LM48557TLEVAL National Semiconductor, LM48557TLEVAL Datasheet - Page 13

• Manufacturer Part Number: LM48557TLEVAL
• Description: BOARD EVALUATION LM48557
• Manufacturer: National Semiconductor
• Series: Boomer®r

Specifications of LM48557TLEVAL

• Amplifier Type: Class AB
• Output Type: 1-Channel (Mono)
• Voltage - Supply: 2.7 V ~ 4.5 V
• Operating Temperature: -40°C ~ 85°C
• Board Type: Fully Populated
• Utilized Ic / Part: LM48557
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Max Output Power X Channels @ Load: -

SINGLE AND MULTI-BYTE WRITE OPERATION
The LM48557 supports both single-byte and multi-byte write
operations. A single-byte write operation begins with the mas-
ter device transmitting a START condition followed by the
device address (Figure 7). After receiving the correct device
address, the LM48557 generates an ACK bit. The master de-
vice transmits the register data byte, after which the LM48557
generates and ACK bit. Following the ACK, the master issues
a STOP condition, completing the singly-byte data transfer.
A multi-byte write operation is similar to a single-byte opera-
tion, the master device issues a START condition and device
GENERAL AMPLIFIER FUNCTION
The LM48557 is a fully differential ceramic speaker driver that
utilizes National’s inverting charge pump technology to deliv-
er over 5.8V
from a single 4.2V supply. The low noise, inverting charge
pump generates a negative supply voltage (CPV
RMS
to a 1µF ceramic speaker while operating
FIGURE 7. Single-Byte Write Example
FIGURE 8. Multi-Byte Write Example
SS
) from the
13
address, and the LM48557 responds with an ACK (Figure 8).
The master device then transmits the first data byte. Following
the LM48557’s ACK, the master device does not issue a
STOP condition, transmitting a second data byte instead. The
LM48557 responds with an ACK bit. The master device can
continue to issue data bytes, and the LM48557 will respond
with an ACK, until a STOP condition is issued. Once a STOP
condition is issued, the LM48557 ignores the I
master issues the LM48557’s device address.
positive supply voltage (PV
tage of the increased head room created by the charge pump
and the bridge-tied load (BTL) architecture, delivering signif-
icantly more voltage than a single-ended, single-supply am-
plifier to the speaker.
DD
). The LM48557 takes advan-
2
C bus until the
30098109
www.national.com
30098105