My Inquiry
My Account
Texas Instruments LM7705MMX/NOPB
- Part No.:
- LM7705MMX/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
- Datasheet:
-
LM7705MMX/NOPB.pdf
- Description:
- IC REG CHARGE PUMP -0.23V 8VSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:4,098
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
LM7705MMX/NOPB from Texas Instruments is a low-noise switched-capacitor negative bias generator delivering a regulated −0.232 V output with 5% tolerance, 4 mVPP ripple, and up to 98% conversion efficiency across 3 V–5.25 V input. It enables true-zero output operation in single-supply amplifiers by supplying a small negative rail without exceeding amplifier absolute maximum ratings.
For engineers reviewing the LM7705MMX/NOPB datasheet, LM7705MMX/NOPB pinout, LM7705MMX/NOPB application, or LM7705MMX/NOPB equivalent, key selection criteria include its fixed −0.232 V output voltage, 78 µA quiescent current, 20 nA shutdown current, 500 µs turnon time, and compatibility with rail-to-rail op amps requiring sub-50 mV saturation margin.
Technical Context
The LM7705MMX/NOPB integrates a pre-regulator, charge-pump inverter (91–92 kHz oscillator), and post-regulator to generate a stable −0.232 V output from a single positive supply. Its architecture uses two external capacitors-CFLY for charge transfer and CRES for reserve storage-to achieve low-noise inversion without inductors.
It operates in two functional modes: active (SD = LOW) with regulated output and shutdown (SD = HIGH) with output pulled to ground. Load regulation is 0.14%/mA and line regulation is 0.29%/V, ensuring stability across temperature (−40°C to 125°C) and supply variation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | −0.232 V ±5% - precisely calibrated to enable true-zero amplifier output without violating op amp VSS abs max ratings |
| Supply Range | 3 V to 5.25 V - compatible with common logic rails (3.3 V, 5 V) and supports battery-powered instrumentation |
| Output Ripple | 4 mVPP at −20 mA - low enough to avoid noise coupling into precision analog signal chains |
| Quiescent Current | 78 µA at 3.3 V - enables ultra-low-power operation in portable and always-on sensor front-ends |
| Shutdown Current | 20 nA - reduces standby power by >3,000×, critical for energy-harvesting and battery-life-critical systems |
| Turnon Time | 500 µs at 3.3 V - fast enough for periodic wake-up architectures without compromising settling accuracy |
| Efficiency | 98% at −5 mA - minimizes heat generation and input supply loading in space-constrained PCB layouts |
Pinout & Package
LM7705MMX/NOPB is housed in an 8-pin VSSOP package (3.00 mm × 3.00 mm body size) with exposed thermal pad for enhanced thermal performance in high-density analog designs.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CF+ | CFLY capacitor positive terminal | Connects to flying capacitor anode; timing and charge transfer depend on CFLY value (5 µF typical) |
| VSS | Power ground | Dual ground pins (2 & 5) reduce ground loop impedance and improve PSRR in sensitive analog sections |
| SD | Shutdown control input | Active-low logic interface; drives device ON when ≤1.25 V (−40°C to 125°C), OFF when ≥2.15 V |
| VDD | Positive supply input | Accepts 3 V–5.25 V; internal pre-regulator ensures stable operation across input variation |
| VOUT | Negative regulated output | Delivers −0.232 V to amplifier negative supply pin; low output impedance (0.26 Ω typ) maintains regulation under load |
| CRES | Reserve capacitor connection | Stabilizes post-regulated output; 22 µF recommended to minimize ripple and improve transient response |
| CF− | CFLY capacitor negative terminal | Completes charge-pump switching path; paired with CF+ to form bidirectional flying capacitor network |
Key Features
| Feature | Design Value |
|---|---|
| Fixed −0.232 V output | Eliminates need for external feedback resistors or trimming; guarantees consistent zero-reference across production lots |
| Low-noise regulation | 4 mVPP ripple ensures minimal error injection into precision amplifier stages and ADC reference paths |
| Single-supply operation | Enables true-zero amplifier outputs using only +V and GND-no dual supplies or discrete charge pumps required |
| Thermal robustness | Rated for −40°C to 125°C ambient; junction-to-ambient RθJA = 253°C/W supports reliable operation in industrial enclosures |
| Fast shutdown recovery | 500 µs turnon time allows dynamic power gating in multi-channel data acquisition systems without latency penalties |
Applications
| Portable Instrumentation | Low-Voltage Split-Power Supplies |
|---|---|
|
Use Scenario: Battery-powered handheld multimeters and sensor nodes requiring DC-coupled signal conditioning with full ADC range utilization. IC Role / Device Role / Timing Role: Provides −0.232 V bias to rail-to-rail op amps (e.g., LMP7701), enabling true-zero output swing from 0 V to VREF. Use Value: Recovers ~400 lost ADC quantization levels in 12-bit systems by eliminating amplifier output saturation at ground. |
Use Scenario: Space-constrained IoT edge nodes needing isolated negative bias for analog front-end ICs without inductor-based DC/DC converters. IC Role / Device Role / Timing Role: Generates compact, low-EMI negative rail using only ceramic capacitors-no magnetics or layout-sensitive inductors. Use Value: Reduces BOM count and PCB area vs. inductive inverters while maintaining <5 mV ripple at 20 mA load. |
| True Zero Amplifier Outputs | High-Accuracy Sensor Signal Chains |
|
Use Scenario: Single-supply medical sensors (e.g., ECG, pH) where amplifier output must reach exact 0 V to preserve DC integrity. IC Role / Device Role / Timing Role: Supplies stabilized −0.232 V to op amp VEE, lowering effective saturation voltage below 10 mV without exceeding 5.5 V total supply differential. Use Value: Prevents error accumulation in cascaded gain stages by eliminating offset amplification from first-stage saturation. |
Use Scenario: Precision weigh scales and strain-gauge bridges requiring 24-bit sigma-delta ADCs with zero-referenced inputs. IC Role / Device Role / Timing Role: Delivers ultra-low-noise negative bias to instrumentation amplifiers (e.g., INA333), improving common-mode rejection at DC. Use Value: Enables full-scale utilization of ADC input range while maintaining <0.01% gain error over temperature. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar negative bias generator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX1682ASA+ | Generates −2.5 V (not −0.232 V); higher quiescent current (120 µA); no integrated post-regulator | Suitable for general-purpose negative rails but cannot enable true-zero amplifier outputs without additional level-shifting | Select LM7705MMX/NOPB when precise −0.232 V is required to avoid op amp rail violations; MAX1682ASA+ only if higher negative voltage suffices |
| TPS60403DBVR | Adjustable output (−1.5 V to −5.5 V via resistor divider); 10 µA quiescent current; 200 µs turnon time | Requires external feedback components; lacks factory-trimmed fixed −0.232 V accuracy and low-noise post-regulation | Choose LM7705MMX/NOPB for plug-and-play true-zero operation; TPS60403DBVR only if programmability and lower IQ outweigh calibration complexity |
Compared with MAX1682ASA+ and TPS60403DBVR, LM7705MMX/NOPB uniquely delivers factory-trimmed −0.232 V with integrated post-regulation, enabling direct replacement of dual supplies in amplifier biasing-without design iteration, external resistors, or compromise on noise or accuracy.
Availability
LM7705MMX/NOPB is available at Aetrix Electronics and suitable for portable instrumentation, low-voltage split-power supplies, and true zero amplifier outputs requiring stable component supply across automotive, industrial, and medical product lifecycles.
Supply support for LM7705MMX/NOPB includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Texas Instruments is a global semiconductor company specializing in analog and embedded processing technologies, with leadership in precision analog, power management, and signal chain solutions.
LM7705MMX/NOPB belongs to TI's precision negative bias generator product line, designed specifically to solve true-zero output limitations in single-supply amplifier systems without requiring redesign or dual-rail infrastructure.
FAQ
What is the primary function of the LM7705MMX/NOPB?
The LM7705MMX/NOPB is a low-noise switched-capacitor negative bias generator that produces a tightly regulated −0.232 V output from a single 3 V–5.25 V supply. Its core function is to enable true-zero output operation in rail-to-rail amplifiers by providing a small negative supply rail-eliminating output saturation errors without exceeding amplifier absolute maximum voltage ratings. This makes LM7705MMX/NOPB essential for precision DC-coupled signal chains.
How does the LM7705MMX/NOPB achieve low output ripple?
The LM7705MMX/NOPB achieves 4 mVPP output ripple through a three-stage architecture: a pre-regulator stabilizes the input, a 91–92 kHz charge-pump inverter transfers energy via external CFLY and CRES capacitors, and a post-regulator filters high-frequency switching artifacts. The integrated post-regulator-absent in most charge-pump ICs-is key to LM7705MMX/NOPB's low ripple performance, especially under dynamic loads up to −20 mA.
Can the LM7705MMX/NOPB be used with rail-to-rail op amps operating from 3.3 V?
Yes, the LM7705MMX/NOPB is explicitly designed for this use case. When paired with a 3.3 V single supply, it delivers −0.232 V to the op amp's negative rail, resulting in a total supply differential of 3.532 V-well within the 5.5 V maximum rating of devices like the LMP7701. This configuration allows the op amp output to swing to true 0 V, recovering lost ADC resolution and preventing error propagation in cascaded gain stages-exactly as specified for LM7705MMX/NOPB in TI's application documentation.
What external components are required for basic LM7705MMX/NOPB operation?
LM7705MMX/NOPB requires three external ceramic capacitors: a 5 µF flying capacitor (CFLY) between CF+ and CF−, a 22 µF reserve capacitor (CRES) between CRES and VSS, and a 22 µF output capacitor (COUT) between VOUT and VSS. No inductors, resistors, or feedback networks are needed-LM7705MMX/NOPB's fixed −0.232 V output is internally trimmed and regulated, making it a truly plug-and-play solution for true-zero biasing.
Does the LM7705MMX/NOPB support thermal shutdown or overcurrent protection?
No, the LM7705MMX/NOPB does not include thermal shutdown or overcurrent protection circuitry. Its design relies on inherent current-limiting behavior of the charge-pump topology and safe operating area defined by absolute maximum ratings (e.g., 5.75 V VDD–VSS, 150°C junction temperature). Protection must be implemented externally-such as input current limiting or board-level thermal monitoring-if operating near limits. This simplifies the IC but places responsibility for system-level robustness on the designer, as documented in the LM7705MMX/NOPB datasheet.
LM7705MMX/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Negative
- Topology:
- Charge Pump
- Output Type:
- Fixed
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 3V
- Voltage - Input (Max):
- 5.25V
- Voltage - Output (Min/Fixed):
- -0.23V
- Voltage - Output (Max):
- -
- Current - Output:
- 26mA
- Frequency - Switching:
- 92kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-VSSOP
LM7705MMX/NOPB FAQ
1.How can I place an order for LM7705MMX/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM7705MMX/NOPB on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for LM7705MMX/NOPB reliable?
The price and inventory of LM7705MMX/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM7705MMX/NOPB is usually 5 days.
3.What payment methods are accepted for LM7705MMX/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM7705MMX/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM7705MMX/NOPB?
LM7705MMX/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM7705MMX/NOPB order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for LM7705MMX/NOPB?
For technical support, including LM7705MMX/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM7705MMX/NOPB requirements.
6.How does Aetrix verify that LM7705MMX/NOPB is sourced from the original manufacturer or authorized distributors?
All LM7705MMX/NOPB products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that LM7705MMX/NOPB meets industry standards.
7.What is the process for return or replacement of LM7705MMX/NOPB?
All LM7705MMX/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM7705MMX/NOPB, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The LM7705MMX/NOPB part is unused and in its original packaging.
Return procedure for LM7705MMX/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LM7705MMX/NOPB Tags
-
TPS562201DDCR
Texas Instruments
-
MC34063ABD-TR
STMicroelectronics
-
TPS561201DDCR
Texas Instruments
-
MC33063ADR
Texas Instruments
-
MC34063ADR
Texas Instruments
-
TPS560200DBVR
Texas Instruments
-
AP3012KTR-G1
Diodes Incorporated
-
TLV61048DBVR
Texas Instruments
-
AZ34063UMTR-G1
Diodes Incorporated
-
TPS562200DDCR
Texas Instruments
-
AP62300TWU-7
Diodes Incorporated
-
MC34063EBD-TR
STMicroelectronics
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
