CMPP6028R - 40V, 150mA Programmable UJT, SOT-23 | Central Semiconductor
料号： CMPP6028R ✗ 停产| 数量 | 单价 | 小计 |
|---|---|---|
| 1 | $0 | $0.00 |
| 10 | $0 | $0.00 |
| 100 | $0 | $0.00 |
| 500 | $0 | $0.00 |
| 1,000 | $0 | $0.00 |
CMPP6028R 概述
A programmable unijunction transistor is a four-layer PNPN device belonging to the thyristor family. It behaves as a voltage-triggered switch: when the anode voltage exceeds a threshold set by the gate divider network, the device fires and conducts from anode to cathode. PUTs are widely used as relaxation oscillators, timing circuits, voltage detectors, and SCR trigger devices, occupying the low-power end of the power-management and discrete-semiconductor hierarchy.
Key features of the CMPP6028R include a 40 V anode-to-cathode voltage rating, a 150 mA maximum current capability, and a compact SOT-23 surface-mount package suitable for automated assembly. The programmability of IP, IV, and eta gives it flexibility that fixed-parameter UJTs cannot offer, allowing one part number to serve many oscillator and timing designs.
Architecturally, the CMPP6028R implements the anode-gate-cathode structure of a PUT with the gate accessible on a package pin. The intrinsic standoff ratio and peak/valley currents are set externally: increasing the gate divider resistance raises the standoff ratio and reduces peak current, tuning oscillator frequency and triggering thresholds. Maximum power dissipation for this family is 167 mW per the manufacturer data.
Typical applications include relaxation oscillators, long-duration timers, overvoltage detectors, lamp flashers, and gate-trigger circuits for SCRs and triacs in low-power industrial and consumer designs.
Design consideration: keep total dissipation within the 167 mW package limit and ensure the external divider current substantially exceeds the valley current so oscillation does not stall.
This page synthesizes distributor availability data, drop-in alternatives, and practical design notes not found in the manufacturer datasheet.
直接替换替代料： CMPP6028R ——相同封装，引脚兼容。需要 PCB 改动的不同封装料号已排除。
本系列中的变体
可与以下型号直接替换的同系列型号： CMPP6028R （相同外形与封装尺寸） ——差异在于 Device Type, Package.
快速对比工具——选择替代料号进行并排对比：
CMPP6027R
✅ 直接替换✓ 有现货
$0.17 / 个
查看数据手册 →CMPP6027
✅ 直接替换 ⚠️ 规格未核验📋 参考替代料（不在目录中）
CMPP6028R 规格参数
| Device Type | Silicon Programmable Unijunction Transistor (PUT) |
| Maximum Voltage | 40 V |
| Maximum Current | 150 mA |
| Maximum Power Dissipation | 167 mW |
| Programmable Parameters | Valley current (IV), peak current (IP), intrinsic standoff ratio (eta) |
| 封装 | SOT-23 (surface mount) |
| 安装类型 | Surface Mount |
| Polarity | PNPN (anode-gate-cathode) |
| Packaging Option (BK suffix) | Bulk |
| Packaging Option (TR suffix) | Tape & Reel |
CMPP6028R sot-23 (surface mount) 引脚配置指南
CMPP6028R（sot-23 (surface mount) 封装）的引脚配置。 引脚编号、功能和连接图在制造商数据手册中定义。请参阅该手册以了解确切的封装尺寸和焊接指南。
暂无详细引脚数据： CMPP6028R.
请参阅 数据手册 以查看完整引脚配置。
典型应用
CMPP6028R 适用于 6 应用s: Relaxation Oscillators, Precision Timers and Time-Delay Circuits, Overvoltage Detection and Crowbar Triggering, SCR and TRIAC Gate Triggering, Lamp Flashers and Indicator Circuits, Sawtooth and Ramp Generators.
Relaxation Oscillators
The CMPP6028R is purpose-built for relaxation oscillators: its externally programmable peak current (IP), valley current (IV), and intrinsic standoff ratio (eta) let a designer set frequency and hysteresis with just a timing capacitor and two gate-divider resistors. The device charges the capacitor through a resistor; when the anode crosses the programmed gate threshold, the PUT fires and discharges the capacitor, repeating cyclically. Because IP can be programmed low, very long time constants and low supply currents are achievable, which fixed-UJT designs cannot match. Ensure the charging current through the timing resistor stays above valley current (IV) at minimum supply, or oscillation will latch off; per the datasheet this programmability is the core design intent of the CMPP6027R/CMPP6028R family.
推荐
Precision Timers and Time-Delay Circuits
In long-duration timer circuits the CMPP6028R excels because its low programmable peak current allows large timing resistors and capacitors, stretching delay periods into seconds or minutes without electrolytic-quality capacitors. The PUT fires when the integrating node reaches the gate-set threshold, driving a load or an SCR. The standoff ratio (eta), programmed by the gate divider, defines the trigger point as a fraction of supply voltage, so timing accuracy follows divider precision - use 1% resistors for predictable thresholds. Compared with a 555 timer, the CMPP6028R draws far less standing current and tolerates higher supply voltages up to its 40 V rating, making it attractive for battery-backed and industrial delay-on/delay-off functions.
推荐
Overvoltage Detection and Crowbar Triggering
The CMPP6028R functions as a sensitive voltage-level detector: a resistor divider feeds the anode while the gate divider sets the trip threshold. When a monitored rail exceeds the programmed point, the PUT fires and can directly trigger an SCR crowbar, shutting down the faulted supply. Its 40 V rating covers most intermediate DC buses, and the SOT-23 package fits densely on protection PCBs. Programmable IP lets the designer set immunity against noise-induced false triggers while remaining sensitive enough to catch genuine overvoltage events quickly. Place the device upstream of the SCR gate with a small series resistor to limit gate current, and verify that sustained PUT conduction within the crowbar window stays within the 167 mW package dissipation limit.
推荐
SCR and TRIAC Gate Triggering
As a pulse generator for thyristor gates, the CMPP6028R provides a sharp, low-impedance discharge pulse from a timing capacitor when it fires, delivering the di/dt that SCRs and TRIACs need for reliable latch-up. The programmable standoff ratio allows the trigger phase angle to be set against a synchronized ramp, supporting simple phase-control circuits for heaters, lamps, and small motors. Its 150 mA pulse capability is adequate for sensitive-gate SCRs; larger devices may need a pulse transformer or transistor buffer after the PUT. Because it is obsolete, new designs should verify long-term supply or adopt the CMPP6027R sibling. Keep gate-drive pulse width and energy within the target thyristor datasheet requirements for the full operating temperature range.
推荐
Lamp Flashers and Indicator Circuits
The CMPP6028R makes efficient low-parts-count lamp or LED flashers: a capacitor charges toward the supply through a resistor, and when the PUT fires the stored charge dumps through the lamp or LED, producing a bright flash from a low average current. Because IP and IV are programmable, flash rate and duty cycle can be tuned over a wide range while operating from supplies up to 40 V, well above typical IC timer limits. Average battery drain is dominated by the gate divider and charging resistor, so select divider values that balance threshold stability against quiescent draw. The SOT-23 surface-mount package supports compact indicator PCBs in industrial panels, battery-powered devices, and warning-beacon applications.
推荐
Sawtooth and Ramp Generators
In analog function generation, the CMPP6028R resets a ramp capacitor each cycle: a constant-current source or high-value resistor charges the capacitor linearly, and the PUT discharges it rapidly at the programmed threshold, producing a sawtooth waveform for sweep, PWM-ramp, or ADC-driving applications. The programmable standoff ratio sets ramp amplitude precisely as a fraction of the supply, and low IP permits very slow, low-current ramps. Rise-time linearity depends on the charging network rather than the PUT itself, so a current source improves fidelity over a simple resistor. Recovery time after discharge is short in the SOT-23 device, supporting repetition rates from sub-hertz to tens of kilohertz depending on capacitor size and discharge-path impedance.
推荐
工程参考数据： CMPP6028R ——对比、设计指导和合规信息。
选型指南
与替代料对比
| 参数 | 本产品 | CMPP6027R | CMPP6027 |
|---|---|---|---|
| Package | SOT-23 | SOT-23 - same | SOT-23 - same |
| Brand | Central Semiconductor | Central Semiconductor | Central Semiconductor |
| Device Type | Programmable UJT (PUT) | Programmable UJT (PUT) | Programmable UJT (PUT) |
| Programmable Parameters | IP, IV, eta (external resistors) | IP, IV, eta (external resistors) | IP, IV, eta (external resistors) |
关键差异点
- Externally programmable IP, IV, and standoff ratio （对比 CMPP6027R)
- Surface-mount SOT-23 in a PUT function （对比 CMPP6027)
- 40 V, 150 mA ratings suit higher-voltage timing rails （对比 CMPP6027R)
设计说明
The most frequent CMPP6028R failure mode in oscillator designs is a charging current below valley current (IV), which causes the circuit to start once and then latch off. Per the series datasheet, IV is programmable via the gate divider - calculate it for your minimum supply and maximum temperature, then size the timing resistor so I_charge > IV with margin. Also confirm the peak anode voltage stays below the 40 V rating under all line and load conditions.
Keep total dissipation within the 167 mW family maximum. Estimated: in a flasher or oscillator, average power equals supply voltage times average current (gate divider standing current plus charge/discharge duty). For example, at 24 V and 5 mA average drain, dissipation is 120 mW - within limits, but derate for elevated ambient per the datasheet derating curve. Continuous-conduction applications (detectors holding on) need the most careful check.
Place the gate divider resistors close to the SOT-23 gate pin and keep the timing-node track short to minimize stray capacitance, which shifts the effective threshold and oscillator frequency at high values of timing resistance. Use 1% resistors in the gate divider for repeatable standoff ratio (eta). The obsolete status of this part also argues for laying out the SOT-23 footprint so the CMPP6027R family member can be dropped in without PCB rework.
合规信息
Compliance status not stated in the retrieved web data. A Pb-free variant (CMPP6027 TR PBFREE) appears in Octopart comparisons, suggesting family members exist in lead-free options; verify with Central Semiconductor for the CMPP6028R specifically.
