PMIC - Voltage Reference

Part Number	Description / PDF	Quantity
REF2925AIDBZT Texas Instruments	IC VREF SERIES 2% SOT23-3	1360
LM4041C12IDCKRE4 Texas Instruments	IC VREF SHUNT 0.5% SC70-5	0
REF4132B30DBVRQ1 Texas Instruments	AUTOMOTIVE 12-PPM/C LOW-NOISE LO	2995
LM385LPRE3-1-2 Texas Instruments	IC VREF SHUNT 2% TO92-3	1998
LM4040AIM3-2.5 Texas Instruments	MICROPOWER SHUNT VOLTAGE REF	9215
LM4140CCM-1.0/NOPB Texas Instruments	IC VREF SERIES 0.1% 8SOIC	697
TL4050B50QDBZR Texas Instruments	TL4050B PRECISION MICROPOWER SHU	21044
LT1004ID-1-2 Texas Instruments	IC VREF SHUNT 0.32% 8SOIC	2801
LM4051AIM3-ADJ/NOPB Texas Instruments	IC VREF SHUNT 10V 0.1% SOT23-3	893
LM4040C50IDBZR Texas Instruments	IC VREF SHUNT 0.5% SOT23-3	64
REF6030IDGKR Texas Instruments	IC VREF SERIES 0.05% 8VSSOP	0
LM4128AMFX-3.3/NOPB Texas Instruments	IC VREF SERIES 0.1% SOT23-5	0
LM285BXZ/NOPB Texas Instruments	IC VREF SHUNT 5.3V 1% TO92-3	51
LM385M/NOPB Texas Instruments	IC VREF SHUNT 5.3V 2% 8SOIC	3276
TL4051A12QDBZT Texas Instruments	IC VREF SHUNT 0.1% SOT23-3	240
LM4128BMFX-3.3/NOPB Texas Instruments	LM4128 SOT-23 PRECISION MICROPOW	3000
LM4040CIM3-10.0 Texas Instruments	IC VREF SHUNT 0.5% SOT23-3	936
TL431CLP Texas Instruments	3 TERMINAL VOLTAGE REFERENCE	68295
LT1009IPWR Texas Instruments	IC VREF SHUNT 0.4% 8TSSOP	0
LM4041D12QDBZT Texas Instruments	TWO TERMINAL VOLTAGE REFERENCE	6250

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