The EL5129 and EL5329 integrate multiple gamma buffers with a single VCOM buffer for the use of large LCD panels of 10" and larger displays. The EL5129 integrates 6 gamma channels and the EL5329 integrates 10 gamma channels. The gamma One half of each device in the channel is designed to swing to the upper supply line, with the other half designed to swing to the lower rail. The output capability of each channel is 10mA continuous, with a 120mA peak. Gamma buffers are equipped with has a -3dB bandwidth specification of 10MHz and a slew rate of 9V/µs. The VCOM amplifier is designed to swing rails. The output current capability of the VCOM in the EL5129 and EL5329 is 30mA continuous, 150mA peak current and 10V/µs slew rate

The EL5129 and EL5329 use a high-voltage CMOS process. They have rail-to-rail input and output capability and very low power consumption. When driving a 10K and 12pF load, the buffer has a -3dB bandwidth of 10MHz and exhibits a 9V/µs slew rate. The VCOM amplifier has a 10V/µs slew rate of 12MHz and exhibits a -3dB bandwidth.

block diagram

Input, output and supply voltage ranges

The EL5129 and EL5329 are specified with a single nominal supply voltage from 5V to 15V or a split supply with a total range of 5V to 15V. Correct operation is guaranteed with a supply voltage range of 4.5V to 16.5V. The input common-mode voltage range of the EL5129 is 500mV beyond the power rails of the EL5329. The output buffers and the fluctuations of the V COM amplifier typically extend to a current of 5mA within a 100mV load with the positive and negative supply rails. Reducing the load current will expand the output voltage closer to each supply rail.

output phase reversal

The EL5129 and EL5329 are immune to inversion as long as the input voltage is not limited from V S--0.5V to VS++0.5V. Although the output of the device will not change phase, overvoltages of the input should be avoided. If the input voltage exceeds the supply voltage by more than 0.6V, ESD protection diodes placed on the input stage device begin to perform and overvoltage damage may occur.

output drive capability

The EL5129 and EL5329 do not have an internal short circuit protection circuit. The buffer will limit the short circuit current to ±120mA and the VCOM amplifier will limit the short circuit current to ±170mA if the output is shorted directly to the positive or negative supply. If the output is shorted indefinitely, the power dissipation can easily increase such that the part will be destroyed. Maximum reliability is maintained when the output continuous current never exceeds the ±15mA buffer and ±100mA current in the VCOM amplifier. These constraints are set by the design of the internal metal interconnects.

Power consumption

With the high output drive capability of the EL5129 and the EL5329, it is possible to exceed the 125°C "absolute-maximum junction temperature" condition at a certain load current. Therefore, it is very important to calculate the maximum junction temperature for the application to determine the load conditions that need to be modified for the buffer to remain within the safe operating area.

board layout

As with any high frequency device, good printed circuit board layout is necessary for optimum performance. Ground plane construction is strongly recommended, lead lengths should be kept as short as possible, and power pins must be well bypassed to reduce the risk of oscillation. For ordinary single-supply operation, where the VS- pin is grounded, a 0.1µF ceramic capacitor should be placed from the VS+ pin to ground. A 4.7µF tantalum capacitor should then be connected from the V S+ pin to ground. A 4.7µF capacitor can be used in a variety of devices. This same capacitor combination should be placed between each power supply pin and ground if separate power supplies are used. IMPORTANT: A metal plate for heat dissipation The unit is electrically connected to the negative supply potential (VS-). If VS- is connected to ground, the thermal pad can be connected to ground. Otherwise, the thermal pad must be isolated from any other power plane.

EL5129 pin diagram

EL5329 pin diagram