EV_INMP621-FX - InvenSense - Product.Network

INMP621

Wide Dynamic Range Microphone with PDM Digital Output

GENERAL DESCRIPTION

The INMP621*is a high sound pressure level (SPL), ultra-low

noise, low power, digital output, bottom ported

omnidirectional MEMS microphone. This microphone clips at

133 dB SPL, which is useful for clearly capturing audio in loud

environments. The INMP621 consists of a MEMS microphone

element and an impedance converter amplifier followed by a

fourth-order Σ-Δ modulator. The digital interface allows the

pulse density modulated (PDM) output of two microphones

to be time multiplexed on a single data line using a single

clock. The INMP621 is pin compatible with the INMP421 and

INMP521 microphones, providing an easy upgrade path.

The INMP621 has a high SNR of 65 dBA and sensitivity of

−46 dBFS. The INMP621 has an extended wideband frequency

response, resulting in natural sound with high intelligibility.

Low current consumption and a sleep mode at less than

5.5 µA enables long battery life for portable applications.

The INMP621 is available in a thin 4 × 3 × 1 mm surface-

mount package. It is reflow solder compatible with

no sensitivity degradation.

*Protected by U.S. Patents 7,449,356; 7,825,484; 7,885,423; and 7,961,897.

Other patents are pending.

APPLICATIONS

• Tablet Computers

• Notebook PCs

• Smartphones

• Microphone Arrays

• Teleconferencing Systems

• Digital Still and Video Cameras

• Bluetooth Headsets

• Security and Surveillance

FEATURES

• High Acoustic Overload Point of 133 dB SPL

• Small, Thin 4 × 3 × 1 mm Surface-Mount Package

• Omnidirectional Response

• Very High Signal-to-Noise Ratio (SNR): 65 dBA

• Sensitivity of −46 dBFS

• Extended Frequency Response from 45 Hz to >20 kHz

• Low Current Consumption: 1.2 mA

• Sleep Mode for Extended Battery Life: 5.5 µA

• High Power Supply Rejection (PSR): −100 dBFS

• Fourth-Order Σ-Δ Modulator

• Digital Pulse Density Modulation (PDM) Output

• Compatible with Sn/Pb and Pb-Free Solder Processes

• RoHS/WEEE Compliant

ORDERING INFORMATION

PART

TEMP RANGE

INMP621ACEZ-R0*

−40°C to +85°C

INMP621ACEZ-R7†

−40°C to +85°C

EV_INMP621-FX

—

* – 13” Tape and Reel

† – 7” Tape and reel to be discontinued. Check with

sales@invensense.com for availability.

INMP621

ADC

POWER

MANAGEMENT

CLK

DATA

VDD

GND

PDM

MODULATOR

CHANNEL

SELECT

L/R SELECT

BOTTOM TOP

FUNCTIONAL BLOCK DIAGRAM

InvenSense reserves the right to change the detail

specifications as may be required to permit

improvements in the design of its products.

InvenSense Inc.

1745 Technology Drive, San Jose, CA 95110 U.S.A

+1(408) 988–7339

www.invensense.com

Document Number: DS-INMP621-00

Revision: 1.1

Rev Date: 05/21/2014

INMP621

TABLE OF CONTENTS

General Description ........................................................................................................................................................ 1

Functional Block Diagram ............................................................................................................................................... 1

Applications .................................................................................................................................................................... 1

Features .......................................................................................................................................................................... 1

Ordering Information ...................................................................................................................................................... 1

Table of Contents ............................................................................................................................................................ 2

Specifications .................................................................................................................................................................. 4

Table 1. Electrical Characteristics ................................................................................................................................... 4

Table 2. Timing Characteristics ....................................................................................................................................... 5

Timing Diagram ............................................................................................................................................................... 5

Absolute Maximum Ratings ............................................................................................................................................ 6

Table 3. Absolute Maximum Ratings .............................................................................................................................. 6

ESD Caution ..................................................................................................................................................................... 6

Soldering Profile .............................................................................................................................................................. 7

Table 4. Recommended Soldering Profile* ..................................................................................................................... 7

Pin Configurations And Function Descriptions ............................................................................................................... 8

Table 5. Pin Function Descriptions .................................................................................................................................. 8

Typical Performance Characteristics ............................................................................................................................... 9

Theory Of Operation ..................................................................................................................................................... 10

PDM Data Format ......................................................................................................................................................... 10

Table 6. INMP621 Channel Setting ............................................................................................................................... 10

PDM Microphone Sensitivity ........................................................................................................................................ 11

Dynamic Range Considerations .................................................................................................................................... 12

Connecting PDM Microphones ..................................................................................................................................... 12

Sleep Mode ................................................................................................................................................................... 14

Start-Up Time ................................................................................................................................................................ 14

Supporting Documents ................................................................................................................................................. 15

Evaluation Board User Guide ........................................................................................................................................ 15

application Note (product Specific) .............................................................................................................................. 15

Application Notes (general) .......................................................................................................................................... 15

PCB Design And Land Pattern Layout ........................................................................................................................... 16

Alternative PCB Land Patterns ...................................................................................................................................... 17

PCB Material And Thickness ......................................................................................................................................... 17

Handling Instructions .................................................................................................................................................... 18

Pick And Place Equipment ............................................................................................................................................ 18

Reflow Solder ................................................................................................................................................................ 18

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Document Number: DS-INMP621-00

Revision: 1.1

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INMP621

Board Wash ................................................................................................................................................................... 18

Outline Dimensions ....................................................................................................................................................... 19

Ordering Guide ............................................................................................................................................................. 20

Revision History ............................................................................................................................................................ 20

Compliance Declaration Disclaimer .............................................................................................................................. 21

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Document Number: DS-INMP621-00

Revision: 1.1

Rev Date: 05/21/2014

INMP621

SPECIFICATIONS

TABLE 1. ELECTRICAL CHARACTERISTICS

(TA = −40 to 85°C, VDD = 1.8 to 3.3 V, CLK = 3.072 MHz, CLOAD = 30 pF, unless otherwise noted. All minimum and maximum

specifications are guaranteed across temperature, voltage, and clock frequency specified in Table 1 and Table 2, unless otherwise

noted. Typical specifications are not guaranteed.)

PARAMETER

CONDITIONS

MIN

TYP

MAX

UNITS

NOTES

PERFORMANCE

Directionality

Omni

Output Polarity

Input acoustic pressure vs.

output data

Inverted

Sensitivity

1kHz, 94 dB SPL

−48

−46

−44

dBFS

1, 2

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

Acoustic Dynamic Range

Digital Dynamic Range

Derived from EIN and

acoustic overload point

104 dB

Derived from EIN and full-

scale acoustic level

111 dB

Frequency Response

Low frequency −3 dB point

High frequency −3 dB

point

>20 kHz

Total Harmonic Distortion (THD)

105 dB SPL

0.35

Power Supply Rejection (PSR)

217 Hz, 100 mV p-p square

wave superimposed on

VDD = 1.8 V, A-weighted

−100 dBFS

Power Supply Rejection—Swept Sine

1 kHz sine wave

−113

dBFS

Acoustic Overload Point

10% THD

133

dB SPL

Full-Scale Acoustic Level

0 dBFS output

140

dB SPL

POWER SUPPLY

Supply Voltage (VDD)

1.62

3.63

Supply Current (IS)

VDD = 1.8 V Normal Mode

1.2 1.5 mA

Sleep Mode 5.5 µA 4

VDD = 3.3 V

Normal Mode

1.3

1.6

Sleep Mode

µA

DIGITAL INPUT/OUTPUT CHARACTERISTICS

Input Voltage High (VIH) 0.65 x VDD V

Input Voltage Low (VIL) 0.35 x VDD V

Output Voltage High (V

)

ILOAD = 0.5 mA 0.7 x VDD VDD

Output Voltage Low (V

)

ILOAD = 0.5 mA 0 0.3 x VDD

Output DC Offset

Percent of full scale

Latency

<30

µs

Noise Floor

20 Hz to 20 kHz, A-

weighted

−111 dBFS

Note 1: Sensitivity is relative to the RMS level of a sine wave with positive amplitude equal to 100% logical 1s density and negative amplitude equal to 0% logical 1s

density.

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Document Number: DS-INMP621-00

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INMP621

Note 2: The ±2 dB sensitivity specification is valid for CLK = 3.072 MHz. At lower clock frequencies, the minimum and maximum specifications are −49 dBFS and −43

dBFS, respectively.

Note 3: See Figure 4 and Figure 5.

Note 4: The microphone enters sleep mode when the clock frequency is less than 1 kHz.

TABLE 2. TIMING CHARACTERISTICS

PARAMETER

CONDITIONS

MIN

TYP

MAX

UNITS

NOTES

SLEEP MODE

Sleep Time

Time from CLK falling < 1

kHz

µs

Wake-Up Time

Time from CLK rising > 1

kHz to output within 3 dB

of final sensitivity, power

INPUT

tCLKIN Input clock period

270

1000

Clock Frequency (CLK)

1.0

3.072

3.6

MHz 1

Clock Duty Cycle

OUTPUT

T1OUTEN

DATA1 (right) driven after

falling clock edge

T1OUTDIS

DATA1 (right) disabled after

rising clock edge

T2OUTEN

DATA2 (left) driven after

rising clock edge

T2OUTDIS

DATA2 (left) disabled after

falling clock edge

Note 1: The microphone operates at any clock frequency between 1.0 MHz and 3.6 MHz. Some specifications may not be guaranteed at frequencies other than 3.072 MHz.

TIMING DIAGRAM

Figure 1. Pulse Density Modulated Output Timing

CLKIN

CLK

DATA2

DATA1

2OUTDIS

1OUTDIS

2OUTEN

1OUTEN

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Document Number: DS-INMP621-00

Revision: 1.1

Rev Date: 05/21/2014

INMP621

ABSOLUTE MAXIMUM RATINGS

Stress above those listed as Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only

and functional operation of the device at these conditions is not implied. Exposure to the absolute maximum ratings conditions for

extended periods may affect device reliability.

TABLE 3. ABSOLUTE MAXIMUM RATINGS

PARAMETER

RATING

Supply Voltage (VDD)

−0.3 V to +3.63 V

Digital Pin Input Voltage

−0.3 V to (VDD) + 0.3 V or 3.63 V, whichever is less

Sound Pressure Level

160 dB

Mechanical Shock

10,000 g

Vibration

Per MIL-STD-883 Method 2007, Test Condition B

Operating Temperature Range

−40°C to +85°C

Storage Temperature Range

−55°C to +150°C

ESD CAUTION

ESD (electrostatic discharge) sensitive device.

Charged devices and circuit boards can

discharge without detection. Although this

product features patented or proprietary

protection circuitry, damage may occur on

devices subjected to high energy ESD.

Therefore proper ESD precautions should be

taken to avoid performance degradation or

loss of functionality.

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Document Number: DS-INMP621-00

Revision: 1.1

Rev Date: 05/21/2014

INMP621

SOLDERING PROFILE

Figure 2. Recommended Soldering Profile Limits

TABLE 4. RECOMMENDED SOLDERING PROFILE*

PROFILE FEATURE

Sn63/Pb37

Pb-Free

Average Ramp Rate (T

to T

)

1.25°C/sec max

Preheat

Minimum Temperature

(TSMIN)

100°C 100°C

Minimum Temperature

(TSMIN)

150°C 200°C

Time (TSMIN to TSMAX), tS 60 sec to 75 sec 60 sec to 75 sec

Ramp-Up Rate (TSMAX to TL) 1.25°C/sec 1.25°C/sec

Time Maintained Above Liquidous (tL)

45 sec to 75 sec

~50 sec

Liquidous Temperature (TL)

183°C

217°C

Peak Temperature (T

)

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 max

3°C/sec max

Time +25°C (t25°C) to Peak Temperature 5 min max

5 min max

*The reflow profile in Table 4 is recommended for board manufacturing with InvenSense MEMS microphones. All

microphones are also compatible with the J-STD-020 profile.

t25°C

TO PEAK TEMPERATURE

PREHEAT

CRITICAL ZONE

TO T

TEMPERATURE

TIME

RAMP-DOWN

RAMP-UP

SMIN

SMAX

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Document Number: DS-INMP621-00

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INMP621

PIN CONFIGURATIONS AND FUNCTION DESCRIPTIONS

Figure 3. Pin Configuration

TABLE 5. PIN FUNCTION DESCRIPTIONS

PIN NAME FUNCTION

CLK

Clock Input to Microphone

2 L/R SELECT

Left Channel or Right Channel Select:

DATA 1 (right): L/R SELECT tied to GND

DATA 2 (left): L/R SELECT tied to VDD

3 GND Ground

4 VDD

Power Supply. For best performance and to avoid potential parasitic artifacts, place a 0.1 µF

(100 nF) ceramic type X7R capacitor between Pin 4 (VDD) and ground. Place the capacitor as

close to Pin 4 as possible.

5 DATA Digital Output Signal (DATA1 or DATA2)

CLK

L/R SELECT

GND

DATA

VDD

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Document Number: DS-INMP621-00

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INMP621

TYPICAL PERFORMANCE CHARACTERISTICS

Figure 4. Frequency Response Mask

Figure 5. Typical Frequency Response (Measured)

Figure 6. PSR vs. Frequency, 100 mV p-p Swept Sine Wave

Figure 7. Total Harmonic Distortion + Noise (THD+N) vs. Input SPL

Figure 8. Linearity

Figure 9. Clipping Characteristics

–20

–15

–10

–5

10 100 1k 10k

NORM ALIZED AMP LITUDE (dB)

FRE Q UE NCY ( Hz )

11609-106

–20

–15

–10

–5

10 100 1k 10k

NORM ALIZED AMP LITUDE (dB)

FREQUENCY ( Hz )

–140

–120

–100

–80

–60

–40

–20

100 1k 10k

PSR (dBFS)

FRE Q UE NCY ( Hz )

0.1

90 95 100 105 110 115 120 125 130 135 140

THD + N ( %)

INPUT LEVEL (d B SPL)

–50

–45

–40

–35

–30

–25

–20

–15

–10

–5

90 100 110 130120 140

OUTPUT LEVEL (dBFS)

INPUT LEVEL (d B SPL)

–0.8

–0.6

–0.4

–0.2

0.2

0.6

0.8

0.4

1.0

00.0002 0.0004 0.00080.0006 0.0010

OUTPUT LEVEL (D)

TIME (Seconds)

130dB SP L

132dB SP L

134dB SP L

136dB SP L

138dB SP L

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Document Number: DS-INMP621-00

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INMP621

THEORY OF OPERATION

PDM DATA FORMAT

The output from the DATA pin of the INMP621 is in pulse density modulated (PDM) format. This data is the 1-bit output of a fourth-

order Σ-Δ modulator. The data is encoded so that the left channel is clocked on the falling edge of CLK, and the right channel is clocked

on the rising edge of CLK. After driving the DATA signal high or low in the appropriate half frame of the CLK signal, the DATA driver of

the microphone tristates. In this way, two microphones, one set to the left channel and the other to the right, can drive a single DATA

line. See Figure 1 for a timing diagram of the PDM data format; the DATA1 and DATA2 lines shown in this figure are two halves of the

single physical DATA signal. Figure 10 shows a diagram of the two stereo channels sharing a common DATA line.

Figure 10. Stereo PDM Format

If only one microphone is connected to the DATA signal, the output is only clocked on a single edge (Figure 11). For example, a left

channel microphone is never clocked on the rising edge of CLK. In a single microphone application, each bit of the DATA signal is

typically held for the full CLK period until the next transition because the leakage of the DATA line is not enough to discharge the line

while the driver is tristated.

Figure 11. Mono PDM Format

See Table 6 for the channel assignments according to the logic level on the L/R SELECT pin.

TABLE 6. INMP621 CHANNEL SETTING

DATA2 ( L) DATA2 ( L)DATA1 ( R) DATA1 ( R)

CLK

DATA

DATA1 (R) DATA1(R) DATA1(R)

CLK

DATA

L/R SELECT Pin Setting

Channel

Low (tie to GND)

Right (DATA1)

High (tie to VDD)

Left (DATA2)

Page 10 of 21

Document Number: DS-INMP621-00

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INMP621

For PDM data, the density of the pulses indicates the signal amplitude. A high density of high pulses indicates a signal near positive

full scale, and a high density of low pulses indicates a signal near negative full scale. A perfect zero (DC) audio signal shows an

alternating pattern of high and low pulses.

The output PDM data signal has a small DC offset of about 3% of full scale. A high-pass filter in the codec that is connected to the digital

microphone and does not affect the performance of the microphone typically removes this DC signal.

PDM MICROPHONE SENSITIVITY

The sensitivity of a PDM output microphone is specified with the unit dBFS (decibels relative to digital full scale). A 0 dBFS sine wave

is defined as a signal whose peak just touches the full-scale code of the digital word (see Figure 12). This measurement convention also

means that signals with a different crest factor may have an RMS level higher than 0 dBFS. For example, a full-scale square wave has an

RMS level of 3 dBFS.

This definition of a 0 dBFS signal must be understood when measuring the sensitivity of the INMP621. A 1 kHz sine wave at a

94 dB SPL acoustic input to the INMP621 results in an output signal with a −46 dBFS level. The output digital word peaks at

−46 dB below the digital full-scale level. A common misunderstanding is that the output has an RMS level of −49 dBFS; however, this is

not true because of the definition of the 0 dBFS sine wave.

Figure 12. 1 kHz, 0 dBFS Sine Wave

There is not a commonly accepted unit of measurement to express the instantaneous level, as opposed to the RMS level of the

signal, of a digital signal output from the microphone. Some measurement systems express the instantaneous level of an individual

sample in units of D, where 1.0 D is digital full scale. In this case, a −46 dBFS sine wave has peaks at 0.005 D.

1.0

–1.0

–0.8

–0.6

–0.4

–0.2

0.2

0.4

0.6

0.8

00.9 1.00.80.70.60.50.40.30.20.1

DIGITAL AMPLITUDE (D)

TIME (ms)

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Document Number: DS-INMP621-00

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INMP621

DYNAMIC RANGE CONSIDERATIONS

The full-scale digital output (0 dBFS) of the INMP621 is mapped to an acoustic input of 140 dB SPL. The microphone clips (THD =

10%) at 133 dB SPL (see Figure 7); however, it continues to output an increasingly distorted signal above that point. The peak output

level, which is controlled by the modulator, limits at about −3 dBFS (see Figure 8).

To fully use the 111 dB digital dynamic range of the output data of the INMP621 in a design, the digital signal processor (DSP), analog-

to-digital converter (ADC), or codec circuit following it must be chosen carefully. The decimation filter that inputs the PDM signal from

the INMP621 must have a dynamic range sufficiently better than the dynamic range of the microphone so that the overall noise

performance of the system is not degraded. If the decimation filter has a dynamic range of 10 dB better than the microphone (121

dB), the overall system noise only degrades by 0.4 dB.

CONNECTING PDM MICROPHONES

A PDM output microphone is typically connected to a codec with a dedicated PDM input. This codec separately decodes the left and right

channels and filters the high sample rate modulated data back to the audio frequency band. This codec also generates the clock for the

PDM microphones or is synchronous with the source that is generating the clock. Figure 13 and Figure 14 show mono and stereo

connections of the INMP621 to a codec. The mono connection shows an INMP621 set to output data on the right channel. To output on

the left channel, tie the L/R SELECT pin to VDD instead of tying it to GND.

Figure 13. Mono PDM Microphone (Right Channel) Connection to Codec

CLOCK OUTPUT

CODEC

0.1µF

1.8V TO 3.3V

GND

L/R SELECT

DATA

INMP621

CLK

VDD

DATA INPUT

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INMP621

Figure 14. Stereo PDM Microphone Connection to Codec

Decouple the VDD pin of the INMP621 to GND with a 0.1 µF capacitor. Place this capacitor as close to VDD as the printed circuit board

(PCB) layout allows.

Do not use a pull-up or pull-down resistor on the PDM data signal line because it can pull the signal to an incorrect state during the period

that the signal line is tristated.

The DATA signal does not need to be buffered in normal use when the INMP621 microphone(s) is placed close to the codec on the PCB. If the DATA signal

must be driven over a long cable (>15 cm) or other large capacitive load, a digital buffer may be required. Only use a signal buffer on the

DATA line when one microphone is in use or after the point where two microphones are connected (see Figure 15). The DATA output of

each microphone in a stereo configuration cannot be individually buffered because the two buffer outputs cannot drive a single signal line. If a

buffer is used, take care to select one with low propagation delay so that the timing of the data connected to the codec is not corrupted.

CLOCK OUTPUT

CODEC

0.1µF

1.8 V TO 3.3 V

GND

L/R SELECT

DATA

INMP621

CLK

VDD

DATA INPUT

0.1µF

1.8 V TO 3.3 V

GND

L/R SELECT

DATA

INMP621

CLK

VDD

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Document Number: DS-INMP621-00

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INMP621

Figure 15. Buffered Connections Between Stereo INMP621s and a Codec

When long wires are used to connect the codec to the INMP621, a source termination resistor can be used on the clock output of the

codec instead of a buffer to minimize signal overshoot or ringing. Match the value of this resistor to the characteristic impedance of

the CLK trace on the PCB. Depending on the drive capability of the codec clock output, a buffer may still be needed, as shown in Figure

15.

SLEEP MODE

The microphone enters sleep mode when the clock frequency falls below 1 kHz. In this mode, the microphone data output is in a high

impedance state. The current consumption in sleep mode is less than 5.5 µA.

The INMP621 enters sleep mode within 1ms of the clock frequency falling below 1 kHz. The microphone wakes up from sleep mode

and begins to output data 32,768 cycles after the clock becomes active. For a 3.072 MHz clock, the microphone starts to output data in

10.7 ms. For a 2.4 MHz clock, the microphone starts to output data in 13.7 ms. The wake-up time, as specified in Table 2, indicates the

time from when the clock is enabled to when the INMP621 outputs data within 3 dB of its settled sensitivity.

START-UP TIME

The start-up time of the INMP621 from when the clock is active is the same as the wake-up time. The microphone starts up 32,768

cycles after the clock is active.

CLOCK OUTPUT

CODEC

DATA

INMP621

CLK

DATA INPUT

DATA

CLK

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Document Number: DS-INMP621-00

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INMP621

SUPPORTING DOCUMENTS

For additional information, see the following documents.

EVALUATION BOARD USER GUIDE

UG-326 PDM Digital Output MEMS Microphone Evaluation Board

APPLICATION NOTE (PRODUCT SPECIFIC)

AN-0078 High Performance Digital MEMS Microphone Simple Interface to a SigmaDSP Audio Codec

APPLICATION NOTES (GENERAL)

AN-1003 Recommendations for Mounting and Connecting the Invensense, Bottom-Ported MEMS Microphones

AN-1068 Reflow Soldering of the MEMS Microphone

AN-1112 Microphone Specifications Explained

AN-1124 Recommendations for Sealing Invensense, Bottom-Port MEMS Microphones from Dust and Liquid Ingress

AN-1140 Microphone Array Beamforming

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Document Number: DS-INMP621-00

Revision: 1.1

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INMP621

PCB DESIGN AND LAND PATTERN LAYOUT

The response of the INMP621 is not affected by the PCB hole size as long as the hole is not smaller than the sound port of the

microphone (0.25 mm, or 0.010 inch, in diameter). A 0.5 mm to 1 mm (0.020 inch to 0.040 inch) diameter for the hole is recommended.

Take care to align the hole in the microphone package with the hole in the PCB. The exact degree of the alignment does not affect the

microphone performance as long as the holes are not partially or completely blocked.

Dimensions shown in millimeters

Figure 16. Recommended PCB Land Pattern Layout

Dimensions shown in millimeters

Figure 17. Suggested Solder Paste Stencil Pattern Layout

0.40 × 0.60 (4× )

(0.30)

0.90

(0.30) ø1.70

3.80

(0.30)

0.35

2.80

2× R0.10

(0.30)

0.352.05

0.70

ø1.10

(1.000)

(0.550)

CENT ER LI NE

1.45

0.9

2.45

0.7

1.525

1.000

0.35

1.849

1.498 0. 205 WI DE

0.248 × 0.498 (2× )

0.248 × 1.148 (2× )

0.248 × 0.948 (2× )

1.498 × 0.248

0.398 × 0.298 (4× )

0.362 CUT (3×)

1.17

24° 24°

0.375

CENTER

LINE

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Document Number: DS-INMP621-00

Revision: 1.1

Rev Date: 05/21/2014

INMP621

ALTERNATIVE PCB LAND PATTERNS

The standard PCB land pattern of the INMP621 has a solid rectangle around the edge of the footprint that can make routing the

microphone signals more difficult in some board designs. This rectangle is used to improve the radio frequency (RF) immunity

performance of the INMP621; however, it is not necessary to have this full rectangle connected for electrical functionality. If a design

can tolerate reduced RF immunity, this rectangle can either be broken or removed completely from the PCB footprint. Figure 18 shows

an example PCB land pattern with no enclosing rectangle around the edge of the part, and Figure 19 shows an example PCB land

pattern with the rectangle broken on two sides so that the inner pads can be more easily routed on the PCB.

Figure 18. Example PCB Land Pattern with No Enclosing Rectangle

Figure 19. Example PCB Land Pattern with Broken Enclosing Rectangle

Note that in both of these patterns, the solid ring around the sound port is still present; this ring is needed to ground the microphone and

for acoustic performance. The pad on the package connected to this ring is ground and still needs a solid electrical connection to the PCB

ground. If a pattern like one of these two examples is used on a PCB, take care that the unconnected rectangle on the bottom of the

INMP621 is not placed directly over any exposed copper. This ring on the microphone is still at ground, and any PCB traces routed

underneath it must be properly masked to avoid short circuits.

PCB MATERIAL AND THICKNESS

The performance of the INMP621 is not affected by PCB thickness and can be mounted on either a rigid or flexible PCB. A flexible

PCB with the microphone can be attached directly to the device housing with an adhesive layer. This mounting method offers a reliable

seal around the sound port, while providing the shortest acoustic path for good sound quality.

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Document Number: DS-INMP621-00

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INMP621

HANDLING INSTRUCTIONS

PICK AND PLACE EQUIPMENT

The MEMS microphone can be handled using standard pick-and-place and chip shooting equipment. Take care to avoid damage to the

MEMS microphone structure as follows:

• Use a standard pickup tool to handle the microphone. Because the microphone hole is on the bottom of the package, the

pickup tool can make contact with any part of the lid surface.

• Do not pick up the microphone with a vacuum tool that makes contact with the bottom side of the microphone.

Do not pull air out of or blow air into the microphone port.

• Do not use excessive force to place the microphone on the PCB.

REFLOW SOLDER

For best results, the soldering profile must be in accordance with the recommendations of the manufacturer of the solder paste used to

attach the MEMS microphone to the PCB. It is recommended that the solder reflow profile not exceed the limit conditions specified in

Figure 2 and Table 4.

BOARD WASH

When washing the PCB, ensure that water does not make contact with the microphone port. Do not use blow-off procedures or

ultrasonic cleaning.

Page 18 of 21

Document Number: DS-INMP621-00

Revision: 1.1

Rev Date: 05/21/2014

INMP621

OUTLINE DIMENSIONS

Figure 20. 5-Terminal Chip Array Small Outline No Lead Cavity [LGA_CAV]

4 mm × 3 mm Body

Dimensions shown in millimeters

Figure 21. Package Marking Specification (Top View)

04-19-2012-G

1.50

2.80

BOTTOM VIEW

TOP VIEW

SIDE VIEW

REFERENCE

CORNER

4.10

4.00

3.90

3.10

3.00

2.90

1 2 3

0.90

2.48

REF

0.72 REF

3.54 REF

1.05 REF

2.05

3.80

0.70

0.30 REF 0.25 DI A.

(T HRU HOLE )

1.10 DI A.

R 0.10 ( 2 ×)

1.70 DI A.

0.95 REF

0.35 0.35

0.30 REF

1.10

1.00

0.90

0.24 REF

0.40 × 0. 60

(Pins 1, 2, 4, 5)

0.30 REF

PIN 1

YY XXXX

621

LOT TRACEABILITY CODE

PIN 1 INDICATIONPART NUMBER

DATE CODE

Page 19 of 21

Document Number: DS-INMP621-00

Revision: 1.1

Rev Date: 05/21/2014

INMP621

ORDERING GUIDE

PART1

TEMP RANGE

PACKAGE

QUANTITY

INMP621ACEZ-R0*

−40°C to +85°C

5-Terminal LGA_CAV

5,000

INMP621ACEZ-R7†

−40°C to +85°C

5-Terminal LGA_CAV

1,000

EV_INMP621-FX

—

Flexible Evaluation Board

—

* – 13” Tape and Reel

† – 7” Tape and reel is to be discontinued. Check with sales@invensense.com for availability.

1Z = RoHS Compliant Part

REVISION HISTORY

REVISION DATE REVISION DESCRIPTION

02/06/2014 1.0 Initial Release

05/21/2014 1.1 Updated Compliance Disclaimer

Page 20 of 21

Document Number: DS-INMP621-00

Revision: 1.1

Rev Date: 05/21/2014

INMP621

COMPLIANCE DECLARATION DISCLAIMER

InvenSense believes the environmental and other compliance information given in this document to be correct but cannot

guarantee accuracy or completeness. Conformity documents substantiating the specifications and component characteristics are on

file. InvenSense subcontracts manufacturing and the information contained herein is based on data received from vendors and

suppliers, which has not been validated by InvenSense.

This information furnished by InvenSense is believed to be accurate and reliable. However, no responsibility is assumed by

InvenSense for its use, or for any infringements of patents or other rights of third parties that may result from its use. Specifications

are subject to change without notice. InvenSense reserves the right to make changes to this product, including its circuits and

software, in order to improve its design and/or performance, without prior notice. InvenSense makes no warranties, neither

expressed nor implied, regarding the information and specifications contained in this document. InvenSense assumes no

responsibility for any claims or damages arising from information contained in this document, or from the use of products and

services detailed therein. This includes, but is not limited to, claims or damages based on the infringement of patents, copyrights,

mask work and/or other intellectual property rights.

Certain intellectual property owned by InvenSense and described in this document is patent protected. No license is granted by

implication or otherwise under any patent or patent rights of InvenSense. This publication supersedes and replaces all information

previously supplied. Trademarks that are registered trademarks are the property of their respective companies. InvenSense sensors

should not be used or sold in the development, storage, production or utilization of any conventional or mass-destructive weapons

or for any other weapons or life threatening applications, as well as in any other life critical applications such as medical equipment,

transportation, aerospace and nuclear instruments, undersea equipment, power plant equipment, disaster prevention and crime

prevention equipment.

MotionApps, DMP, AAR, and the InvenSense logo are trademarks of InvenSense, Inc. Other company and product names may be

trademarks of the respective companies with which they are associated.

Page 21 of 21

Document Number: DS-INMP621-00

Revision: 1.1

Rev Date: 05/21/2014