The LA7840 is a field deflection output integrated circuit manufactured by Sanyo. It features a DC-coupled input design, which allows for direct signal transmission without the need for coupling capacitors. This IC is commonly used in television systems where it amplifies the field sawtooth voltage generated by other control circuits like the LA76810, enabling it to drive the field deflection coil directly. Internally, the LA7840 contains several key components, including an operational amplifier for generating the sawtooth voltage, an overheat protection circuit, and a pump power supply circuit. It operates with a low current of 1.8A in small-screen TVs, making it energy-efficient. The chip also offers minimal crossover distortion, uses a single power supply, and has a simple structure with few external components required, which makes it ideal for cost-effective designs. This measurement was conducted on a Hisense TC2199A TV using an MF10B multimeter, with the resistance measured in the R×1k range. The data provides useful information for troubleshooting or understanding the internal functionality of the LA7840 IC in real-world applications. Laptop Stands And Risers,Laptop Riser Computer Laptop Stand,Laptop Folding Table Stand Aluminum,Laptop Stand Portable Aluminum Laptop Riser Shenzhen ChengRong Technology Co.,Ltd. , https://www.laptopstandsupplier.com
Pin Number
Label
Features
Voltage (V)
Resistance to Ground (kΩ)
Black Pen Grounding
Red Pen Grounding
1
GND
Ground
0
0
0
2
V OUT
Field scan output
12.5
1.0
1.0
3
VCC2
Pump power supply voltage input
24.8
6.3
&
4
NON-INV IN
Field sawtooth voltage input
2.5
2.2
2.5
5
INV IN
Inverting input
2.5
4.4
4.1
6
VCC
Voltage
24.3
6.3
18.5
7
PUMP UP
Pump power output
1.9
7.5
35