TJ7660D

The TJ7660 performs supply voltage conversions from positive to negative for an input range of +1.5V to +10.0V resulting in complementary output voltages of -1.5V to -10.0V. Only 2 noncritical external capacitors are needed for the charge pump and charge reservoir functions. The TJ7660 can also be connected to function as voltage doublers and will generate output voltages up to +18.6V with a +10V input. Contained on the chip are a series DC supply regulator, RC oscillator, voltage level translator, and four output power MOS switches. A unique logic element senses the most negative voltage in the device and ensures that the output N-Channel switch source-substrate junctions are not forward biased. This assures latchup free operation. The oscillator, when unloaded, oscillates at a nominal frequency of 10kHz for an input supply voltage of 5.0V. This frequency can be lowered by the addition of an external capacitor to the “OSC” terminal, or the oscillator may be overdriven by an external clock. The “LV” terminal may be tied to GROUND to bypass the internal series regulator and improve low voltage (LV) operation. At medium to high voltages (+3.5V to +10.0V for the TJ7660), the LV pin is left floating to prevent device latchup.

Applications

• On Board Negative Supply for Dynamic RAMs
• Localized µProcessor (8080 Type) Negative Supplies
• Inexpensive Negative Supplies
• Data Acquisition Systems

Key features

• Simple Conversion of +5V Logic Supply to ±5V Supplies
• Simple Voltage Multiplication (VOUT = (-)nVIN)
• Typical Open Circuit Voltage Conversion Efficiency 99.9%
• Typical Power Efficiency 98%
• Wide Operating Voltage Range - TJ7660 1.5V to 10.0V
• Easy to Use - Requires Only 2 External Non-Critical Passive Components
• No External Diode Over Full Temp. and Voltage Range
• Moisture Sensitivity Level 3