| Overview
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| Diagrams
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| Parametrics
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| Documents
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| Order
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| Packaging
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| Reliability
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Features
| • | I2C/SPI Control Interface |
| • | I2C/SPI programmable National 3D Audio |
| • | I2C/SPI controlled 32 step digital volume control (-54dB to +18dB) |
| • | Three independent volume channels (Left, Right, Mono) |
| • | Eight distinct output modes |
| • | microSMD surface mount packaging |
| • | "Click and Pop" suppression circuitry |
| • | Thermal shutdown protection |
| • | Low shutdown current (0.1uA, typ) |
Description The LM4845 is an audio power amplifier capable of delivering 500mW of continuous average power into a mono 8 bridged-tied load (BTL) with 1% THD+N, 25mW per channel of continuous average power into stereo 32 single-ended (SE) loads with 1% THD+N, or an output capacitor-less (OCL) configuration with identical specification as the SE configuration, from a 3.3V power supply.
The LM4845 features a 32-step digital volume control and eight distinct output modes. The digital volume control, 3D enhancement, and output modes (mono/SE/OCL) are programmed through a two-wire I2C or a three-wire SPI compatible interface that allows flexibility in routing and mixing audio channels. The LM4845 has three input channels: one pair for a two-channel stereo signal and the third for a single-channel mono input.
The LM4845 is designed for cellular phone, PDA, and other portable handheld applications. It delivers high quality output power from a surface-mount package and requires only seven external components in the OCL mode (two additional components in SE mode).
Key Specification
| THD+N at 1kHz, 500mW into 8 BTL (3.3V) | 1.0% (typ) |
| THD+N at 1kHz, 30mW into 32 SE (3.3V) | 1.0% (typ) |
| Single Supply Operation (VDD) | 2.7 to 5.5V |
| I2C/SPI Single Supply Operation | 2.2 to 5.5V |
Applications
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| Parameters | Values |
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| Power@ 4Ohms, 10% THD |
Undefined Watt |
| Power@ 4Ohms, 1% THD |
Undefined Watt |
| Power@ 8Ohms, 10% THD |
0.7 Watt |
| Power@ 8Ohms, 1% THD |
0.5 Watt |
| THD |
0.5 % |
| PSRR |
88 dB |
| SNR |
Undefined dB |
| Channels |
3 Channels |
| THD Conditions |
f=20Hz-20kHz,Pout=250mW,Rl=8phm,BTL,mode 1 |
| PSRR Conditions |
Vrpi=200mVpp,f=217Hz,Cb=2.2uF,SE,Co=100uF All inputs terminated |
| User Supply |
3.3 Volt |
| Audio Mux |
Yes |
| Capless Headphone |
Yes |
| ClassD Driver |
No |
| Interface |
I2C,SPI |
| Stereo Inputs |
1 |
| National 3D |
Yes |
| Digital Volume Control Max |
18 dB |
| Digital Volume Control Min |
-54 dB |
| Output Modes |
8 |
| Supply Range |
+2.7 - +5.5 V |
| Mono Inputs |
1 |
| Temperature Min |
-40 deg C |
| Temperature Max |
85 deg C |
| Loudspeaker Type |
Class AB |
| Headphone Type |
Virtual Ground |
| Loudspeaker Outputs |
1 |
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Datasheet
Featured Application Notes
More Application Notes
Part Number(s)
(NSID) | Top View | Availability | Current Reported Stock | Budgetary Pricing | Standard Pack Size |
|---|
LM4845ITL/NOPB
RoHS | | Full production
Lead Time: 6 weeks
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| $2.50 each at 1K+ pcs | reel
of
250 |
Reliability Metrics
| Part Number |
Process |
EFR Reject |
EFR Sample Size |
PPM |
LTA Rejects |
LTA Device Hours |
FITS |
MTTF (Hours) |
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LM4845ITL | CS065 | 2 | 38968 | 52 | 0 | 4402000 | 1 | 1249079519
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Note: The Early Failure Rates (EFR) were calculated as point estimate PPM based on rejects and sample size for EFR.
The Long Term Failure Rates were calculated
at 60% confidence using the Arrhenius equation at 0.7eV activation energy and derating the assumed stress
temperature of 150°C to an application temperature of 55°C.
For more information on Reliability Metrics, please click here.
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