PMIC - Voltage Reference

Part Number	Description / PDF	Quantity
MAX6129AEUK30+T Maxim Integrated	IC VREF SERIES 0.4% SOT23-5	5000
MAX6126A25+T Maxim Integrated	IC VREF SERIES 0.06% 8UMAX	956
MAX6033BAUT41+T Maxim Integrated	ULTRA-HIGH-PRECISION SOT23 SERIE	0
MAX6126A28+T Maxim Integrated	IC VREF SERIES 0.06% 8UMAX	0
MAX6023EBT21+T Maxim Integrated	IC VREF SERIES 0.2% 5UCSP	0
MAX6126B30+ Maxim Integrated	IC VREF SERIES 0.1% 8UMAX	1089800
MAX8069ESA+ Maxim Integrated	IC VREF SHUNT 2.4% 8SOIC	122928500
MAX6350CPA+ Maxim Integrated	IC VREF SERIES 0.02% 8DIP	85
MAX6126BASA30+ Maxim Integrated	IC VREF SERIES 0.06% 8SOIC	602
MAX6143BASA10+ Maxim Integrated	IC VREF SERIES 0.1% 8SOIC	2300
MAX6250BCSA+T Maxim Integrated	IC VREF SERIES 0.1% 8SOIC	476
MAX6071AAUT33+T Maxim Integrated	IC VREF SERIES 0.04% SOT23-6	0
MAX6126A21+ Maxim Integrated	IC VREF SERIES 0.06% 8UMAX	289
LM4040CEM3-4.1+T Maxim Integrated	IC VREF SHUNT 0.5% SOT23-3	217535000
MAX6341ESA+ Maxim Integrated	IC VREF SERIES 0.02% 8SOIC	2001300
MAX6325ESA+ Maxim Integrated	IC VREF SERIES 0.04% 8SOIC	3092900
MAX6241BEPA+ Maxim Integrated	IC VREF SERIES 0.1% 8DIP	108700
MAX6071AAUT21+T Maxim Integrated	IC VREF SERIES 0.04% SOT23-6	37932500
MAX6037BAUK12+T Maxim Integrated	IC VREF SERIES 0.3% SOT23-5	200015000
LM4040BIM3-2.5/V+T Maxim Integrated	IC VREF SHUNT 0.2% SOT23-3	65000

PMIC - Voltage Reference

1. Overview

Voltage references are precision analog circuits that generate stable and accurate DC voltage levels. As critical components in Power Management Integrated Circuits (PMICs), they serve as calibration standards for analog-to-digital converters (ADCs), digital-to-analog converters (DACs), and power monitoring systems. Their stability against temperature variations, process shifts, and supply voltage fluctuations ensures measurement accuracy and system reliability in modern electronics.

2. Main Types and Functional Classification

Type	Functional Features	Application Examples
Bandgap Reference	Temperature-compensated design using bipolar transistor characteristics	General-purpose ADC/DAC calibration
Zener Reference	High-voltage stability through reverse breakdown characteristics	Industrial power supplies, test equipment
LDO Voltage Reference	Low dropout voltage with high PSRR performance	Battery-powered devices, portable instruments
High-Precision Reference	Sub-0.1% initial accuracy with ppm-level temperature drift	Medical imaging systems, precision sensors
Programmable Reference	Digital control of output voltage via I2C/SPI interfaces	Adaptive power systems, FPGA voltage scaling

3. Structure and Composition

Typical voltage reference architecture includes: - Primary reference source (bandgap or Zener diode) - Operational amplifier for voltage buffering - Temperature compensation circuitry - Output driver stage - Protective elements (ESD protection, current limiting) Fabricated using CMOS/BiCMOS processes, housed in SC70, SOT23, or TSSOP packages with 3-8 pins. Advanced designs integrate digital calibration registers and thermal shutdown functions.

4. Key Technical Specifications

Parameter	Description	Importance
Initial Accuracy	Voltage deviation at 25 C ( 0.02% to 1%)	Determines system calibration baseline
Temperature Coefficient	Drift rate over temperature range (1-100ppm/ C)	Affects measurement stability
Output Noise	RMS noise voltage in 0.1-10Hz band (5 V to 100 V)	Impacts ADC/DAC resolution
Load Regulation	Voltage change with load current (0.01%/mA)	Ensures stability under dynamic loads
Line Regulation	Voltage change with supply voltage (0.05%/V)	Maintains accuracy with supply variations

5. Application Areas

Communication: 5G base stations, optical transceivers, RF test equipment
Consumer: Smartphones, wearables, battery management systems
Industrial: Process control sensors, PLC modules, precision instrumentation
Automotive: Battery management systems (BMS), ADAS sensors, engine controllers
Medical: MRI systems, portable diagnostic devices, patient monitors

6. Leading Manufacturers and Products

Manufacturer	Product Series	Key Features
TI	LM4040/LM4050	0.1% accuracy, 50ppm/ C tempco, 50mA output
Analog Devices	ADR45xx	0.02% initial accuracy, 3ppm/ C drift
Maxim Integrated	MAX6126	Series voltage reference with enable pin
STMicroelectronics	LN3480	Low-power consumption (380nA IQ)
ON Semiconductor	NCP100	Cost-effective solution for 12-bit ADCs

7. Selection Guidelines

Key selection criteria: - Required accuracy class (0.02% vs 1%) - Operating temperature range (-55 C to +125 C) - Power supply constraints (voltage headroom, quiescent current) - Package size and thermal dissipation capability - Long-term stability requirements (aging effects) - Cost vs performance trade-offs (e.g., programmable vs fixed) Example: For a 16-bit industrial ADC system, select a reference with <5ppm/ C tempco and <1 Vpp noise.

8. Industry Trends

Nanometer process integration enabling sub-1V references
Development of chopper-stabilized references for ultra-low drift
Increase in digital programmable references with I2C interfaces
Advancements in radiation-hardened references for aerospace
Reduced package sizes (0.65mm x 1.0mm WLCSP)
AI-enhanced self-calibration algorithms in smart references