Sharp LC-37D90U Service Manual page 37

2.2. VHiTA2024++-1Y (ASSY: IC2303)
STEREO DIGITAL AUDIO AMPLIFIER
• Block Diagram [VHiTA2024++-1Y (ASSY: IC2303)]
• Pin Function [VHiTA2024++-1Y (ASSY: IC2303)]
Pin No. Pin Name
2,3 DCAP2,
DCAP1
4,9 V5D, V5A
5,8,17 AGND1,
AGND2,
AGND3
6 REF
7 OVERLOADB
10,14 OAOUT1,
OAOUT2
11,15 INV1,
INV2
12 MUTE
16 BIASCAP
18 SLEEP
19 FAULT
20,35 PGND2,
PGND1
22 DGND
24,27, OUTP2 & OUTM2,
31,28 OUTP1 & OUTM1
25,26, VDD2,VDD2,
29,30 VDD1,VDD1
13,21,23, NC
32,34
33 VDDA
36 CPUMP
1 5VGEN
I/O
Charge pump switching pins. DCAP1 (pin 3) is a free running 300kHz square wave between
VDDA and DGND (12Vpp nominal). DCAP2 (pin 2) is level shifted 10 volts above DCAP1 (pin 3)
with the same amplitude (12Vpp nominal), frequency, and phase as DCAP1.
--- Digital 5VDC, Analog 5VDC.
--- Analog Ground.
--- Internal reference voltage; approximately 1.0 VDC.
A logic low output indicates the input signal has overloaded the amplifier.
O Input stage output pins.
Single-ended inputs. Inputs are a "virtual" ground of an inverting opamp with approximately
2.4VDC bias.
When set to logic high, both amplifiers are muted and in idle mode. When low (grounded), both
amplifiers are fully operational. If left floating, the device stays in the mute mode. This pin should
be tied to GND if not used.
Input stage bias voltage (approximately 2.4VDC).
When set to logic high, device goes into low power mode. If not used, this pin should be
grounded.
A logic high output indicates thermal overload, or an output is shorted to ground, or another out-
put.
--- Power Grounds (high current).
--- Digital Ground. Connect to AGND locally (near the TA2024).
O Bridged output pairs.
Supply pins for high current H-bridges, nominally 12VDC.
--- Not connected. Not bonded internally.
--- Analog 12VDC.
Charge pump output (nominally 10V above VDDA).
Regulated 5VDC source used to supply power to the input section (pins 4 and 9).
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Pin Function
LC-37D90U