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LM7705

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Low Noise Negative Bias Generator

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Data sheet

LM7705

ACTIVE
Data sheet Order now

Product details

Vin (Min) (V) 3 Vin (Max) (V) 5.25 Vout (Min) (V) -0.232 Vout (Max) (V) -0.232 Iout (Max) (A) 0.026 Regulated outputs (#) 1 Switching frequency (Min) (kHz) 92 Switching frequency (Max) (kHz) 92 Iq (Typ) (mA) 0.078 Features Enable, Synchronous Rectification Rating Catalog
Vin (Min) (V) 3 Vin (Max) (V) 5.25 Vout (Min) (V) -0.232 Vout (Max) (V) -0.232 Iout (Max) (A) 0.026 Regulated outputs (#) 1 Switching frequency (Min) (kHz) 92 Switching frequency (Max) (kHz) 92 Iq (Typ) (mA) 0.078 Features Enable, Synchronous Rectification Rating Catalog
VSSOP (DGK) 8 15 mm² 3 x 4.9
  • Regulated Output Voltage −0.232 V
  • Output Voltage Tolerance 5%
  • Output Voltage Ripple 4 mVPP
  • Supply Voltage 3 V to 5.25 V
  • Conversion Efficiency Up to 98%
  • Quiescent Current 78 µA
  • Shutdown Current 20 nA
  • Turnon Time 500 µs
  • Operating Temperature Range −40°C to 125°C
  • 8-Pin VSSOP Package
  • Regulated Output Voltage −0.232 V
  • Output Voltage Tolerance 5%
  • Output Voltage Ripple 4 mVPP
  • Supply Voltage 3 V to 5.25 V
  • Conversion Efficiency Up to 98%
  • Quiescent Current 78 µA
  • Shutdown Current 20 nA
  • Turnon Time 500 µs
  • Operating Temperature Range −40°C to 125°C
  • 8-Pin VSSOP Package

The LM7705 device is a switched capacitor voltage inverter with a low noise, −0.23 V fixed negative voltage regulator. This device is designed to be used with low voltage amplifiers to enable the amplifiers output to swing to zero volts. The −0.23 V is used to supply the negative supply pin of an amplifier while maintaining less then 5.5 V across the amplifier. Rail-to-Rail output amplifiers cannot output zero volts when operating from a single-supply voltage and can result in error accumulation due to amplifier output saturation voltage being amplified by following gain stages. A small negative supply voltage will prevent the amplifiers output from saturating at zero volts and will help maintain an accurate zero through a signal processing chain. Additionally, when an amplifier is used to drive an input of the ADC, the amplifier can output a zero voltage signal and the full input range of an ADC can be used. The LM7705 device has a shutdown pin to minimize standby power consumption.

The LM7705 device is a switched capacitor voltage inverter with a low noise, −0.23 V fixed negative voltage regulator. This device is designed to be used with low voltage amplifiers to enable the amplifiers output to swing to zero volts. The −0.23 V is used to supply the negative supply pin of an amplifier while maintaining less then 5.5 V across the amplifier. Rail-to-Rail output amplifiers cannot output zero volts when operating from a single-supply voltage and can result in error accumulation due to amplifier output saturation voltage being amplified by following gain stages. A small negative supply voltage will prevent the amplifiers output from saturating at zero volts and will help maintain an accurate zero through a signal processing chain. Additionally, when an amplifier is used to drive an input of the ADC, the amplifier can output a zero voltage signal and the full input range of an ADC can be used. The LM7705 device has a shutdown pin to minimize standby power consumption.
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* Data sheet LM7705 Low-Noise Negative Bias Generator datasheet (Rev. D) PDF | HTML 08 May 2018
Application note Quick Reference Guide To TI Buck Switching DC/DC Application Notes (Rev. B) PDF | HTML 23 May 2022
Technical article How to achieve microvoltage-level precision in thermopile applications 09 Dec 2021
Circuit design Charge pump circuit (–0.3V) for negative amplifier supply 16 Jun 2019
Application note Attenuator Amplifier Design to Maximize the Input Voltage of Differential ADCs 14 Jun 2018
Technical article Unique active mux capability combines buffer and switch into one solution 10 Oct 2017
Technical article Where did the op amp ground pin go? 18 Mar 2016
Technical article Painting a picture for powering high-performance FPGAs 05 Sep 2013
EVM User's guide AN-1883 LM7705 Evaluation Board (Rev. B) 03 May 2013

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