WM9705 Datasheet, PDF (10/55 Pages) Wolfson Microelectronics plc – Multimedia AC97 CODEC with Integrated Touch Screen Controller

WM9705
Production Data
Test Characteristics:
AVDD = 3.3V, DVDD = 3.3V, MCLK = 24.576MHz, TA = 25^oC, unless otherwise stated.
PARAMETER
PEN and AUXILIARY INPUT ADC
Resolution
Differential non-linearity error
Integral non-linearity error
Offset error
Gain error
Noise
Conversion time
Acquisition time
Throughput rate
Multiplexer settling time
ADC positive reference
SYMBOL
DNL
INL
ADC negative reference
ADC sampling capacitance
AUXADC input range (fullscale)
AUXADC input leakage current
BMON input range
BMON input impedance
BMON effective input
impedance (Note 3)
BMON input gain
PEN INTERFACE
Full scale input range
Absolute input range
Capacitance
Leakage current
Screen switch on resistance
Pressure measurement current
External Pen-detect pull up
resistor value
Pen Detect Comparator
Threshold DAC Range
Pen Detect Comparator
Threshold DAC step size
PDDACR
PDDACLSB
TEST CONDITIONS
X conversion
Y conversion
auxiliary conversion
X conversion
Y conversion
auxiliary conversion
at sampling time
93.75Hz sample rate
Positive input
Negative input
PIL = 0
PIL = 1
MIN
AGND1
AGND1
1
0.1
TYP
12
+/-0.25
+/-2
+/-4
+/-4
500
20.8
15
500
X+ pin
Y+ pin
AVDD1
X- pin
Y- pin
AGND1
2
+/-0.5
30
7.7
1/3
AVDD
AVDD
0
5
+/-0.5
20
200
400
10
0.1
MAX
48
AVDD1
6.5V
100
1.65
UNIT
Bits
LSB
LSB
LSB
LSB
µVrms
µsec
µsec
kHz
nsec
V
V
pF
µA
kΩ
MΩ
V
V
pF
µA
Ω
µA
kΩ
V
V
Note:
1. Harmonic distortion on the headphone output decreases with output power – see Figure 3.
2. SNR is the ratio of 0dB signal amplitude to noise floor with no signal present (all 0s input code to DACs).
3. The input impedance of the BMON input is 30k to ground when the ADC is sampling and hi-Z when it is not. The effective
input resistance is calculated dependant on how often the battery is sampled by the user. 7.7MΩ is the effective
impedance if the battery is sampled once every 512 frames. For a fuller description of this and information on how to
calculate the effect input impedance please see the section on auxiliary conversions on pages 46.
4. ADC sampling capacitance allows the user to calculate the minimum external capacitance required for a stable ADC value.
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PD Rev 4.0 December 2003
10