LM4851ITLX/NOPB National Semiconductor, LM4851ITLX/NOPB Datasheet - Page 13

• Manufacturer Part Number: LM4851ITLX/NOPB
• Description: IC AMP AUDIO PWR 1.5W AB 18USMD
• Manufacturer: National Semiconductor
• Series: Boomer®r
• Type: Class ABr

Specifications of LM4851ITLX/NOPB

• Output Type: 1-Channel (Mono) with Stereo Headphones
• Max Output Power X Channels @ Load: 1.5W x 1 @ 4 Ohms; 115mW x 2 @ 32 Ohms
• Voltage - Supply: 2.6 V ~ 5 V
• Features: Depop, Shutdown, SPI, Thermal Protection, Volume Control
• Mounting Type: Surface Mount
• Package / Case: 18-MicroSMD
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: LM4851ITLX

Application Information
SPI PIN DESCRIPTION
DATA: This is the serial data input pin.
CLK: This is the clock input pin.
ENB: This is the SPI enable pin and is active-high.
SPI OPERATION DESCRIPTION
The serial data bits are organized into a field which contains
8 bits of data defined by TABLE 1. The Data 0 to Data 2 bits
determine the output mode of the LM4851 as shown in
TABLE 2. The Data 3 to Data 7 bits determine the volume
level setting as illustrated by TABLE 3. For each SPI transfer,
the data bits are written to the DATA pin with the least
significant bit (LSB) first. All serial data are sampled at the
rising edge of the CLK signal. Once all the data bits have
been sampled, ENB transitions from logic-high to logic-low
to complete the SPI sequence. All 8 bits must be received
before any data latch can occur. Any excess CLK and DATA
transitions will be ignored after the eighth rising clock edge
P = Phone In
R = Rin
L = Lin
SD = Shutdown
G = Gain of volume control
Default Mode upon device power-up is Output Mode 0
Output Mode #
0
1
2
3
4
5
6
7
Data 2
0
0
0
0
1
1
1
1
Data 1
0
0
1
1
0
0
1
1
TABLE 2. Output Mode Selection
Data 0
0
1
0
1
0
1
0
1
13
has occurred. For any data sequence longer than 8 bits, only
the first 8 bits will get loaded into the shift register and the
rest of the bits will be disregarded.
G(R+L) + 6dB x P
SPKR
6dB x P
6dB x P
G(R+L)
SD
SD
SD
SD
Data 0
Data 1
Data 2
Data 3
Data 4
Data 5
Data 6
Data 7
OUT
TABLE 1. Bit Allocation
(G x R) + P
(G x R) + P
G x R
R
SD
SD
SD
SD
OUT
P
Volume 1
Volume 2
Volume 3
Volume 4
Volume 5
Mode 1
Mode 2
Mode 3
(G x L) + P
(G x L) + P
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G x L
L
SD
SD
SD
SD
OUT
P