LMV1088RL/NOPB National Semiconductor, LMV1088RL/NOPB Datasheet - Page 19

• 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

THREE TONE CALIBRATION SETUP
A calibration test setup consist of a test room (acoustical box)
with a loudspreaker (acoustical source) driven with the test
tone sequence from Figure 8. The test setup is shown in Fig-
ure 9. The distance between the source and microphone 1
and microphone 2 must be equal and the sound must travel
without any obstacle from source to both microphones.
SUPPLY CURRENT DURING CALIBRATION
The Calibration function performs two main tasks in a se-
quence. First the AC characteristics of the microphones are
matched. Then in the second stage, if the PE pin is high, the
on-chip EEPROM is programmed.
During the first stage of this sequence the supply current on
the LMV1088 will increase to about 2.5 mA. During the writing
of the EEPROM the supply current will rise for about 215ms
to about 30 mA. This increased current is used for the on chip
charge pump which generates the high voltages that are re-
quired for programming the EEPROM.
FIGURE 9. Three Tone Calibration Test setup
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The sound will travel with the limited speed of 300m/s from
the loudspeaker source to the microphones. When creating
the calibration signals this time should not be ignored, 30cm
distance will cause 1ms delay.
FIGURE 10. Supply current during calibration and
programming
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