LTC3260EMSE

Part: LTC3260EMSE — Linear Technology (now Analog Devices)

Type: Low Noise Dual Supply Inverting Charge Pump

Description: The LTC3260 is a low noise dual polarity output power supply that includes an inverting charge pump with both positive and negative LDO regulators, operating over a 4.5V to 32V input range and delivering up to 100mA of output current from the charge pump, with each LDO providing up to 50mA.

Operating Conditions:

• Supply voltage: 4.5–32 V
• Operating temperature: -40 to 125 °C (suffix-dependent — see Order Information for grade-specific ranges)
• Oscillator frequency: 50kHz to 500kHz (programmable)

Absolute Maximum Ratings:

• Max supply voltage: 36 V
• Max continuous current: 250 mA (VOUT Short-Circuit Current)
• Max junction/storage temperature: 150 °C

Key Specs:

• Input Voltage Range: 4.5 V to 32 V
• V IN Quiescent Current (Burst Mode, both LDOs on, I VOUT = 0mA): 100 μA (typ)
• Charge Pump Output Current (Max I VOUT Short-Circuit Current): 100 mA (min)
• Positive LDO Output Current (LDO + Short-Circuit Current): 50 mA (min)
• Negative LDO Output Current (LDO - Short-Circuit Current): 50 mA (min)
• Oscillator Frequency (RT = GND): 500 kHz (typ)
• LDO + Dropout Voltage (I LDO + = 50mA): 400 mV (typ)
• LDO - Dropout Voltage (I LDO - = 50mA): 200 mV (typ)
• LDO Output Voltage Noise (C BYP = 10nF): 100 μV RMS (typ)

Features:

• Inverting Charge Pump Generates -V IN
• Low Noise Negative LDO Post Regulator (I LDO - = 50mA Max)
• Low Noise Independent Positive LDO Regulator (I LDO + = 50mA Max)
• 100μA Quiescent Current in Burst Mode Operation with Both LDO Regulators On
• 50kHz to 500kHz Programmable Oscillator Frequency
• Stable with Ceramic Capacitors
• Short-Circuit/Thermal Protection

Applications:

• Low Noise Bipolar/Inverting Supplies
• Industrial/Instrumentation Low Noise Bias Generators
• Portable Medical Equipment
• Portable Instruments

Package:

• 14-Lead (4mm × 3mm) Plastic DFN
• 16-Lead Plastic MSOP

• n VIN Range: 4.5V to 32V
• n Inverting Charge Pump Generates -V IN
• n Charge Pump Output Current Up to 100mA
• n Low Noise Negative LDO Post Regulator (I LDO - = 50mA Max)
• n Low Noise Independent Positive LDO Regulator (I LDO + = 50mA Max)
• n 100μA Quiescent Current in Burst Mode ® Operation with Both LDO Regulators On
• n 50kHz to 500kHz Programmable Oscillator Frequency
• n Stable with Ceramic Capacitors
• n Short-Circuit/Thermal Protection
• n Low Profile 3mm × 4mm 14-Pin DFN and Thermally Enhanced 16-Pin MSOP Packages

• n Low Noise Bipolar/Inverting Supplies
• n Industrial/Instrumentation Low Noise Bias Generators
• n Portable Medical Equipment
• n Portable Instruments

Note 1: Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. Exposure to any Absolute Maximum Rating condition for extended periods may affect device reliability and lifetime.

these specifications is determined by specific operating conditions in conjunction with board layout, the rated package thermal impedance and other environmental factors.

Note 2: The LTC3260 is tested under pulsed load conditions such that T J ≈ T A . The LTC3260E is guaranteed to meet specifications from 0°C to 85°C junction temperature. Specifications over the -40°C to 125°C operating junction temperature range are assured by design, characterization and correlation with statistical process controls. The LTC3260I is guaranteed over the -40°C to 125°C operating junction temperature range, the LTC3260H is guaranteed over the -40°C to 150°C operating junction temperature range and the LTC3260MP is tested and guaranteed over the full -55°C to 150°C operating junction temperature range. Note that the maximum ambient temperature consistent with

The junction temperature (T J , in °C) is calculated from the ambient temperature (T A , in °C) and power dissipation (P D , in Watts) according to the formula:

where θ JA = 43°C/W is the package thermal impedance.

Note 3: This IC includes overtemperature protection that is intended to protect the device during momentary overload conditions. Junction temperatures will exceed 150°C when overtemperature protection is active. Continuous operation above the specified maximum operating junction temperature may result in device degradation or failure.

The LTC3260 has built-in short-circuit current limit as well as overtemperature protection. During a short-circuit condition, the part automatically limits its output current to approximately 160mA. If the junction temperature exceeds approximately 175°C the thermal shutdown circuitry disables current delivery to the output. Once the junction temperature drops back to approximately 165°C current delivery to the output is resumed. When thermal protection is active the junction temperature is beyond the specified operating range. Thermal protection is intended for momentary overload conditions outside normal operation. Continuous operation above the specified maximum operating junction temperature may impair device reliability.

Low Noise ±12V Power Supply from a Single-Ended 15V Input Supply (Frequency = 200kHz)