CA-IS3221
Dual channel isolated gate driver with 5kVrms isolation, programmable dead time, and UVLO protection for
Product Overview
Description
CA-IS3221 is a dual channel isolated gate driver designed for half-bridge and synchronous buck topologies. The device features two independent gate drive channels with programmable dead time.
With 4A peak output current per channel and 5kVrms isolation, this driver is ideal for medium-power applications requiring reliable half-bridge drive.
The programmable dead time (via external resistor) prevents shoot-through, while UVLO protection ensures reliable operation during power transients.
Product Series
CA
Primary Application
Half-bridge converters
Key Features
- Dual channel half-bridge driver
- 5kVrms reinforced isolation
- 4A peak output per channel
- Programmable dead time
- Excellent channel matching <10ns
- UVLO protection on both sides
- Separate source/sink outputs
- AEC-Q100 qualified
Specifications
| Channels | 2 (half-bridge configuration) |
|---|---|
| Isolation Voltage | 5kVrms (reinforced) |
| Peak Output Current | 4A source/sink per channel |
| Programmable Dead Time | 100ns to 5μs |
| Propagation Delay | 80ns typical |
| Delay Matching | <10ns between channels |
| UVLO Threshold | 8V (VCC2) |
| Package | SOIC-16, QSOP-16 |
Applications
Half-bridge converters
Power conversion and supply
Synchronous buck converters
Power conversion and supply
Motor drives
Motor drive and control systems
DC-DC converters
Power conversion and supply
Inverters
Electronic system design
Power supplies
Electronic system design
LED drivers
Motor drive and control systems
FAE Expert Insights
"CA-IS3221 is an excellent choice for half-bridge applications up to several hundred watts. The programmable dead time is a key feature that allows optimization for different power devices. I've used this driver in DC-DC converter designs with switching frequencies up to 500kHz with excellent results. The channel matching (<10ns) ensures good dead time control even at high frequencies. The 4A peak current is sufficient for MOSFETs up to about 100A rating. For best performance, I recommend using the separate source/sink outputs with different resistors to optimize turn-on and turn-off speeds independently."
Programmable dead time with excellent channel matching
— Dr. Chen Wei, BeiLuo
Frequently Asked Questions
How do I set the dead time with CA-IS3221?
CA-IS3221 dead time is set by an external resistor (RDT) connected between DT pin and GND1. The dead time formula is: Tdead = (RDT × 0.5pF) + 100ns. For example: RDT = 100kΩ gives Tdead = 150ns; RDT = 1MΩ gives Tdead = 600ns; RDT = 10MΩ gives Tdead = 5.1μs. Select RDT based on your power device turn-off time plus safety margin. Typical values are 200-500ns for MOSFETs and 500ns-2μs for IGBTs. The dead time is inserted between turn-off of one channel and turn-on of the other, preventing shoot-through.
Calculate RDT based on required dead time. Contact our FAE team for dead time optimization.
What is the maximum switching frequency for CA-IS3221?
CA-IS3221 supports switching frequencies up to 1MHz, but practical limits depend on several factors: Propagation delay (80ns) limits maximum frequency to about 5MHz theoretically; Dead time requirement reduces effective duty cycle range at high frequencies; Gate charge and drive current determine switching time; and Power dissipation in the driver. For practical designs: Up to 500kHz is straightforward with good efficiency; 500kHz to 1MHz requires careful optimization; and Above 1MHz is generally not recommended. Most half-bridge applications operate at 100kHz to 300kHz where CA-IS3221 performs excellently.
CA-IS3221 is suitable for frequencies up to 500kHz. Contact our FAE team for high-frequency design guidance.
Can CA-IS3221 be used for synchronous rectification?
Yes, CA-IS3221 is well-suited for synchronous rectification in buck converters and full-bridge rectifiers. The programmable dead time prevents shoot-through between main switch and synchronous rectifier. For synchronous buck: Connect high-side output to control FET; Connect low-side output to sync FET; Set dead time to prevent cross-conduction; Use appropriate gate resistors. The 4A peak current drives sync FETs effectively, reducing conduction losses compared to diode rectification. The isolation allows the sync FET to be referenced to switching node while control is on primary side.
CA-IS3221 is ideal for isolated synchronous rectification. Contact our FAE team for sync rectifier design.
What is the UVLO protection in CA-IS3221?
CA-IS3221 includes Under-Voltage Lockout (UVLO) protection on both primary (VCC1) and secondary (VCC2) supplies. When VCC drops below threshold (typically 8V for VCC2), the outputs are held low to prevent operation with insufficient gate voltage. This protects power devices from operating in linear mode with high losses. UVLO has hysteresis (about 1V) to prevent oscillation during power-up. When VCC rises above threshold plus hysteresis, normal operation resumes. UVLO ensures reliable startup and prevents damage from brownout conditions.
UVLO is automatic. Ensure VCC stays above UVLO threshold during operation. Contact our FAE team for UVLO details.
How do I optimize gate resistor values for CA-IS3221?
Gate resistor optimization for CA-IS3221 involves balancing switching speed, EMI, and ringing. For half-bridge: High-side gate resistor affects turn-on of high-side FET; Low-side gate resistor affects turn-on of low-side FET; Separate source/sink resistors allow optimization. Typical approach: Start with 5-10Ω for both; Measure switching waveforms (Vgs, Vds, Id); Reduce resistance if switching is too slow or losses are high; Increase resistance if ringing or EMI is excessive; and Optimize high-side and low-side independently. Consider using different values for source (turn-on) and sink (turn-off) to optimize separately.
Start with 5-10Ω and optimize based on measurements. Contact our FAE team for gate resistor optimization.
What layout considerations are important for half-bridge drivers?
Important layout considerations for CA-IS3221 half-bridge driver: Minimize gate drive loop area (driver output → gate → source → driver GND); Place decoupling capacitors close to VCC2 and VEE2 pins; Keep high-side bootstrap capacitor close to HB and HS pins; Use kelvin connection for current sense (if used); Maintain isolation barrier clearance and creepage; Keep power traces (drain, source) away from sensitive gate drive traces; and Use adequate copper area for power dissipation. Good layout minimizes parasitic inductance that causes ringing and EMI.
Follow layout best practices for half-bridge. Contact our FAE team for layout review.