LMV1088RL/NOPB National Semiconductor, LMV1088RL/NOPB Datasheet - Page 18

• Manufacturer Part Number: LMV1088RL/NOPB
• Description: IC AMP AUDIO MONO AB MIC 36USMD
• Manufacturer: National Semiconductor
• Series: PowerWise®r
• Type: Class ABr

Specifications of LMV1088RL/NOPB

• Output Type: 1-Channel (Mono)
• Voltage - Supply: 2.7 V ~ 5.5 V
• Features: Differential Inputs, I²C, Microphone, Mute
• Mounting Type: Surface Mount
• Package / Case: 36-MicroSMDxt
• Amplifier Class: AB
• No. Of Channels: 2
• Supply Voltage Range: 2.7V To 5.5V
• Load Impedance: 10kohm
• Operating Temperature Range: -40°C To +85°C
• Amplifier Case Style: SMD
• No. Of Pins: 36
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Max Output Power X Channels @ Load: -
• Other names: LMV1088RLTR

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PERFORMING A THREE TONE CALIBRATION
In a system with two microphones in an enclosure there will
always be a difference in the transfer function in both gain and
frequency response. The LMV1088 has the capability to per-
form an automatic calibration function to minimize these dif-
ferences. To perform this calibration, a test sequence of three
tones is required right after the PE and CAL inputs are brought
to a logic high level. At the end of this sequence the calibration
data is automatically stored in the internal EEPROM.
The three tones have to be applied as follows:
•
NOTE: Data guaranteed by design
A first tone with a frequency of 1kHz
Symbol
t
t
t
t
t
t
t
ST1
ET1
ST2
ET2
ST3
ET3
CC
Calibration Start Tone 1
Calibration End Tone 1
Calibration Start Tone 2
Calibration End Tone 2
Calibration Start Tone 3
Calibration End Tone 3
Calibration Complete
TABLE 5. Automatic Calibration Timing Parameters
Parameter
FIGURE 8. Three Tone Calibration Timing
18
•
•
A tone may be applied prior to the rising of CAL and PE. Sig-
nals applied to the microphone inputs before rising of CAL
and PE are ignored by the calibration system. .
Between each tone pair there is a small time, indicated by a
cross, to change the frequency. During that time the input tone
is ignored by the calibration system.
The total calibration sequence requires less then 770ms.
A second tone with a frequency of 300Hz
A third tone with a frequency of 3kHz
Min
200
400
600
770
Limits
Max
215
415
10
202130r3
Unitis
ms
ms
ms
ms
ms
ms
ms