SSM2380CBZ-REEL Analog Devices Inc, SSM2380CBZ-REEL Datasheet - Page 17

• Manufacturer Part Number: SSM2380CBZ-REEL
• Description: Stereo ClassD Amplifier I2C Gain Control
• Manufacturer: Analog Devices Inc
• Type: Class Dr

Specifications of SSM2380CBZ-REEL

• Output Type: 2-Channel (Stereo)
• Max Output Power X Channels @ Load: 3.2W x 2 @ 4 Ohm
• Voltage - Supply: 2.5 V ~ 5.5 V
• Features: Depop, Differential Inputs, I²C, Mute, Short-Circuit and Thermal Protection
• Mounting Type: Surface Mount
• Package / Case: 16-UFBGA, WLCSP
• Operational Class: Class-D
• Audio Amplifier Output Configuration: 2-Channel Stereo
• Audio Amplifier Function: Speaker
• Single Supply Voltage (typ): 3/5V
• Power Supply Requirement: Single
• Rail/rail I/o Type: No
• Power Supply Rejection Ratio: 85dB
• Single Supply Voltage (min): 2.5V
• Single Supply Voltage (max): 5.5V
• Operating Temp Range: -40C to 85C
• Operating Temperature Classification: Industrial
• Mounting: Surface Mount
• Pin Count: 16
• Package Type: WLCSP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Attack Time, Hold Time, and Release Time
When the amplifier input signal exceeds a preset threshold,
the ALC reduces amplifier gain rapidly until the output voltage
settles to a target level. This target level is maintained for a certain
period. If the input voltage does not exceed the threshold again,
the ALC increases the gain gradually.
The attack time is the time taken to reduce the gain from maxi-
mum to minimum. The hold time is the time that the reduced
gain is maintained. The release time is the time taken to increase
the gain from minimum to maximum. These times are shown
in Table 9.
Table 9. Attack, Hold, and Release Times for I
Time
Attack Time
Hold Time
Release Time
1
Soft-Knee Compression
Often performed using sophisticated DSP algorithms, soft-knee
compression provides maximum sound quality with effective
speaker protection. Instead of using a fixed compression setting
prior to limiting, the SSM2380 allows for a much more subtle
transition into limiting mode, preserving the original sound
quality of the source audio. Figure 38 to Figure 40 show the
various soft-knee compression settings. If desired, compression
can be disabled. When compression is disabled, the part operates
in limiter-only mode.
The attack time and release time can be adjusted using the I
The hold time cannot be adjusted.
1
2.5
2.0
1.5
1.0
0.5
0
0
Figure 38. Adjustable Compression Settings, V
0.05
0.10
ALC Threshold Level = 77%
0.15
INPUT VOLTAGE (V)
Duration
32 μs to 4 ms (per 0.5 dB step)
90 ms to 120 ms
4 ms to 512 ms (per 0.5 dB step)
0.20
0.25
00 (LIMITER MODE)
01 (COMPRESSION MODE 1)
10 (COMPRESSION MODE 2)
11 (COMPRESSION MODE 3)
2.5V × 0.77 = 1.925V
0.30 0.35
2
0.40
C Control Mode
DD
= 2.5 V,
2
0.45
C interface.
0.50
Rev. A | Page 17 of 32
ALC Soft Transition
The ALC operation of the SSM2380 incorporates techniques to
reduce the audible artifacts associated with gain change transi-
tions. First, the gain is changed in small increments of 0.5 dB.
In addition to this small step size, the rate of gain change is
reduced, proportional to the attack time setting. This feature
drastically reduces and virtually eliminates the presence of zipper
noise and other artifacts associated with gain transitions during
ALC operation. Figure 41 shows the soft transition operation.
3.5
3.0
2.5
2.0
1.5
1.0
0.5
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0
0
Figure 39. Adjustable Compression Settings, V
0
0
Figure 40. Adjustable Compression Setting, V
0.1
0.2
SOFT TRANSITION (32µs TO 256µs)
0.2
0.4
NORMAL TRANSITION
ALC Threshold Level = 77%
ALC Threshold Level = 77%
Figure 41. Soft Transition
0.3
0.6
INPUT VOLTAGE (V)
INPUT VOLTAGE (V)
0.4
0.8
0.5
1.0
00 (LIMITER MODE)
01 (COMPRESSION MODE 1)
10 (COMPRESSION MODE 2)
11 (COMPRESSION MODE 3)
3.6V × 0.77 = 2.772V
00 (LIMITER MODE)
01 (COMPRESSION MODE 1)
10 (COMPRESSION MODE 2)
11 (COMPRESSION MODE 3)
5.0V × 0.77 = 3.85V
0.6
1.2
0.7
1.4
0.8
1.6
DD
DD
0.5dB
0.5dB
= 5.0 V,
= 3.6 V,
SSM2380
0.9
1.8
1.0
2.0