ANALOG DEVICES ADMP521 Service Manual
Bottom Port and PDM Digital Output
ADMP521
Rev. A
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ADMP521
ADC
POWER
MANAGEMENT
CLK
DATA
V
DD
GND
PDM
MODULATOR
CHANNEL
SELECT
L/R SELECT
10141-001
BOTTOM TOP
10141-011
Data Sheet
FEATURES
Small and thin 4 mm × 3 mm × 1 mm surface-mount package
Omnidirectional response
Very high SNR: 65 dBA
Sensitivity of −26 dBFS
Extended frequency response from 100 Hz to 16 kHz
Low current consumption: 900 µA
Sleep mode for extended battery life, <1 µA consumption
120 dB maximum SPL
High PSR of −80 dBFS
Fourth-order Σ-Δ modulator
Digital PDM output
Compatible with Sn/Pb and Pb-free solder processes
RoHS/WEEE compliant
APPLICATIONS
Smartphones and feature phones
Tablet computers
Teleconferencing systems
Digital still and video cameras
Bluetooth headsets
Notebook PCs
Security and surveillance
Ultralow Noise Microphone with
FUNCTIONAL BLOCK DIAGRAM
Figure 1.
Figure 2. Isometric Views of ADMP521 Microphone Package
GENERAL DESCRIPTION
The ADMP5211 is a high performance, ultralow noise, low
power, digital output, bottom-ported omnidirectional MEMS
microphone. The ADMP521 consists of a MEMS microphone
element and an impedance converter amplifier followed by a
fourth-order sigma-delta (Σ-Δ) modulator. The digital interface
allows for the pulse density modulated (PDM) output of two
microphones to be time-multiplexed on a single data line using
a single clock. The ADMP521 is function and pin compatible with
the ADMP421 microphone, providing an easy upgrade path.
The ADMP521 has a very high signal-to-noise ratio (SNR) and
common sensitivity of −26 dBFS, making it an excellent choice
1
Protected by U.S. Patents 7,449,356; 7,825,484; 7,885,423; 7,961,897. Other patents are pending.
responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other
rights of third parties that may result from its use. Specifications subject to change without notice. No
license is granted by implication or otherwise under any patent or patent rights of Analog Devices.
for far field applications. The ADMP521 has an extended wideband frequency response resulting in natural sound with high
intelligibility. Low current consumption and a sleep mode with
less than 1 µA current consumption enables long battery life
for portable applications. The ADMP521 complies with the
TIA-920 Te l e -communications Telephone Terminal Equipment
Transmission Requirements for Wideband Digital Wireline
Telephones standard.
The ADMP521 is available in a thin 4 mm × 3 mm × 1 mm
surface-mount package. It is reflow solder compatible with
no sensitivity degradation. The ADMP521 is halide free.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700
www.analog.com
ADMP521 Data Sheet
TABLE OF CONTENTS
Features .............................................................................................. 1
Applications ....................................................................................... 1
Functional Block Diagram .............................................................. 1
General Description ......................................................................... 1
Revision History ............................................................................... 2
Specifications ..................................................................................... 3
Timing Characteristics ................................................................ 4
Absolute Maximum Ratings ............................................................ 5
ESD Caution .................................................................................. 5
Pin Configuration and Function Descriptions ............................. 6
Typical Performance Characteristics ............................................. 7
Theory of Operation ........................................................................ 8
PDM Data Format ........................................................................ 8
PDM Microphone Sensitivity ..................................................... 8
Connecting PDM Microphones ................................................. 9
Sleep Mode .....................................................................................9
Start-Up ..........................................................................................9
Applications Information .............................................................. 10
Interfacing with Analog Devices Codecs ................................ 10
Supporting Documents ............................................................. 10
PCB Design and Layout ................................................................. 11
Alternative PCB Land Patterns ................................................. 12
PCB Material and Thickness .................................................... 12
Handling Instructions .................................................................... 13
Pick-and-Place Equipment ....................................................... 13
Reflow Solder .............................................................................. 13
Board Wa sh ................................................................................. 13
Reliability Specifications ................................................................ 14
Outline Dimensions ....................................................................... 15
Ordering Guide .......................................................................... 15
REVISION HISTORY
4/12—Rev. 0 to Rev. A
Changes to General Description Section ...................................... 1
Changed Supply Voltage Min Parameter from 1.65 V to 1.8 V ... 3
Changed 500 Hours to 1000 Hours in Table 7 ............................ 14
2/12—Revision 0: Initial Version
Rev. A | Page 2 of 16
Data Sheet ADMP521
PERFORMANCE
Dynamic Range
Derived from EIN and maximum acoustic input
91 dB
Input Voltage Low (VIL)
0.35 × VDD
V
SPECIFICATIONS
TA = 25°C, VDD = 1.8 V, CLK = 2.4 MHz, unless otherwise noted. All minimum and maximum specifications are guaranteed. Typical
specifications are not guaranteed.
Table 1.
Parameter Test Conditions/Comments Min Typ Max Unit
Directionality Omni
Sensitivity1 1 kHz, 94 dB sound pressure level (SPL) −29 −26 −23 dBFS
Signal-to-Noise Ratio (SNR) 20 Hz to 20 kHz, A-weighted 65 dBA
Equivalent Input Noise (EIN) 20 Hz to 20 kHz, A-weighted 29 dBA SPL
Frequency Response2 Low frequency −3 dB point 100 Hz
High frequency −3 dB point 16 kHz
Deviation limits from flat response within pass band −3/+8 dB
Total Harmonic Distortion (THD) 105 dB SPL 2.5 %
Power Supply Rejection (PSR) 217 Hz, 100 mV p-p sine wave superimposed on
V
= 1.8 V
DD
Maximum Acoustic Input Peak 120 dB SPL
POWER SUPPLY
Supply Voltage (VDD) 1.8 3.3 V
Supply Current (IS)
Normal Mode VDD = 1.8 V 0.9 1.0 mA
VDD = 3.3 V 1.0 1.2 mA
Sleep Mode3 VDD = 1.8 V 0.5 µA
VDD = 3.3 V 0.8 µA
DIGITAL INPUT/OUTPUT CHARACTERISTICS
Input Voltage High (VIH) 0.65 × VDD V
−80 dBFS
Output Voltage High (VOH) I
Output Voltage Low (VOL) I
= 0.5 mA 0.7 × VDD VDD V
LOAD
= 0.5 mA 0 0.3 × VDD V
LOAD
Output DC Offset Percent of full scale 7 %
Latency <30 µs
Noise Floor 20 Hz to 20 kHz, A-weighted −91 dBFS
1
Relative to the rms level of a sine wave with positive amplitude equal to 100% 1s density and negative amplitude equal to 0% 1s density.
2
See Figure 7 and Figure 8.
3
The microphone enters sleep mode when clock frequency is less than 1 kHz.
Rev. A | Page 3 of 16
ADMP521 Data Sheet
SLEEP MODE
INPUT
t
DATA2 (left) disabled after falling clock edge
5 30
ns
t
CLKIN
CLK
DATA2
DATA1
t
2OUTDIS
t
1OUTDIS
t
2OUTEN
t
1OUTEN
10141-002
TIMING CHARACTERISTICS
Table 2.
Parameter Description Min Typ Max Unit
Sleep Time Time from CLK falling < 1 kHz 1 ms
Wake-Up Time Time from CLK rising > 1 kHz, power on 10 ms
t
Input clock period 326 800 ns
CLKIN
Clock Frequency (CLK) 1.25 2.41 3.072 MHz
Clock Duty Ratio 40 60 %
OUTPUT
t
DATA1 (right) driven after falling clock edge 40 ns
1OUTEN
t
DATA1 (right) disabled after rising clock edge 5 30 ns
1OUTDIS
t
DATA2 (left) driven after rising clock edge 40 ns
2OUTEN
2OUTDIS
1
The microphone operates at any clock frequency between 1.0 MHz and 3.3 MHz. Some specifications may not be guaranteed at frequencies other than 2.4 MHz.
Timing Diagram
Figure 3. Pulse Density Modulated Output Timing
Rev. A | Page 4 of 16
Data Sheet ADMP521
Digital Pin Input Voltage
−0.3 V to VDD + 0.3 V or +3.6 V,
Test Condition B
t
P
t
L
t
25°C TO PEAK
t
S
PREHEAT
CRITICAL ZONE
T
L
TO T
P
TEMPERATURE
TIME
RAMP-DOWN
RAMP-UP
T
SMIN
T
SMAX
T
P
T
L
10141-003
Ramp-Up Rate (T
to TL)
1.25°C/sec
1.25°C/sec
ABSOLUTE MAXIMUM RATINGS
Table 3.
Parameter Rating
Supply Voltage −0.3 V to +3.6 V
whichever is less
Sound Pressure Level 160 dB
Mechanical Shock 10,000 g
Vibration Per MIL-STD-883 Method 2007,
Stresses above those listed under Absolute Maximum Ratings
may cause permanent damage to the device. This is a stress
rating only; functional operation of the device at these or any
other conditions above those indicated in the operational
section of this specification is not implied. Exposure to absolute
maximum rating conditions for extended periods may affect
device reliability.
Temperature Range −40°C to +85°C
ESD CAUTION
Figure 4. Recommended Soldering Profile Limits
Table 4. Recommended Soldering Profile Limits
Profile Feature Sn63/Pb37 Pb-Free
Average Ramp Rate (TL to TP) 1.25°C/sec maximum 1.25°C/sec maximum
Preheat
Minimum Temperature (T
Maximum Temperature (T
Time (T
SMIN
to T
), tS 60 sec to 75 sec 60 sec to 75 sec
SMAX
SMAX
) 100°C 100°C
SMIN
) 150°C 200°C
SMAX
Time Maintained Above Liquidous (tL) 45 sec to 75 sec ~50 sec
Liquidous Temperature (TL) 183°C 217°C
Peak Temperature (TP) 215°C +3°C/−3°C 260°C + 0°C/−5°C
Time Within 5°C of Actual Peak Temperature (tP) 20 sec to 30 sec 20 sec to 30 sec
Ramp-Down Rate 3°C/sec maximum 3°C/sec maximum
Time 25°C (t25°C) to Peak Temperature 5 minute maximum 5 minute maximum
Rev. A | Page 5 of 16
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