSB
40
mV
REFB, REFT internal ADC reference voltage outputs (MODE= AVDD)
Reference voltage top, REFT
(AVDD=3V)
VREF = 0.5V
VREF= 1.0V
2
Reference voltage bottom,
REFB (AVDD=3V)
VREF = 0.5V
1.25
VREF= 1.0V
1
1.75
VREF Input / Output specifications (ADC Input Range = VREFx2)
Internal 0.5V reference to VREF
REFSENSE = VREF
0.5
V
Internal 1V reference to VREF
REFSENSE = AGND
1
V
External reference applied to
VREF pin
REFSENSE = AVDD
Input impedance in internal ADC
reference mode
REFSENSE = AVDD,
MODE = AVDD
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0.5
1
14
V
kΩ
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Test Conditions:
AVDD = DVDD = 3.0V, fCLK = 40MHz, 50% duty cycle, MODE = AVDD, VREF=1.0V (REFT = 2.0V, REFB = 1.0V),
PGA gain = 1.0, TA = TMIN to TMAX, unless otherwise stated.
PARAMETER
SYMBOL
TEST CONDITIONS
MIN
TYP
MAX
UNIT
Power Supplies
Analogue supply current
IAVDD
Digital supply current
IDVDD
Standby power consumption
(digital and analogue combined)
MODE = AGND
28.5
mA
MODE = AVDD
31
mA
CL = 10pF
5
mA
75
uW
IVDD(STBY)
Digital Logic Levels (CMOS Levels)
Input LOW level
VIL
(Note 1)
Input HIGH level
VIH
(Note 1)
Output LOW
VOL
IOL = -50µA
Output HIGH
VOH
IOH = 50µA
0.2 x VDD
V
0.4
V
0.8 x VDD
V
VDD – 0.4
V
Notes
1.
Digital input and output levels refer to the supply used for the input/output buffer on the relevant pin. CLK and MODE
refer to the AVDD supply, all other digital input/output refers to the DVDD supply.
CONTROL INTERFACE TIMING
tCSL
tCSH
CSB
tSCY
tSCH
tCSS
tSCL
tSCS
SCLK
SDIN
LSB
tDSU
tDHO
Figure 1: Control Interface Timing
Test Conditions
AVDD = DVDD = 3.0V, AGND = DGND = 0V, TA = TMIN to TMAX, unless otherwise stated
PARAMETER
SYMBOL
TEST CONDITIONS
MIN
TYP
MAX
UNIT
Program Register Input Information
SCLK rising edge to CSB rising
edge
tSCS
60
ns
SCLK pulse cycle time
tSCY
80
ns
SCLK pulse width low
tSCL
30
ns
SCLK pulse width high
tSCH
30
ns
SDIN to SCLK set-up time
tDSU
20
ns
SCLK to SDIN hold time
tDHO
20
ns
CSB pulse width low
tCSL
20
ns
CSB pulse width high
tCSH
20
ns
CSB rising to SCLK rising
tCSS
20
ns
Table 1 Control Interface Timing Information
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DEVICE DESCRIPTION
INTRODUCTION
The WM8200 is a high speed analogue to digital converter (ADC) with on-chip analogue preprocessing and reference generation, deisgned for applications such as composite video digitisation
digital copiers and high speed data acquisition. The integrated clamp and the coarse offset function
mean the device is ideally suited to CCD/CMOS input systems such as colour scanners, digital
copiers and digital cameras. A wide input voltage range between REFB and REFT allows the
WM8200 to be used in both imaging and communications systems.The chip architecture consists of:
•
•
High bandwidth sample and hold input, which can operate in differential or singleended mode
Programmable gain amplifier (PGA)
•
Voltage clamp for DC restoration that can take its reference from an on-chip 10-bit
DAC or an external source
•
•
•
Coarse offset function to allow clamping with single ended CCD style inputs
10-bit, 40MSPS pipeline analogue-to-digital converter (ADC) core
On-chip reference generator and reference buffer (external references can also be
used for applications where common or high precision references are required)
•
10-bit parallel output for ADC conversion. ADC data can be output in unsigned binary
or two’s complement format. An out-of-range output pin indicates when the input signal
is outside the converter’s range
Serial control interface to configure the operation of the device.
•
ANALOGUE SIGNAL PATH
The WM8200 analogue signal path consists of a DC clamp with a 10-bit clamp level DAC (discussed
under ‘DC Clamp’, below), a high-bandwidth sample and hold unit followed by a programmable gain
amplifier (PGA) and a fast 10-bit pipelined analogue to digital converter (ADC core).
REFT
AINP
AINN
X
VP+
SAMPLE
AND
HOLD
X-1
VQ+
ADC
CORE
PGA
VP-
VQREFB
Figure 2 Analogue Input Signal Flow
Figure 2 shows the signal flow through the sample and hold unit and the PGA to the ADC core,
where the process of analogue to digital conversion is performed against the ADC reference
voltages, REFT and REFB (their generation from internal or external reference sources is described
later).
SAMPLE AND HOLD
The differential analogue input signals can be connected directly to the AINN and AINP pins, either
DC coupled, AC coupled, or AC coupled with DC restoration using the WM8200 clamp circuit.
The differential sample and hold processes VINP and VINN with respect to the voltages applied to the
REFT and REFB pins, and produces a differential output VP = VP+ - VP- given by:
VP = AINP − AINN
For single-ended input signals, the signal can be DC or AC coupled to either AINN or AINNP, and a
suitable reference voltage must be applied to the other pin. Note of the input signal is applied to
AINN this will result in it being inverted during sampling.
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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
 REFT − REFB 
VQZS = −

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 ) ≤ [ AINP − AINN ] ≤ (REFT − REFB )
(2 × Gain )
(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.
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.
MODE
PIN
MODE
FUNCTION
COMMENTS
AGND
Full external
REFT = external
On-chip reference generator and reference buffer are
not used.
REFB = external
AVDD
Top/Bottom
REFTF =
AVDD + (REFTS − REFBS )
2
REFBF =
AVDD − (REFTS − REFBS )
2
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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DC CLAMP
The WM8200 incorporates a clamp function for restoring the DC reference level of AC coupled input
signals. When the clamp input pin is held high the internal clamp amplifier forces the voltage at
AINP to equal the clamp reference voltage, setting the DC level at AINP.
The clamp reference voltage comes from the on-chip 10-bit Clamp Level DAC by default, however it
can be applied to the AINN pin if the CLPSEL register bit is set high.
Control
Register
+
CLAMP
SW1
CIN
RIN
10-Bit DAC
Vclamp
-
AINP
S/H
AINN
Figure 3 Schematic of Clamp Circuitry
Figure 4 shows an example of using the clamp to restore the black level of a composite video input
AC coupled to AINN. While the clamp pin is held high, the clamp amplifier forces the voltage at AINN
to equal the clamp reference voltage, setting the DC voltage at AINN for the video black level.
Line sync
Black
level
VIDEO AT
AINN
CLAMP
Figure 4 Example Waveforms for Line-Clamping to a Video Input Black Level
If the CLAMP amplifier is not required it can be disabled for power saving purposes by setting the
CLPDIS register bit to high.
CLAMP DAC OUTPUT VOLTAGE RANGE AND LIMITS
Important: When using the internal clamp DAC in Top/Bottom or Centre Span Mode, the user must
ensure that the desired DC clamp level at AIN lies within the voltage range REFB to REFT. This is
because the clamp DAC voltage is constrained to lie within this range REFB to REFT. Specifically:
VDAC = REFB + (REFT – REFB) x (0.006 +0.988 x (DAC_code)/1024)
DAC codes can range from 0 to 1023. Figure 5 shows the clamp DAC output voltage versus the
DAC code.
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VDAC
VREFTF
VREFBF + 0.006(VREFTF-VREFBF)
VREFBF + 0.987(VREFTF-VREFBF)
VREFBF
0
1023
DAC
code
Figure 5 Clamp DAC Output Voltage versus DAC Register Code Value
COARSE OFFSET
The WM8200 features a coarse offset feature which allows it to accommodate both positive-going
and negative-going input signals when using the DC clamp. This feature is enabled by setting the
PGAOFF register bit to high.
DIAGRAM SHOWING COARSE OFFSET TO BE INSERTED
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CONTROL INTERFACE
The internal control registers are programmable via the 3-wire serial interface. SDIN is used for the
program data, SCLK is used to clock in the data and CSB is used to latch in the program data. The
3-wire interface protocol is shown in Figure 6.
CSB
SCLK
SDIN
A3
A2
A1
A0
D7
D6
D5
ADDRESS
D4
D3
D2
D1
D0
DATA
Figure 6: 3-Wire Serial Interface
1.
A[3:0] are Control Address Bits
2.
D[7:0] are Control Data Bits
3.
CSB is edge sensitive – the data is latched on the rising edge of CSB.
REGISTER MAP
Table 3 shows the location of each control bit used to determine the operation of the WM8200. The
procedure for programming the register map is described in the CONTROL INTERFACE section.
ADDR
NAME
BIT
DEFAULT
(HEX)
B7
B6
B5
B4
B3
B2
B1
B0
DAC[0]
0000
Clamp Reg 1
00
DAC[7]
DAC[6]
DAC[5]
DAC[4]
DAC[3]
DAC[2]
DAC[1]
0001
Clamp Reg 2
00
0
0
0
0
0
0
DAC[9]
DAC[8]
0010
PGA Control
01
0
0
PGASENSE
PGAOFF
0
PGA[2]
PGA[1]
PGA[0]
0011
Control
00
0
0
0
CLPSEL
OEB
TWOSC
CLDIS
PD
0100 1111
Reserved
00
Reserved, do not write to these register locations
Table 3: Register Map
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REGISTER MAP DESCRIPTION
REGISTER
BIT
BIT
NAMES
DEFAULT
Clamp
Register 1
7:0
DAC[7:0]
00000000
Clamp DAC value bits 7 to 0 (Unsigned binary format)
Clamp
Register 2
1:0
DAC[9:8]
00
Clamp DAC value bits 9 to 8 (Unsigned binary format)
PGA
Control
Register
2:0
PGA[2:0]
001
PGA Gain control
Control
Register
DESCRIPTION
000: PGA Gain = 0.5x
100: PGA Gain = 2.5x
001: PGA Gain = 1.0x
101: PGA Gain = 3.0x
010: PGA Gain = 1.5x
110: PGA Gain = 3.5x
011: PGA Gain = 2.0x
111: PGA Gain = 4.0x
4
PGAOFF
0
Enables a coarse offset to be added to the output of the PGA. Allows the
use of single ended input signals with no loss of ADC dynamic range.
5
PGASENSE
0
Determines the sense of the coarse offset added to the output of the PGA.
This bit only has an effect when PGAOFF=1.
0: PGA output is offset to full-scale positive for zero differential input
(suitable for negative going video).
1: PGA output is offset to full-scale negative for zero differential input
(suitable for positive going video).
0
PD
0
Device power-down
0: Device is powered up
1: Device is powered down.
1
CLDIS
0
CLAMP amplifier enable (for power saving)
0: Enable
1: Disable
2
TWOSC
0
Output data format
0: Unsigned binary
1: Twos complement
3
OEB
0
Output data pin enable
0: DO[9:0]/DO[11:0] enabled
1: DO[9:0]/DO[11:0] disabled (outputs are high impedance).
4
CLPSEL
0
Clamp source select
0: Clamp to output of Clamp DAC
1: Clamp to voltage on AINN input pin
POWER MANAGEMENT
In power-sensitive applications (such as battery-powered systems) where the WM8200 ADC is not
required to convert continuously, power can be saved between conversion intervals by placing the
WM8200 into Power Down mode. This is achieved by setting bit 0 (PD) of the control register to 1. In
Power Down mode, the device typically consumes less than 3mW of power. Power down mode is
exited by resetting control register bit 1 to 0. On power up from long periods of power down, the
WM8200 typically requires 5ms of wake up time before valid conversion results are available.
In systems where the ADC must run continuously, but where the clamp is not required, the supply
current can be reduced by approximately 1.2mA by setting the control register bit 1 (CLDIS), which
disables the clamp circuit. Similarly, when REFSENSE is tied to AVDD, the reference generator is
disabled and supply current reduced by approximately 1.2mA.
DATA OUTPUT FORMAT
While the OEB pin is held low, ADC conversion results are output at the data I/O pins DO[0] (LSB) to
DO[9] (MSB). The default output data format is unsigned binary (output codes 0 to 1023). This can
be switched to two’s complement format (output codes -512 to 511) by setting control register bit 2
(TWOSC) to 1.
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REFERENCE VOLTAGE GENERATION
The WM8200 incorporates an on-chip 0.5V bandgap voltage reference that can be used to derive a
temperature and supply independent voltage on pin VREF. The VREF output can be used for driving
external loads or setting the ADC input range. The voltage is programmed via connections made to
the REFSENSE pin as shown in Table 4.
REFSENSE
VREF output
Refer to
AGND
1.0V
Figure 7
AVDD
Hi impedance – A1 amplifier disabled
Figure 8
If using the ADC reference generator then an
external VREF source must be applied to the
VREF pin.
Connect to VREF
0.5V
Figure 9
R network to VREF / AGND
Between 0.5 V and 1 V
VREF=0.5x(1+Ra/Rb)
Figure 10
Table 4: – VREF output control by REFSENSE connection
+
0.5V
-
+
A1
-
VREF
10k
+
0.5V
-
+
A1
-
VREF
REFSENSE
REFSENSE
10k
AVSS
AVSS
Figure 7: VREF=1V
+
0.5V
-
+
A1
-
Figure 9: VREF=0.5V
VREF
REFSENSE = AVDD
+
0.5V
-
+
A1
-
VREF
Ra
REFSENSE
Rb
AVSS
Figure 8: VREF=Hi Impedance
AVSS
Figure 10: VREF between 0.5 and 1V
When enabled, the on-chip voltage reference should be externally decoupled (see Reference
Decoupling Section for details).
In internal ADC references mode (MODE=AVDD), the voltages at REFT and REFB are:
REFT = (AVDD + VREF) / 2
REFB = (AVDD – VREF) / 2
If external ADC references mode (MODE=AVSS), the average value of the external voltages applied
to REFT and REFB should be AVDD/2 for correct device operation.
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WM8200
Product Preview
REFERENCE DECOUPLING
VREF, REFT and REFB must be decoupled as shown in Figure 11.
VREF
+
10 µ F
100 nF
WM8200-10/12
REFT
100 nF
+
10 µ F
100 nF
REFB
100 nF
Figure 11: VREF, REFT and REFB decoupling
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PP Rev 1.22 March 2002
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WM8200
Product Preview
PACKAGE DIMENSIONS
FL: 28 PIN QFN PLASTIC PACKAGE 5 X 5 X 0.9 mm BODY, 0.50 mm LEAD PITCH
DM023.C
TOP VIEW
D2
B
D2/2
27
22
D
INDEX AREA
(D/2 X E/2)
28
L
21
1
2
E2/2
A
A
15
E2
E
7
SEE DETAIL B
2X
13
14
e
8
B
aaa C
b
ccc M C A B
2X
aaa C
DETAIL B
DATUM
R
ccc C
(A3)
A
0.08 C
SEATING PLANE
A1
e
C
TERMINAL TIP
1
Symbols
A
A1
A3
b
D
D2
E
E2
e
L
R
aaa
ccc
REF:
MIN
0.80
0
0.18
3.2
3.2
Dimensions (mm)
NOM
MAX
0.90
1.00
0.02
0.05
0.2 REF
0.23
0.30
5.00 BSC
3.3
3.4
5.00 BSC
3.3
3.4
0.5 BSC
0.4
0.45
NOTE
2
1
2
2
0.35
b(min)/2
Tolerances of Form and Position
0.15
0.10
JEDEC.95, MO-220, VARIATION VHHD-1
NOTES:
1. DIMENSION b APPLIED TO METALLIZED TERMINAL AND IS MEASURED BETWEEN 0.25 mm AND 0.30 mm FROM TERMINAL TIP.
2. FALLS WITHIN JEDEC.95, MO-220 WITH THE EXCEPTION OF D2, E2, A3:
D2,E2: LARGER PAD SIZE CHOSEN WHICH IS JUST OUTSIDE JEDEC SPECIFICATION
A3:
NOMINAL VALUE LESS THAN JEDEC
3. ALL DIMENSIONS ARE IN MILLIMETRES
4. THIS DRAWING IS SUBJECT TO CHANGE WITHOUT NOTICE.
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WM8200
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IMPORTANT NOTICE
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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