AD725ARZ - RGB to NTSC/PAL Video Encoder SOIC-16 | Analog Devices
料号： AD725ARZ ✓ 量产中| 数量 | 单价 | 小计 |
|---|---|---|
| 1 | $8.26 | $8.26 |
| 10 | $7.42 | $74.20 |
| 100 | $6.18 | $618.00 |
| 500 | $5.21 | $2,605.00 |
| 1,000 | $4.45 | $4,450.00 |
AD725ARZ 概述
What is an RGB to NTSC/PAL encoder? An NTSC/PAL encoder is a mixed-signal IC that accepts red, green and blue (RGB) video data — either as analog voltages or digital codes — and synthesizes a composite analog video waveform conforming to the NTSC (M/NTSC, 525-line, 60 Hz) or PAL (625-line, 50 Hz) broadcast standard. The encoder sits in the analog signal chain between the source (graphics controller, video DAC, framebuffer) and the display or modulator (TV, modulator, capture card). In the broader IC hierarchy, the AD725 belongs to the video encoder / video DAC family, itself a sub-category of display drivers and serializer ICs.
Key features include integrated luma (Y) and chroma (C) outputs, on-chip subcarrier generation, an integrated luma trap port for clean composite video, and a TTL-compatible digital interface for input format selection. The AD725 supports both NTSC-M and PAL-B/D/G/H/I/M/N standards with simple mode strapping, eliminating external modulator hardware. Operating from a single +5 V analog supply with low power dissipation, it requires only a handful of bypass components and a 28.63636 MHz (NTSC) or 26.84325 MHz (PAL) crystal.
Architecturally, the AD725 uses a current-output DAC topology with internal bandgap references and switched-capacitor filtering, allowing direct connection to 75 ohm video loads with minimal external components. The luma trap output and chroma output are derived from the same RGB input through an internal color-space conversion matrix and subcarrier modulator.
Typical applications include set-top box composite video outputs, video game consoles, surveillance DVRs with analog outputs, legacy industrial video overlay boards, and RGB-to-TV converter dongles. The AD725 is also common in FPGA evaluation platforms requiring analog video output and in low-cost broadcast or test equipment that needs composite NTSC/PAL modulation.
Designers should note that the part requires a high-frequency crystal oscillator reference and proper 75 ohm termination at both composite and chroma outputs. Bypass the +5 V supply with a 0.1 uF ceramic capacitor plus a 10 uF tantalum or electrolytic capacitor placed within 5 mm of the supply pin to meet PSRR specifications.
直接替换替代料： AD725ARZ ——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： AD725ARZ （相同外形与封装尺寸） ——差异在于 Luma Trap Port, Package, Packaging.
快速对比工具——选择替代料号进行并排对比：
AD725ARZ-R7
✅ 直接替换✓ 有现货
联系询价
查看数据手册 →AD725ARZ-RL
✅ 直接替换✓ 有现货
$3.27 / 个
查看数据手册 →AD725AR-REEL7
✅ 直接替换📋 参考替代料（不在目录中）
AD725ARZ 最大额定值与电气特性
| 功能 | RGB to NTSC/PAL video encoder |
| Video Standards | NTSC-M, PAL-B/D/G/H/I/M/N |
| Input Format | Analog RGB (0 V to 0.7 V) or TTL digital RGB |
| Output Format | Composite video (NTSC/PAL), Y/C (S-Video), luma trap port |
| 电源电压 | +5 V single supply |
| Reference Crystal Frequency | 28.63636 MHz (NTSC) / 26.84325 MHz (PAL) |
| Output Load | 75 ohm (composite and chroma outputs) |
| 封装 | 16-pin SOIC (SO-16, R suffix on Analog Devices R-suffix tape-and-reel grade) |
| 安装类型 | Surface Mount |
| RoHS 状态 | Compliant |
| Lead-Free | Yes |
AD725ARZ 引脚配置
| 引脚 1 | RIN — Red input (analog 0-0.7 V or TTL digital) |
| 引脚 2 | GIN — Green input (analog 0-0.7 V or TTL digital) |
| 引脚 3 | BIN — Blue input (analog 0-0.7 V or TTL digital) |
| 引脚 4 | GND — Ground |
| 引脚 5 | VDD — +5 V analog supply |
| 引脚 6 | XTAL1 — Crystal oscillator input (28.63636 MHz NTSC / 26.84325 MHz PAL) |
| 引脚 7 | XTAL2 — Crystal oscillator output |
| 引脚 8 | PAL_NTSC — Mode select: PAL high / NTSC low |
| 引脚 9 | NC — Not connected (per datasheet) |
| 引脚 10 | TRAP — Luma trap output |
| 引脚 11 | GND — Ground |
| 引脚 12 | GND — Ground |
| 引脚 13 | GND — Ground |
| 引脚 14 | GND — Ground |
| 引脚 15 | COUT — Chroma output (75 ohm) |
| 引脚 16 | CVBS — Composite video output (75 ohm) |
典型应用
AD725ARZ 适用于 7 应用s: Set-Top Box Composite Video Output, Video Game Console Analog Video Output, Surveillance DVR Analog Loop-Through, FPGA Development Board Analog Output, Industrial Overlay and Annotation Board, Low-Cost Broadcast Modulator Output Stage, Medical Imaging Analog Output.
Set-Top Box Composite Video Output
The AD725ARZ is widely deployed as the composite video encoder in set-top boxes that need to deliver an analog NTSC or PAL signal to legacy televisions. Its on-chip subcarrier generator, integrated 75-ohm driver, and selectable NTSC/PAL operation remove the need for an external modulator, keeping the BOM small. When driven from a digital RGB bus, the encoder accepts standard TTL levels; when driven from analog RGB, inputs of 0 V to 0.7 V are supported directly. The 16-pin SOIC package is small enough for compact set-top enclosures, and the single +5 V supply aligns with the +5 V rails already present in these designs.
推荐
Video Game Console Analog Video Output
Retro consoles and FPGA-based game emulators use the AD725ARZ to convert digital RGB from the graphics pipeline into a composite or Y/C output that connects to consumer CRTs. Its tolerance of TTL RGB levels and integrated DACs simplify the interface between FPGA transceivers and the analog output stage. Compared with discrete encoder implementations, the AD725ARZ saves board area, eliminates crystal-oscillator matching problems, and produces a clean chroma signal with low differential gain and phase. Designers should place a 0.1 uF ceramic bypass capacitor plus a 10 uF bulk capacitor on the +5 V pin within 5 mm of the IC.
推荐
Surveillance DVR Analog Loop-Through
DVRs and security capture cards use the AD725ARZ to drive analog video loop-through outputs from decoded digital streams, allowing installers to feed the signal into an existing analog CCTV infrastructure. The encoder's low power and high PSRR on the +5 V rail keep noise coupling into the composite output to a minimum, which is critical for long cable runs where the chroma band can otherwise degrade. Compared with higher-cost multi-format encoders, the AD725ARZ targets composite-only designs and provides the best cost-to-performance trade-off for surveillance installations.
推荐
FPGA Development Board Analog Output
FPGA development kits and educational boards use the AD725ARZ to expose analog composite video on an RCA jack for direct connection to a TV or capture card. The encoder accepts digital RGB straight from FPGA pins, eliminating the need for an external video DAC. With the crystal reference chosen correctly (28.63636 MHz for NTSC, 26.84325 MHz for PAL), the board can output standard NTSC or PAL signals with no additional hardware beyond a few bypass capacitors and a 75-ohm output matching network.
推荐
Industrial Overlay and Annotation Board
Industrial test, broadcast and instrumentation equipment uses the AD725ARZ to overlay text or graphics onto an analog NTSC/PAL video signal. The encoder's RGB inputs can be driven by a low-cost microcontroller with PWM outputs or by a small FPGA block, while the composite output feeds downstream recorders or displays. Its industrial operating temperature grade and RoHS compliance make it suitable for long-life industrial installations, and the SOIC-16 footprint keeps it usable on compact PCBs where space is constrained.
推荐
Low-Cost Broadcast Modulator Output Stage
Low-cost RF modulators and channel-injector modules integrate the AD725ARZ as the analog front-end that feeds the modulator stage, producing a baseband output which is then upconverted to channel 3/4 RF. The encoder's low spurious subcarrier content and clean chroma spectrum minimize out-of-band emissions, simplifying the post-encoder RF filter design. Compared with multi-format encoders, the AD725ARZ targets single-standard designs and reduces both part cost and design complexity.
推荐
Medical Imaging Analog Output
Medical imaging systems with analog video outputs (such as legacy ultrasound or endoscopy carts) use the AD725ARZ to convert RGB framebuffer output into a composite NTSC/PAL signal that connects to analog recording equipment or external monitors. The encoder's RoHS compliance and reliability make it suitable for medical designs that require long-term stability. Designers should provide robust +5 V supply decoupling to keep differential gain and phase within medical-grade tolerance.
推荐
推荐产品汇总
工程参考数据： AD725ARZ ——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 | AD725ARZ-R7 | AD725ARZ-RL | AD725AR-REEL7 |
|---|---|---|---|---|
| Package | SOIC-16 (SO-16, 150-mil) | SOIC-16 - same | SOIC-16 - same | SOIC-16 - same |
| Brand | Analog Devices | Analog Devices - same | Analog Devices - same | Analog Devices - same |
| Function | RGB to NTSC/PAL encoder | RGB to NTSC/PAL encoder | RGB to NTSC/PAL encoder | RGB to NTSC/PAL encoder |
| Video Standards | NTSC-M, PAL-B/D/G/H/I/M/N | NTSC-M, PAL-B/D/G/H/I/M/N | NTSC-M, PAL-B/D/G/H/I/M/N | NTSC-M, PAL-B/D/G/H/I/M/N |
| Supply Voltage | +5 V single supply | +5 V single supply | +5 V single supply | +5 V single supply |
| Crystal Reference | 28.63636 MHz (NTSC) / 26.84325 MHz (PAL) | Same reference frequencies | Same reference frequencies | Same reference frequencies |
| Packaging Form | Tape & Reel (ARZ grade) | Tape & Reel 7-inch reel | Tape & Reel 13-inch reel | Tape & Reel 7-inch reel |
| Lead-Free / RoHS | Yes / Compliant | Yes / Compliant | Yes / Compliant | Yes / Compliant |
| Pin Count | 16 pins | 16 pins | 16 pins | 16 pins |
关键差异点
- Industry-standard monolithic RGB-to-NTSC/PAL encoder with integrated subcarrier generator （对比 AD725ARZ-R7)
- Single +5 V supply eliminates need for negative rails （对比 Discrete RGB-to-video implementations)
- On-chip 75-ohm drivers for composite and chroma outputs （对比 ADV7341 multi-format encoder)
设计说明
Bypass the +5 V supply (pin 5) with a 0.1 uF ceramic capacitor plus a 10 uF tantalum or ceramic capacitor. The 0.1 uF must be placed within 5 mm of the supply pin and the ground return should be a short, low-inductance trace to a nearby ground pin (4, 11, 12, 13 or 14). For multi-board systems, place additional bulk capacitance at the regulator output. Estimated: insufficient decoupling degrades differential gain and increases chroma noise, directly affecting the composite output's color accuracy on long cable runs.
The CVBS (pin 16) and COUT (pin 15) outputs drive 75 ohm transmission lines directly. Use a controlled-impedance trace of 75 ohms characteristic impedance or place series ferrite beads when longer than 50 mm. Place the 75-ohm output termination resistors as close to the output pins as possible to reduce ringing and overshoot on the chroma waveform. Keep analog and digital return currents separated by using a star-ground topology at the IC ground pins (4, 11-14).
Crystal selection is critical: use a parallel-resonant fundamental-mode crystal with load capacitance matching the AD725 datasheet recommendation. Series combination of the two external capacitors (one at XTAL1, one at XTAL2) should approximately equal the crystal manufacturer's specified parallel capacitance. Common pitfalls include using series-resonant-mode crystals (causes frequency error), using overtone crystals (causes oscillation at wrong mode), and omitting the load capacitors (causes subcarrier frequency error).
When driven from digital logic (TTL RGB), keep input traces short to avoid reflections. The RGB inputs are high-bandwidth and a 33 ohm series damping resistor may be needed for traces longer than 25 mm. Estimated: at 28.63636 MHz reference, edge rates of <5 ns on TTL inputs can couple noise into the analog output if traces are not properly terminated. For analog RGB inputs, keep traces away from switching power and digital clocks.
合规信息
RoHS and REACH compliant per Abacus Technologies product listing; lead-free with matte-tin terminations. AEC-Q100 not applicable for video encoder ICs. Conflict Minerals status: DRC Conflict Free per Abacus listing.
