Specifications
| Type | Description |
|---|---|
| Part Number | NCP1234 |
| Manufacturer | STMicroelectronics |
| Product Type | LDO Regulator |
| Category | Power Management |
| Package / Case | SOIC-7, CASE 751U |
| Component Type | Power_IC |
| Controller topology | Fixed-frequency current-mode controller for flyback converters |
| Oscillator frequency options | 65 kHz or 100 kHz |
| VCC voltage range absolute maximum | -0.3 to 28 V |
| VCC current range absolute maximum | ±30 mA |
| HV voltage range absolute maximum | -0.3 to 500 V |
| HV current range absolute maximum | ±20 mA |
| Driver voltage range absolute maximum | -0.3 to 20 V |
| Driver current range absolute maximum | ±1000 mA |
| Other pins voltage range absolute maximum | -0.3 to 10 V |
| Other pins current range absolute maximum | ±10 mA |
| Thermal resistance junction-to-air | 162 °C/W |
| Thermal resistance junction-to-air | 147 °C/W |
| Thermal resistance junction-to-air | 115 °C/W |
| Operating junction temperature range | -40 to +150 °C |
| Storage temperature range | -60 to +150 °C |
| ESD human body model | 2000 V |
| ESD machine model | 200 V |
| Minimum voltage for current source operation | typ 30 V, max 40 V |
| Startup current | min 0.2 mA, typ 0.5 mA, max 0.8 mA |
| Startup current | min 3 mA, typ 6 mA, max 9 mA |
| HV off-state leakage current | typ 25 µA, max 50 µA |
| VCC turn-on threshold | min 11.0 V, typ 12.0 V, max 13.0 V |
| HV current source restart threshold | min 9.5 V, typ 10.5 V, max 11.5 V |
| VCC turn-off threshold | min 8.5 V, typ 9.5 V, max 10.5 V |
| VCC overvoltage threshold | min 25 V, typ 26.5 V, max 28 V |
| VCC fault blanking duration | min 7 µs, typ 10 µs, max 13 µs |
| Internal logic reset threshold | min 3.6 V, typ 5.0 V, max 6.0 V |
| ISTART1 to ISTART2 transition threshold | min 0.4 V, typ 1.0 V, max 1.6 V |
| Internal current consumption | min 1.2 mA, typ 1.8 mA, max 2.2 mA |
| Internal current consumption | min 1.3 mA, typ 1.9 mA, max 2.3 mA |
| Internal current consumption | min 1.9 mA, typ 2.5 mA, max 3.2 mA |
| Internal current consumption | min 2.2 mA, typ 2.9 mA, max 3.6 mA |
| Off mode current consumption | min 0.67 mA, typ 0.9 mA, max 1.13 mA |
| Fault mode current consumption | min 0.4 mA, typ 0.7 mA, max 1.0 mA |
| Oscillator frequency | min 60 kHz, typ 65 kHz, max 70 kHz |
| Oscillator frequency | min 92 kHz, typ 100 kHz, max 108 kHz |
| Maximum duty cycle | min 75 %, typ 80 %, max 85 % |
| Frequency jittering amplitude | min ±4 %, typ ±6 %, max ±8 % |
| Frequency jittering modulation frequency | min 85 Hz, typ 125 Hz, max 165 Hz |
| Driver rise time | typ 40 ns, max 70 ns |
| Driver fall time | typ 40 ns, max 70 ns |
| Driver source current capability | typ 500 mA |
| Driver sink current capability | typ 500 mA |
| Driver clamping voltage | min 11 V, typ 13.5 V, max 16 V |
| Driver high-state voltage drop | max 1 V |
| FB internal pull-up resistor | min 15 kΩ, typ 20 kΩ, max 25 kΩ |
| VFB to internal current setpoint division ratio | min 4.7, typ 5, max 5.3 |
| FB internal pull-up voltage | min 4.3 V, typ 5 V, max 5.7 V |
| Current sense input bias current | typ 0.02 µA |
| Maximum internal current setpoint | min 0.66 V, typ 0.7 V, max 0.74 V |
| Current-limit propagation delay | typ 80 ns, max 110 ns |
| Leading edge blanking duration | min 190 ns, typ 250 ns, max 310 ns |
| Immediate fault protection threshold | min 0.95 V, typ 1.05 V, max 1.15 V |
| Leading edge blanking duration for immediate fault | min 90 ns, typ 120 ns, max 150 ns |
| Compensation ramp slope | typ -32.5 mV/µs |
| Compensation ramp slope | typ -50 mV/µs |
| Soft-start duration | min 2.8 ms, typ 4.0 ms, max 5.2 ms |
| Overpower compensation conversion ratio | typ 0.54 µA/V |
| Overpower compensation current | typ 0 µA |
| Overpower compensation current | typ 20 µA |
| Overpower compensation current | typ 110 µA |
| Overpower compensation current | min 105 µA, typ 130 µA, max 150 µA |
| FB voltage above which IOPC is applied | min 2.12 V, typ 2.35 V, max 2.58 V |
| FB voltage below which no IOPC is applied | typ 2.15 V |
| DC operation watchdog timer | typ 32 ms |
| HV sampling level | typ 92 V |
| Fault timer duration | min 98 ms, typ 128 ms, max 168 ms |
| Autorecovery latch-off duration | min 0.85 s, typ 1.00 s, max 1.35 s |
| Frequency foldback start threshold | min 1.8 V, typ 2.0 V, max 2.2 V |
| Frequency foldback complete threshold | min 1.22 V, typ 1.35 V, max 1.48 V |
| Minimum switching frequency | min 22 kHz, typ 27 kHz, max 32 kHz |
| Skip mode entry threshold | min 0.63 V, typ 0.7 V, max 0.77 V |
| Skip mode exit threshold | min 0.72 V, typ 0.80 V, max 0.88 V |
| Latch-off high threshold | min 2.35 V, typ 2.5 V, max 2.65 V |
| Latch-off low threshold | min 0.76 V, typ 0.8 V, max 0.84 V |
| Latch NTC current source | min 65 µA, typ 95 µA, max 105 µA |
| Latch NTC current source during soft-start | min 130 µA, typ 190 µA, max 210 µA |
| High latch detection blanking duration | min 35 µs, typ 50 µs, max 70 µs |
| High latch detection blanking duration | min 25 µs, typ 35 µs, max 45 µs |
| Low latch detection blanking duration | typ 350 µs |
| Latch clamp voltage | min 1.0 V, typ 1.2 V, max 1.4 V |
| Latch clamp voltage | min 2.0 V, typ 2.4 V, max 3.0 V |
| Temperature shutdown | min 135 °C, typ 150 °C, max 165 °C |
| Temperature shutdown hysteresis | min 20 °C, typ 30 °C, max 40 °C |
| Datasheet Status | request_only |
Product Overview
The device is supplied in an SOIC-7, CASE 751U package. Maximum ratings include -0.3 to 28 V on VCC, -0.3 to 500 V on the HV pin, -0.3 to 20 V on DRV, and -0.3 to 10 V on other pins. Thermal resistance junction-to-air is specified at 162 °C/W, 147 °C/W, or 115 °C/W depending on PCB conductivity, and the operating junction temperature range is -40 to +150 °C.
Control and protection specifications cover startup current, VCC turn-on and turn-off thresholds, VCC overvoltage, current-limit delay, leading-edge blanking, immediate fault protection, overpower compensation, autorecovery timing, latch thresholds, and temperature shutdown. These parameters make the part applicable to flyback converter designs that require current-mode regulation, driver control, startup from a high-voltage pin, and defined fault behavior.
Key Features
- Fixed-frequency current-mode controller for flyback converters
- 65 kHz and 100 kHz oscillator versions
- High-voltage pin absolute maximum rating to 500 V
- VCC turn-on threshold specified from 11.0 to 13.0 V
- Typical 500 mA driver source and sink capability
- Maximum duty cycle specified from 75% to 85%
- Frequency jittering amplitude specified at ±4% to ±8%
- Soft-start duration specified from 2.8 ms to 5.2 ms
- Current-limit propagation delay typically 80 ns
- Skip mode entry and exit thresholds are defined
- Autorecovery latch-off duration specified around 1 second
- Thermal shutdown threshold specified from 135°C to 165°C
Typical Applications
- Flyback converters
- Current-mode power supplies
- Fixed-frequency converter control
- 65 kHz flyback designs
- 100 kHz flyback designs
- Skip-mode power operation
- Frequency foldback converter designs
- High-voltage startup circuits
- Fault-protected flyback controllers
Procurement Notes
When requesting a quote for NCP1234, buyers should confirm the manufacturer, package or case, required quantity, target date code, compliance documents, packing method, destination country and expected delivery schedule.
If alternatives are acceptable, buyers should share the approved vendor list, required electrical or optical limits, package constraints and qualification requirements. Any alternative part should be reviewed by the buyer's engineering team before production use.
For power IC and power device sourcing, voltage rating, current rating, power dissipation, package thermal performance, protection features, qualification grade and application conditions should be reviewed before approval.
FAQ
What type of controller is the NCP1234?
NCP1234 is specified as a fixed-frequency current-mode controller for flyback converters. The extracted device description identifies it as a flyback current-mode controller in the Power_Management category.
Which oscillator frequencies are available for NCP1234?
The datasheet facts list two device frequency options: 65 kHz and 100 kHz. The 65 kHz version is specified from 60 to 70 kHz, while the 100 kHz version is specified from 92 to 108 kHz.
What package is listed for the NCP1234?
The package case provided for NCP1234 is SOIC-7, CASE 751U. Thermal resistance junction-to-air is specified for this package at 162, 147, or 115 °C/W depending on PCB conductivity.
What driver capability is specified for NCP1234?
The DRV pin has an absolute maximum current range of ±1000 mA. Driver source and sink current capability are both listed as typical 500 mA, with rise and fall times typically 40 ns and maximum 70 ns under the stated test conditions.
What protection thresholds are documented for the controller?
The extracted facts include VCC turn-off, VCC overvoltage, immediate current-sense fault, latch-off high and low thresholds, fault timer duration, autorecovery latch-off duration, and temperature shutdown with hysteresis.
Technical Review & Sourcing Note
Prepared by LDeepAI Component Sourcing Team. Reviewed for RFQ, documentation and alternative sourcing use. Last updated: July 26, 2026.
This page is based on manufacturer datasheet information and LDeepAI sourcing review. Specifications should be verified against the official manufacturer datasheet before final procurement or design approval. Final electrical, optical and reliability approval should be confirmed by the buyer's engineering team.