Overview
The LM828M5X-NS, produced by National Semiconductor (now part of Texas Instruments), is a CMOS charge-pump voltage converter. This device is designed to invert a positive input voltage in the range of +1.8V to +5.5V to the corresponding negative voltage of −1.8V to −5.5V. It operates at a 12 kHz switching frequency and uses two external capacitors to achieve this voltage conversion. The LM828 is particularly suited for battery-powered systems due to its high efficiency and low operating current.
Key Specifications
| Parameter | Min | Typ | Max | Units |
|---|---|---|---|---|
| Supply Voltage (V+ to GND) | 1.8 | 5.5 | V | |
| Continuous Output Current | 50 | mA | ||
| Output Short-Circuit Duration to GND | 1 | sec | ||
| Continuous Power Dissipation (TA = 25°C) | 240 | mW | ||
| Operating Junction Temperature Range | −40 | 85 | °C | |
| Storage Temperature Range | −65 | 150 | °C | |
| Lead Temperature (Soldering, 10 seconds) | 300 | °C | ||
| ESD Rating | 2kV | |||
| Supply Current (No Load) | 40 | 75 | 115 | μA |
| Output Resistance (IL = 5 mA) | 20 | 65 | Ω | |
| Oscillator Frequency | 12 | 24 | kHz | |
| Switching Frequency | 6 | 28 | kHz | |
| Power Efficiency (IL = 5 mA) | 97 | % |
Key Features
- Inverts input supply voltage from +1.8V to +5.5V to the corresponding negative voltage of −1.8V to −5.5V.
- Operates in a tiny SOT-23 package.
- Typical output impedance of 20Ω.
- Provides up to 25 mA of output current.
- High conversion efficiency, typically 97% at 5 mA load.
- Low operating current of 40 μA (typical) with no load.
- 12 kHz switching frequency to reduce output resistance and voltage ripple.
Applications
- Cellular Phones
- Pagers
- PDAs
- Operational Amplifier Power Supplies
- Interface Power Supplies
- Handheld Instruments
Q & A
- What is the primary function of the LM828? The LM828 is a CMOS charge-pump voltage converter that inverts a positive input voltage to a corresponding negative voltage.
- What is the input voltage range for the LM828? The input voltage range is from +1.8V to +5.5V.
- What is the typical output current of the LM828? The LM828 can provide up to 25 mA of output current.
- What is the switching frequency of the LM828? The switching frequency is 12 kHz.
- What is the typical conversion efficiency of the LM828? The typical conversion efficiency is 97% at a 5 mA load.
- What is the operating current of the LM828 with no load? The operating current is typically 40 μA with no load.
- In what package is the LM828 available? The LM828 is available in a SOT-23 package.
- What are some common applications of the LM828? Common applications include cellular phones, pagers, PDAs, operational amplifier power supplies, interface power supplies, and handheld instruments.
- Is the LM828 still in production? No, the LM828 has been discontinued by Texas Instruments.
- What is the maximum continuous output current of the LM828? The maximum continuous output current is 50 mA.
