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Diodes Incorporated DDZ21Q-7
- Part No.:
- DDZ21Q-7
- Manufacturer:
- Diodes Incorporated
- Category:
- Single Zener Diodes
- Package:
- SOD-123
- Datasheet:
-
DDZ21Q-7.pdf
- Description:
- DIODE ZENER 21.18V 470MW SOD123
- Quantity:
- Payment:
- Shipping:
Inventory:9,125
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Product details
Overview
DDZ21Q-7 from Diodes Incorporated is a precision surface-mount Zener diode with nominal zener voltage 21.0 V (min 20.64 V, max 21.71 V), 5 mA test current, 30 Ω zener impedance at IZT, 0.05 µA reverse leakage at 17.0 V, and SOD123 package. It delivers tight voltage regulation for reference and protection circuits in power supply feedback loops, voltage clamping, and analog signal conditioning.
For engineers reviewing the DDZ21Q-7 datasheet, DDZ21Q-7 pinout, DDZ21Q-7 application, or DDZ21Q-7 equivalent, this page provides verified electrical parameters, thermal derating behavior, automotive qualification status (AEC-Q101), RoHS/Green compliance, and real-world use context for stable voltage reference design.
Technical Context
This device operates as a two-terminal voltage reference diode, conducting in reverse breakdown to maintain stable voltage across its terminals under controlled current. Its 21 V nominal zener voltage falls in the medium-voltage range where temperature coefficient crosses zero - confirmed by Fig. 18 showing TC ≈ +0.02 %/°C near 21 V.
Designed for high-precision applications, it features very tight VZ tolerance (±2.5% at 21 V), low dynamic impedance (30 Ω @ 5 mA), and guaranteed low leakage (≤0.05 µA @ 17 V). The SOD123 package enables automated placement while maintaining thermal resistance of 425 °C/W on minimal PCB copper.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 20.64–21.71 V @ IZT = 5 mA - defines stable reference point for feedback networks requiring ±2.5% accuracy |
| Zener Impedance (ZZT) | 30 Ω @ 5 mA - ensures minimal output voltage variation under load transients in regulation circuits |
| Reverse Leakage (IR) | ≤0.05 µA @ VR = 17.0 V - guarantees negligible error current in high-impedance reference paths |
| Power Dissipation | 294 mW @ TA = 25°C (min pad layout) - sets maximum continuous bias current to ~14 mA at 21 V |
| Thermal Resistance (RθJA) | 425 °C/W - requires careful thermal layout to avoid exceeding 150°C junction temperature in enclosed environments |
| Temperature Coefficient | +0.02 %/°C near 21 V (Fig. 18) - enables low-drift performance without external compensation in industrial temp range |
| Package | SOD123 - 2.65 mm × 1.55 mm footprint compatible with standard pick-and-place equipment and reflow profiles |
Pinout & Package
Two-terminal device in SOD123 package: cathode marked by band; anode unmarked. Terminals are matte tin annealed over Alloy 42 leadframe, solderable per MIL-STD-202 Method 208. Moisture sensitivity level 1 (J-STD-020).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Cathode (banded end) | Breakdown terminal | Connected to higher potential node in reverse-bias configuration; determines polarity of regulated voltage drop |
| Anode (unmarked end) | Reference terminal | Typically tied to circuit ground or common return; establishes 0 V reference for VZ measurement |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualified | Validated for automotive applications including engine control units and ADAS power rails requiring PPAP documentation |
| Tight VZ tolerance | ±2.5% at 21 V enables single-diode reference designs without trimming resistors in cost-sensitive systems |
| Green / Halogen-free | Meets <900 ppm Br, <900 ppm Cl, <1000 ppm Sb - satisfies automotive OEM chemical content requirements (e.g., GMW3172) |
| Low leakage current | 0.05 µA @ 17 V minimizes loading error in high-Z op-amp reference buffers and battery-monitoring inputs |
| Stable TC near zero | +0.02 %/°C at 21 V reduces drift to <±10 mV over –40°C to +125°C ambient in unregulated environments |
Applications
| Power Supply Feedback Reference | Overvoltage Clamp Protection |
|---|---|
|
Use Scenario: Regulating output voltage in isolated flyback converters using TL431-like feedback topology. IC Role / Device Role / Timing Role: Provides precise 21 V reference to optocoupler LED drive circuit, enabling accurate secondary-side voltage sensing. Use Value: Enables ±1% output regulation without auxiliary winding or digital calibration, reducing BOM count and layout area. |
Use Scenario: Protecting microcontroller I/O pins against ESD-induced voltage spikes on 18–24 V industrial bus lines. IC Role / Device Role / Timing Role: Acts as shunt clamp, diverting transient energy above 21 V to ground before reaching sensitive logic inputs. Use Value: Limits peak clamped voltage to ≤22.5 V (per VZ max + dynamic rise), staying within absolute maximum ratings of 3.3 V/5 V MCUs with level-shifting interface. |
| Analog Sensor Signal Conditioning | Automotive Battery Monitoring |
|
Use Scenario: Biasing precision instrumentation amplifiers in 4–20 mA transmitter modules operating from 24 V loop supply. IC Role / Device Role / Timing Role: Supplies stable 21 V rail to op-amp dual supplies via resistive divider and local decoupling. Use Value: Maintains amplifier PSRR >80 dB up to 10 kHz due to low ZZT, preventing supply noise coupling into low-level sensor signals. |
Use Scenario: Monitoring 24 V vehicle battery health in body control modules during cold-cranking (down to 6 V) and load-dump (up to 40 V). IC Role / Device Role / Timing Role: Serves as overvoltage threshold detector feeding comparator input; triggers fault flag when VBAT exceeds 21.7 V. Use Value: Detects alternator regulator failure with 0.3 V hysteresis margin below load-dump peak, avoiding false trips during normal transients. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener reference applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| BZX84-C21LT1G | Same 21 V nominal, but ±5% tolerance (vs. ±2.5%), 50 Ω ZZT, SOT-23 package | Higher impedance limits use in fast transient regulation; smaller SOT-23 footprint reduces thermal mass | Select if board space is constrained and ±5% accuracy suffices; avoid in precision feedback loops |
| MMSZ5248B-TP | 20 V nominal, ±5%, 22 Ω ZZT, SOD-123 - tighter impedance but lower voltage rating | Requires redesign of resistor dividers to match 21 V setpoint; better for low-noise analog references | Choose when lower dynamic impedance outweighs need for exact 21 V; verify TC shift at 20 V vs. 21 V |
Compared with BZX84-C21LT1G and MMSZ5248B-TP, DDZ21Q-7 offers superior voltage accuracy and automotive qualification - critical for safety-related monitoring and closed-loop power control where parameter drift directly impacts system stability.
Availability
DDZ21Q-7 is available at Aetrix Electronics and suitable for automotive ECUs, industrial power supplies, and battery management systems requiring stable component supply with full traceability and long-term lifecycle support.
Supply support for DDZ21Q-7 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
Diodes Incorporated is a global manufacturer of discrete semiconductors and analog ICs, specializing in high-reliability components for automotive, industrial, and computing markets.
The DDZ series targets precision voltage reference needs in cost-sensitive, high-volume applications - balancing tight tolerance, low leakage, and AEC-Q101 compliance for functional-safety-aware designs.
FAQ
Is DDZ21Q-7 suitable for automotive applications?
Yes - DDZ21Q-7 is AEC-Q101 qualified, PPAP capable, and manufactured in IATF16949 certified facilities. Its qualification covers temperature cycling, humidity testing, and mechanical shock per automotive reliability standards, making it appropriate for under-hood and chassis-mounted electronics.
What is the maximum continuous reverse current for stable operation?
At 25°C ambient with minimum PCB copper (Note 8), the device supports up to 14 mA continuous reverse current (294 mW ÷ 21 V) before exceeding its 294 mW power limit. Derating is required above 25°C per Figure 1 - e.g., 10 mA max at 75°C ambient.
How does the temperature coefficient affect accuracy over –40°C to +125°C?
Per Figure 18, TC is +0.02 %/°C near 21 V. Over 165°C range, total drift is ~3.3 mV/°C × 165°C = ±545 mV - i.e., VZ shifts from ~20.46 V to ~21.96 V. This remains within ±3% total deviation, supporting industrial-grade accuracy without active compensation.
Can DDZ21Q-7 replace DDZ21 without modification?
Yes - DDZ21Q-7 is the automotive-qualified variant of DDZ21, sharing identical electrical specs, SOD123 package, and marking code "ZK". The "Q" suffix denotes AEC-Q101 qualification and IATF16949 manufacturing; no schematic or layout changes are needed for drop-in replacement in automotive designs.
DDZ21Q-7 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Diodes Incorporated
- Series:
- -
- Package/Case:
- SOD-123
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Voltage - Zener (Nom) (Vz):
- 21.18 V
- Tolerance:
- ±3%
- Power - Max:
- 470 mW
- Impedance (Max) (Zzt):
- 30 Ohms
- Current - Reverse Leakage @ Vr:
- 50 nA @ 17 V
- Voltage - Forward (Vf) (Max) @ If:
- 900 mV @ 10 mA
- Operating Temperature:
- -65°C ~ 150°C
- Grade:
- Automotive
- Qualification:
- AEC-Q101
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOD-123
DDZ21Q-7 FAQ
1.How can I place an order for DDZ21Q-7 through Aetrix?
Please submit a Request for Quotation (RFQ) for DDZ21Q-7 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 DDZ21Q-7 reliable?
The price and inventory of DDZ21Q-7 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for DDZ21Q-7 is usually 5 days.
3.What payment methods are accepted for DDZ21Q-7?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for DDZ21Q-7 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for DDZ21Q-7?
DDZ21Q-7 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your DDZ21Q-7 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 DDZ21Q-7?
For technical support, including DDZ21Q-7 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your DDZ21Q-7 requirements.
6.How does Aetrix verify that DDZ21Q-7 is sourced from the original manufacturer or authorized distributors?
All DDZ21Q-7 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 DDZ21Q-7 meets industry standards.
7.What is the process for return or replacement of DDZ21Q-7?
All DDZ21Q-7 units undergo pre-shipment inspection (PSI). If there is an issue with DDZ21Q-7, 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 DDZ21Q-7 part is unused and in its original packaging.
Return procedure for DDZ21Q-7:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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