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onsemi MC33680FTBR2
- Part No.:
- MC33680FTBR2
- Manufacturer:
- onsemi
- Package:
- 32-LQFP
- Datasheet:
-
MC33680FTBR2.pdf
- Description:
- IC REG BOOST ADJ DL 32LQFP
- Quantity:
- Payment:
- Shipping:
Inventory:1,099
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Product details
Overview
MC33680FTBR2 from onsemi is a dual DC-DC regulator IC for handheld electronic organizers, integrating a main PFM boost regulator (adjustable 2.7–5 V, 200 mA max at 1.8 V input) and an auxiliary PFM boost regulator (5–25 V, 25 mA @5 V / 15 mA @25 V), both featuring synchronous rectification (main) or built-in BJT (aux), low-startup voltage (1 V), and supervisory functions including low-battery detection, Power-Good signal, and lithium/supercap backup control.
For engineers reviewing the MC33680FTBR2 datasheet, pinout, applications, or equivalent options, key selection considerations include dual-output programmability, battery-backed operation from 1–2 AA/AAA cells, integrated supervision logic, and LQFP-32 package compatibility with space-constrained portable designs.
Technical Context
The MC33680FTBR2 implements Pulse-Frequency-Modulation (PFM) on both regulators to maintain high efficiency at light loads, with fixed ON-time control and current-limit protection. The main regulator uses an internal synchronous rectifier FET (M2) with dead-time management to prevent shoot-through, while the auxiliary regulator employs an integrated power BJT with external Schottky diode rectification.
Supervisory circuitry includes a programmable Power-On Reset (PORB) with capacitor-defined delay (via PDELAY pin), hysteresis-based low-battery detection (0.85 V / 1.1 V thresholds), and microprocessor-controllable lithium backup switch (LIBATON/LIBATCL logic). All bias currents derive from a single precision VI converter (IREF pin), ensuring timing consistency across regulators.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Main Output Range | 2.7 V to 5.0 V, adjustable via external resistor divider on VMAINFB pin; nominal 3.3 V @ 100 mA with 1.8 V input |
| Auxiliary Output Range | +5 V to +25 V, set by external potentiometer between VAUXFBP/VAUXFBN; supports LCD contrast voltage generation |
| Startup Voltage | 1.0 V minimum, enabling operation from single-cell alkaline or NiMH batteries without pre-charge |
| Quiescent Current | 35 μA typical in standby mode, critical for extending battery life in always-on organizer applications |
| Efficiency | 87% at 60 mA load for main regulator; auxiliary efficiency ranges 50–75% depending on VIN and IOUT per Figures 6–11 |
| Package | 32-pin LQFP (Case 873A), 7 mm × 7 mm footprint with 0.8 mm pitch, suitable for compact PCB layouts |
| Operating Temp | 0 °C to +70 °C ambient, validated for consumer handheld device environments |
Pinout & Package
MC33680FTBR2 is housed in a 32-lead LQFP package (Case 873A), with exposed thermal pad not electrically connected. Pin assignments follow standard top-view orientation as defined in Figure 1 of the datasheet.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VMAINFB | Feedback Input | Resistor-divider node for main output voltage regulation; referenced to internal 1.22 V bandgap |
| VBAT (pins 2,3) | Main Supply Input | Primary battery input (1–2 AA/AAA); powers both regulators and internal logic |
| VDD | Internal Logic Supply | Decoupled output for internal bias circuits; requires local 20 μF capacitor |
| PDELAY | POR Timing Control | Capacitor connection defining Power-On Reset delay (TPOR = 1.22 × Cpor × RIref) |
| LOWBATSEN | Battery Threshold Sense | Resistive divider input setting low-battery detection hysteresis (0.85 V / 1.1 V) |
| PORB | Power-Good Output | Active-low reset signal asserting when VMAIN reaches (VMAIN_set − 0.15 V) |
| LIBATON / LIBATCL | Backup Switch Control | Dual-input logic enabling microprocessor or autonomous control of lithium backup path |
| VAUXEN | Auxiliary Enable | Active-high digital input enabling/disabling the auxiliary regulator independently |
| VAUXFBP / VAUXFBN | Aux Feedback Inputs | Differential feedback pair setting VAUX output via RAUXa/RAUXb ratio (VAUX = VREF × (1 + RAUXb/RAUXa)) |
| VMAINSW / VAUXSW | Switch Node Outputs | Inductor connection points for main (synchronous FET) and auxiliary (BJT collector) switching stages |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent PFM regulators | Enables simultaneous generation of logic supply (3.3 V) and LCD bias (e.g., 15 V), eliminating need for discrete boost stages |
| Synchronous rectification (main) | Reduces conduction loss vs. Schottky diode, achieving 87% efficiency at 60 mA without external MOSFET drivers |
| Programmable Power-On Reset | External capacitor on PDELAY pin sets PORB assertion delay (e.g., 100 ms with 100 nF), synchronizing MCU startup with stable VMAIN |
| Hysteresis-based battery monitoring | Configurable low-battery threshold (0.85 V / 1.1 V) prevents oscillation during gradual discharge of alkaline cells |
| Lithium backup switch control | On-chip 13 Ω switch with dual-mode logic (auto or MCU-controlled) maintains RTC/memory during main battery removal |
Applications
| Digital Organizer Power System | Handheld MPU/Memory Supply |
|---|---|
Use Scenario: Powering a palm-sized electronic dictionary with LCD display, flash memory, and ARM7 processor. IC Role / Device Role / Timing Role: MC33680FTBR2 serves as the primary power management IC, generating 3.3 V for MPU/core logic and 15 V for LCD contrast adjustment. Use Value: Single-chip solution eliminates discrete DC-DC converters and supervisor ICs, reducing BOM count by ≥4 components and PCB area by 35%. | Use Scenario: Battery-powered PDA requiring stable dual-rail supply under variable load (idle vs. active display/USB). IC Role / Device Role / Timing Role: MC33680FTBR2 delivers regulated 3.3 V (main) and 5 V (aux) while managing low-battery warning and backup switchover. Use Value: PFM operation maintains >80% efficiency down to 100 μA load, extending runtime by 2.1× versus PWM alternatives in standby. |
| LCD Contrast Voltage Generator | Low-Voltage Backup Power System |
Use Scenario: Adjustable contrast control for monochrome STN LCD in portable medical thermometer. IC Role / Device Role / Timing Role: MC33680FTBR2 auxiliary regulator configured as 8–12 V adjustable source, driven by potentiometer on VAUXFBP/FBN pins. Use Value: Eliminates need for external op-amp DAC + boost converter; achieves <1% output drift over temperature via bandgap-referenced feedback. | Use Scenario: Maintaining SRAM and real-time clock during battery replacement in industrial data logger. IC Role / Device Role / Timing Role: MC33680FTBR2's integrated lithium backup switch activates automatically when main VBAT drops below LIBATIN −100 mV. Use Value: On-die 13 Ω switch reduces backup path resistance by 60% vs. discrete MOSFET solutions, minimizing voltage drop and preserving data integrity. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-output DC-DC regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX1702EASA+ | Single 3.3 V/5 V dual-output boost; no auxiliary high-voltage capability; no integrated battery backup switch | Lacks 5–25 V programmable auxiliary output and lithium backup control logic | Select when only logic-rail generation is needed and external supervision is acceptable |
| TPS65130RGER | Integrated 3.3 V + ±15 V dual-output; higher quiescent current (100 μA); no low-startup (min 2.7 V input) | Cannot operate from single 1.5 V cell; lacks programmable POR delay and battery hysteresis | Prefer for systems with Li-ion input and need for negative rail; avoid for alkaline/NiMH primary cells |
Compared with MAX1702EASA+ and TPS65130RGER, the MC33680FTBR2 uniquely combines ultra-low startup voltage (1 V), wide auxiliary output range (5–25 V), and on-chip lithium backup switching-making it irreplaceable for cost-sensitive, battery-only handhelds requiring both logic and display bias rails.
Availability
MC33680FTBR2 is available at Aetrix Electronics and suitable for digital organizers, handheld PDAs, and portable medical devices requiring stable component supply with long-term lifecycle support.
Supply support for MC33680FTBR2 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
onsemi (formerly ON Semiconductor) is a global semiconductor supplier specializing in energy-efficient power management, analog, and sensor technologies for automotive, industrial, and portable electronics.
The MC33680FTBR2 belongs to onsemi's portable power management product line, engineered specifically for single-cell battery-powered handheld devices needing integrated dual-output regulation and system supervision.
FAQ
What is the minimum input voltage required for MC33680FTBR2 to start regulating?
The MC33680FTBR2 has a guaranteed startup voltage of 1.0 V, allowing reliable operation from a single discharged AA/AAA alkaline or NiMH cell. This is achieved through optimized internal biasing and low-threshold comparators, enabling full functionality even as battery voltage declines below 1.2 V during end-of-life conditions. The MC33680FTBR2 maintains regulation down to this threshold without external assist circuitry.
How is the main output voltage adjusted on MC33680FTBR2?
The main output voltage of the MC33680FTBR2 is set using an external resistor divider connected to the VMAINFB pin. With the internal reference at 1.22 V, VMAIN = 1.22 V × (1 + RMAINb / RIref), where RIref is typically 480 kΩ. Adjusting RMAINb changes the output linearly from 2.7 V to 5.0 V; for example, RMAINb = 1.0 MΩ yields ~3.3 V. The MC33680FTBR2 datasheet provides exact calculation examples in Section 9.
Does MC33680FTBR2 support independent enable control for each regulator?
Yes, the MC33680FTBR2 provides independent enable control: the main regulator starts automatically upon VBAT application, while the auxiliary regulator is controlled via the VAUXEN pin (active-high CMOS input). This allows dynamic power sequencing-e.g., enabling the 3.3 V rail first for MCU boot, then activating the 15 V LCD bias only when display content is rendered. The MC33680FTBR2 does not require external logic to coordinate this sequence.
What protection features are integrated into MC33680FTBR2?
The MC33680FTBR2 integrates current-limit protection on both regulators (ILIM_VM = 1.0 A typ, ILIM_VL = 1.0 A), thermal shutdown (Tj(max) = 150 °C), and output overvoltage clamping via internal zener structures. It also includes undervoltage lockout (UVLO) tied to VBAT, disabling regulation if input falls below 0.8 V. These protections are fully autonomous-no external components or configuration are required for basic fault coverage. The MC33680FTBR2 implements them using on-die sense FETs and comparators.
Can MC33680FTBR2 drive a 25 V load at full rated current?
The MC33680FTBR2 supports 25 V auxiliary output, but only at reduced current: 15 mA maximum with 1.8 V input (per datasheet Section 5, "STATIC ELECTRICAL CHARACTERISTICS"). At higher input voltages (e.g., 3.0 V), output current capability increases due to greater energy transfer per cycle. However, efficiency drops significantly above 20 V (Figure 7 shows ~55% at 25 V/15 mA), so thermal design must account for >150 mW dissipation in the VAUX BJT. The MC33680FTBR2 is optimized for 5–15 V auxiliary use cases.
MC33680FTBR2 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- 32-LQFP
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Function:
- Step-Up
- Output Configuration:
- Positive
- Topology:
- Boost
- Output Type:
- Adjustable
- Number of Outputs:
- 2
- Voltage - Input (Min):
- 1V
- Voltage - Input (Max):
- 7V, 30V
- Voltage - Output (Min/Fixed):
- 2.7V, 5V
- Voltage - Output (Max):
- 5V, 25V
- Current - Output:
- -
- Frequency - Switching:
- 100kHz, 120kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 32-LQFP (7x7)
MC33680FTBR2 FAQ
1.How can I place an order for MC33680FTBR2 through Aetrix?
Please submit a Request for Quotation (RFQ) for MC33680FTBR2 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 MC33680FTBR2 reliable?
The price and inventory of MC33680FTBR2 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MC33680FTBR2 is usually 5 days.
3.What payment methods are accepted for MC33680FTBR2?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MC33680FTBR2 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MC33680FTBR2?
MC33680FTBR2 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MC33680FTBR2 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 MC33680FTBR2?
For technical support, including MC33680FTBR2 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MC33680FTBR2 requirements.
6.How does Aetrix verify that MC33680FTBR2 is sourced from the original manufacturer or authorized distributors?
All MC33680FTBR2 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 MC33680FTBR2 meets industry standards.
7.What is the process for return or replacement of MC33680FTBR2?
All MC33680FTBR2 units undergo pre-shipment inspection (PSI). If there is an issue with MC33680FTBR2, 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 MC33680FTBR2 part is unused and in its original packaging.
Return procedure for MC33680FTBR2:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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