Intel

EP20K100EFC324-2X - APEX 20KE 100K Gates FPGA | Intel / Altera

부품 번호: EP20K100EFC324-2X ✗ 단종
재고 있음 영업일 기준 1~3일 내 발송
1.8 V Vdss 324-ball FBGA (FineLine BGA), 19x19 mm, 1.27 mm pitch Package Up to 250 MHz Speed
시작가 $99.5 USD / 개
MOQ: 1 |
가격 업데이트: 2026-09-07
볼륨 가격
수량 단가 합계
1 $185 $185.00
10 $162 $1,620.00
100 $138 $13,800.00
500 $118 $59,000.00
1,000 $99.5 $99,500.00
ℹ️ 모든 가격은 USD 기준입니다

EP20K100EFC324-2X 개요

The Intel / Altera EP20K100EFC324-2X is a member of the APEX 20KE family of Field Programmable Gate Arrays (FPGAs), delivering 100,000 system gates, 4,160 logic elements (cells), and 53,248 bits of embedded RAM in a 324-ball FineLine BGA (FBGA) package. The device is fabricated on a 0.22 µm (per FindIC) all-layer copper-metal CMOS process and operates with a core supply of 1.8 V, with the speed grade "-2X" offering up to 250 MHz internal operation. The package pin pitch is 1.27 mm and the device exposes up to 246 user I/O pins (per DigiKey, Mouser and Intel / Altera datasheets).

An FPGA (Field Programmable Gate Array) is a type of Programmable Logic Device (PLD) that combines a large array of configurable logic blocks (LABs/CLBs), embedded memory blocks, I/O elements, and programmable interconnect into a single semiconductor IC. FPGAs occupy the high-density end of the programmable-logic hierarchy (above CPLDs and SPLDs) and are widely used for parallel DSP, custom glue logic, bus interfacing, and prototype ASIC replacement. The APEX 20KE family, in particular, pioneered multi-core architecture (MegaLAB) that combines lookup tables, product-term logic and Embedded Array Blocks (EABs) on a single die.

Key features of the EP20K100EFC324-2X include: 100K system gates, 4,160 logic cells, 53248 bits of embedded RAM, 416 LABs/CLBs, 246 maximum user I/Os, 1.8 V core supply, in-system programmability via IEEE 1149.1 JTAG, MultiVolt I/O support for interfacing to 1.8 V / 2.5 V / 3.3 V logic, and a 4-input Look-Up Table (LUT)-based fine-grain architecture. The -2X speed grade delivers approximately 35% faster design performance than the original APEX 20K family, according to Altera's published device-family literature.

The device uses a fine-grain, LUT-based architecture organized into MegaLAB structures that contain 16 Logic Array Blocks (LABs), an Embedded System Block (ESB) of 2 Kbits, and dedicated carry chains for fast arithmetic. Distributed and block RAM combined with dedicated clock networks and PLL-style clock-management blocks (per Altera APEX 20KE family documentation) simplify high-speed digital design. Configuration is stored in SRAM cells and is loaded via JTAG, passive serial, passive parallel, or Altera configuration EPROMs.

Typical applications include telecommunications line-card glue logic, industrial control and factory-automation controllers, ASIC prototyping, DSP coprocessing front-ends, custom bus-bridges, and PCI interface bridging. Its 246 user I/Os make it well-suited to legacy parallel-bus and memory-interface designs that predate modern System-on-Chip integration.

A key design consideration with the EP20K100EFC324-2X is that the APEX 20KE family has been NRND (Not Recommended for New Designs) by Intel / Altera for many years, so engineers should plan a migration path to a Cyclone, MAX, or Stratix equivalent for new production. The FBGA-324 (19x19 mm) package requires careful PCB layout with microvia or via-in-pad technology to route signals out of the inner balls.

This page synthesizes distributor pricing, drop-in same-family alternatives, FBGA-324 footprint compatibility notes, and practical APEX 20KE design migration guidance not aggregated on any single distributor listing.

드롭인 대체품: EP20K100EFC324-2X — 동일 패키지, 핀 호환. PCB 재작업이 필요한 다른 패키지 부품은 제외됩니다.

이 시리즈의 변형

다음과 드롭인 호환되는 동일 시리즈 모델: EP20K100EFC324-2X (동일 폼 팩터 및 풋프린트) — 차이점: Family, Process Technology, Package, Operating Temperature, Series.

Altera
Family: APEX-20KE
Process Technology: 0.15 µm all-layer copper CMOS
Package: 324-BGA (FineLine BGA)
비교 대상: EP20K100EFC324-2X →
Intel
Operating Temperature: 0C to +85C (commercial)
Series: APEX-20K®
비교 대상: EP20K100EFC324-2X →
Altera
Family: APEX 20K
Process Technology: 0.22 micrometer CMOS
Package: 324-FBGA (19x19 mm, 1.0 mm pitch)
비교 대상: EP20K100EFC324-2X →
Altera
Family: APEX-20K
Process Technology: 0.22 µm CMOS
Package: 324-ball FineLine BGA (FBGA)
비교 대상: EP20K100EFC324-2X →
Intel
Family: APEX 20K (non-KE)
Process Technology: 0.22 µm CMOS
Package: 324-pin FBGA (Fine-pitch BGA)
비교 대상: EP20K100EFC324-2X →
Altera
Family: APEX-20KE (1.8V, LVDS)
Process Technology: 0.22 micrometer
Series: APEX-20KE
비교 대상: EP20K100EFC324-2X →
Altera
Family: APEX 20KE (MultiCore architecture)
Process Technology: 1.8 V, 0.18 micrometer CMOS
Package: 324-FBGA (19 mm x 19 mm)
비교 대상: EP20K100EFC324-2X →

빠른 비교 도구 — 나란히 비교할 대체 부품을 선택하십시오:

EP20K100EFC324-2

✅ 드롭인
📦 324-ball FBGA (19x19 mm)
same die, -2 base speed grade (~35% slower timing margin than -2X), pin-compatible

📋 참조 대체품 (카탈로그에 없음)

EP20K200EFC324-2X

✅ 드롭인
📦 324-ball FBGA (19x19 mm)
same FBGA-324 footprint, 200K gates (2x logic capacity), pin-compatible upgrade path

📋 참조 대체품 (카탈로그에 없음)

EP20K100EFC324-1N

✅ 드롭인
Altera
📦 324-ball FBGA (19x19 mm)
APEX-20KE · FPGA (Field Programmable Gate Array) · 4160 · 100,000 · 246 · 53248 bits · 324-BGA (FineLine BGA) · 0 C to 85 C

✓ 재고 있음

$108 / 개

데이터시트 보기 →
ℹ️ 2 교차 패키지 부품은 숨겨졌습니다 — 다른 패키지는 PCB 재작업이 필요하며 진정한 드롭인 대체품이 아닙니다. 문의하기 교차 패키지 제안이 필요하면 다음을 참조하십시오.

EP20K100EFC324-2X 최대 정격 & 전기적 특성

Family APEX 20KE
Device Type SPLD / FPGA (Field Programmable Gate Array)
System Gates 100,000 gates
Logic Elements / Cells 4,160
Total RAM Bits 53,248 bits
LABs / CLBs 416
Maximum User I/Os 246
Number of I/O Banks 8 (per APEX 20KE family)
Propagation Delay 1.6 ns
Internal Operating Frequency Up to 250 MHz
Core Supply Voltage (VCCINT) 1.8 V
I/O Supply Voltage (VCCIO) MultiVolt: 1.8 V / 2.5 V / 3.3 V
Process Technology 0.22 µm CMOS (all-layer copper metal)
Speed Grade -2X
패키지 324-ball FBGA (FineLine BGA), 19x19 mm, 1.27 mm pitch
실장 유형 Surface Mount
동작 온도 0 °C to 85 °C (Commercial)
Programming Interface IEEE 1149.1 JTAG
Configuration Modes Passive Serial, Passive Parallel, JTAG, Altera configuration EPROM

EP20K100EFC324-2X 324-ball fbga (fineline bga), 19x19 mm, 1.27 mm pitch 핀 구성 가이드

EP20K100EFC324-2X(324-ball fbga (fineline bga), 19x19 mm, 1.27 mm pitch 패키지)의 핀 구성입니다. 이 디지털 IC에는 GPIO, 통신 인터페이스(UART, SPI, I2C), 전원 핀이 포함되어 있습니다. 대체 핀 기능과 구성 옵션은 제조사 데이터시트를 참조하십시오. 임베디드 시스템 설계와 PCB 레이아웃에 필수적입니다.

EP20K100EFC324-2X의 324-ball fbga (fineline bga), 19x19 mm, 1.27 mm pitch 패키지 핀아웃 다이어그램

다음에 대한 상세 핀아웃 데이터 없음: EP20K100EFC324-2X.

다음을 참조하십시오: 데이터시트 전체 핀 구성은 다음을 참조하십시오.

일반적인 애플리케이션

EP20K100EFC324-2X 적합 용도: 6 애플리케이션s: Telecommunications Line-Card Glue Logic, Industrial Control and Factory Automation Controllers, ASIC Prototyping and Validation, Custom Bus Bridges and Protocol Converters, DSP Coprocessor Front-End, Legacy PCI Interface Card Designs.

🌐

Telecommunications Line-Card Glue Logic

The EP20K100EFC324-2X fits telecom line-card glue logic because its 100K system gates, 4,160 logic cells and 246 user I/Os are enough to bridge legacy TDM buses, framing devices and network processors without a co-processor. The MultiVolt I/O (1.8/2.5/3.3 V on VCCIO banks) lets the device talk directly to 3.3 V PHY chips while running its core at 1.8 V, which simplifies mixed-voltage board design. The 53,248 bits of embedded RAM serve as fast lookup-table and packet-header storage for backplane routing. Compared with an ASIC redesign cycle of 12-18 months, this FPGA can be programmed in days via JTAG, accelerating NPI for last-mile DSLAM and SONET line cards.

🏭

Industrial Control and Factory Automation Controllers

For industrial PLC and motion-control cards, the EP20K100EFC324-2X delivers deterministic logic through its 4-input LUT-based fabric and dedicated carry chains, which give predictable timing for encoder quadrature decoding and PWM generation. The 246 I/Os support a large number of 24 V opto-isolated digital inputs and relay-driver outputs in parallel, eliminating the need for external mux expanders. Operating from a 1.8 V core, the device dissipates roughly 0.5-1 W in typical gate-utilization designs, which simplifies thermal design inside sealed IP65 enclosures. Existing field installations can keep running on this part while new designs move to MAX 10 or Cyclone IV E for active lifecycle support.

🖥️

ASIC Prototyping and Validation

The EP20K100EFC324-2X is widely used as an ASIC prototype vehicle because its 100K gates and 246 I/Os are large enough to map an entire mid-complexity ASIC RTL netlist. Engineers partition the design across multiple APEX 20KE devices and use JTAG-based multi-device configuration chains to validate the ASIC's real-world I/O behaviour, timing margins and bus protocols before committing to mask tooling. The 53,248-bit embedded RAM also helps emulate SRAM blocks and FIFO buffers that the final ASIC will integrate. Quartus II synthesis flow matches typical ASIC synthesis, so timing closure on the FPGA is a good predictor of post-layout ASIC timing.

🔧

Custom Bus Bridges and Protocol Converters

When a designer needs to bridge PCI, VME, ISA or proprietary backplane buses to a modern processor, the EP20K100EFC324-2X's 246 user I/Os and MultiVolt I/O make it an ideal bus-translation engine. The 4,160 logic cells can implement master/target state machines for both buses simultaneously, while the 53,248-bit embedded RAM acts as a shared mailbox and FIFO buffer between the two domains. Bus-bridge designs that need more logic capacity can drop in the EP20K200EFC324-2X on the same FBGA-324 footprint. This keeps the PCB layout fixed while doubling the available logic resources for higher-throughput bridge designs.

📡

DSP Coprocessor Front-End

The EP20K100EFC324-2X serves as a DSP front-end that pre-processes data streams before handing them to a host DSP or microprocessor. Its 4,160 logic cells and fast carry chains perform FIR filters, FFT butterflies and CORDIC rotations at rates that complement a software DSP running control loops. The 53,248-bit embedded RAM holds twiddle-factor tables and sample buffers, eliminating external memory fetches on each clock cycle. The 246 I/Os simultaneously connect to multiple ADC/DAC channels and the host processor's external memory interface, making this FPGA a cost-effective co-processor for mid-rate signal-processing designs.

🔌

Legacy PCI Interface Card Designs

The EP20K100EFC324-2X is a natural fit for legacy 32-bit/33 MHz PCI interface cards because its 246 user I/Os and MultiVolt 3.3 V I/O banks can talk directly to a PCI bus without external transceivers. The 4,160 logic cells hold the PCI target/master state machine, configuration-space registers and interrupt logic in a single device, while the 53,248-bit embedded RAM provides DMA descriptor rings and small payload buffers. Although PCI has been superseded by PCIe in new designs, thousands of industrial, instrumentation and test cards still ship with this FPGA because of its deterministic 33 MHz timing and proven Quartus II IP library.

What is the EP20K100EFC324-2X and what family does it belong to?
The EP20K100EFC324-2X is a 100,000-gate Field Programmable Gate Array from the Altera APEX 20KE family. According to the Altera device-family datasheet, it contains 4,160 logic cells, 53,248 bits of embedded RAM and 416 LABs/CLBs, all packaged in a 324-ball FBGA. It operates from a 1.8 V core supply and supports up to 250 MHz internal clock rates in the -2X speed grade.
How many user I/O pins does the EP20K100EFC324-2X have?
The EP20K100EFC324-2X exposes up to 246 user I/O pins. This figure is published on DigiKey and Mouser product listings for the Altera APEX 20KE family and matches the FBGA-324 ballout. Note that 246 is the maximum I/O count for this device - actual usable I/O depends on the user's Quartus pin-out assignment and chosen configuration scheme.
What is the difference between EP20K100EFC324-2X and EP20K100EFC324-2?
Both parts share the same 324-ball FBGA package, 100K-gate die and 246 user I/O count. The -2X speed grade delivers approximately 35% faster design performance than the base -2 grade (per Altera APEX 20KE device-family literature). Otherwise they are pin-for-pin compatible: a -2 design will run on a -2X device, while the -2X part simply offers more timing margin.
What is the core voltage and I/O voltage of the EP20K100EFC324-2X?
The EP20K100EFC324-2X uses a 1.8 V core supply (VCCINT). Its I/O banks support Altera's MultiVolt interface, allowing 1.8 V, 2.5 V, or 3.3 V on VCCIO banks. This lets the device bridge to 3.3 V legacy peripherals while keeping the core running at the lower 1.8 V rail, which simplifies mixed-voltage PCB designs common in telecom line cards.
Is the EP20K100EFC324-2X still in production or recommended for new designs?
The EP20K100EFC324-2X is classified as Not Recommended for New Designs (NRND) by Intel / Altera. The APEX 20KE family was superseded by the Cyclone and Stratix device families. Engineers starting new designs should select a Cyclone IV/V or Stratix equivalent; existing designs can continue to source this part from authorized distributors while inventory lasts.
Where can I download the EP20K100EFC324-2X datasheet PDF?
The Altera APEX 20KE family datasheet (document A-APEX20KE-02, 117 pages) is hosted on Alldatasheet at the Alldatasheet EP20K100EFC324 search page. Intel / Altera's official documentation portal at intel.com also retains historical APEX 20KE handbooks, configuration device guides, and pin-out tables. A free Altera Quartus II design tool (legacy version) is required for programming.
What is the pinout of the EP20K100EFC324-2X package?
The EP20K100EFC324-2X uses a 324-ball FineLine BGA (FBGA) with 1.27 mm ball pitch on a 19x19 mm body. The full ball-to-signal assignment is published in the Altera APEX 20KE device handbook, chapter 'Package Information'. Because this is a high-density BGA, engineers typically use the Intel / Altera pin-out .csv file inside Quartus II rather than reading the diagram by hand.
What is the best drop-in replacement for the EP20K100EFC324-2X?
There is no exact drop-in replacement on the open market because the APEX 20KE family uses a unique MegaLAB architecture and configuration scheme. The closest same-package, same-family alternatives are other APEX 20KE speed grades such as EP20K100EFC324-2 (slower but pin-compatible) and the EP20K200EFC324 series for higher gate count. For new designs, Intel recommends migrating to a Cyclone IV E or Cyclone V device with a fresh PCB layout.
What is the current price of the EP20K100EFC324-2X?
As of 2026-09-07, the EP20K100EFC324-2X lists for roughly USD 185 per unit at qty 1 on the open distributor market, dropping to about USD 99.50 per unit at qty 1000. Pricing varies across 16 distributors on Octopart; live stock should be checked at DigiKey, Mouser and Avnet because the part is NRND and supply is increasingly constrained.
Where can I buy the EP20K100EFC324-2X online?
Authorized distributors currently listing the EP20K100EFC324-2X include DigiKey (DigiKey part 763689), Mouser, Octopart-aggregated stockists and brokers such as AIChipLink, Jotrin and Veswin Electronics. Because the part is NRND, brokers typically hold larger inventory than franchised distributors; always verify lot date code and RoHS status before purchase.
What is the lead time for the EP20K100EFC324-2X?
Lead time for the EP20K100EFC324-2X varies sharply because the part is NRND. As of 2026-09-07, franchised distributors such as DigiKey and Mouser list factory lead times of 12-20 weeks or NRND-style quote-only terms; broker inventory on Octopart typically ships in 1-3 days but at premium pricing. For new production, plan a Cyclone-family migration instead of relying on long-term APEX 20KE supply.
EP20K100EFC324-2X vs EP20K200EFC324-2X - which should I choose?
Choose the EP20K100EFC324-2X if your design fits within 100K system gates, 4,160 logic cells and 246 user I/Os - it is the lower-cost option. Choose the EP20K200EFC324-2X if you need 200K gates, more logic cells and more embedded RAM for denser logic or larger memory buffers. Both parts share the same FBGA-324 (19x19 mm) ballout, so the EP20K200EFC324-2X is a drop-in upgrade path on the same PCB.
Is the EP20K100EFC324-2X suitable for new industrial designs in 2026?
The EP20K100EFC324-2X is not recommended for new industrial designs in 2026 because of its NRND status and limited long-term supply. For new industrial designs, choose a current Intel / Altera Cyclone IV E, Cyclone 10 LP, or MAX 10 device instead; they provide similar logic capacity at lower power, with active lifecycle support and modern toolchains. The APEX 20KE part remains useful only for maintaining legacy equipment.
What configuration memory does the EP20K100EFC324-2X use?
The EP20K100EFC324-2X is SRAM-based, so its configuration must be loaded on every power-up. It supports four configuration schemes: passive serial, passive parallel, JTAG (IEEE 1149.1), and Altera configuration EPROMs (EPC devices). Designers typically pair it with an EPC2 or EPC8 configuration EPROM for stand-alone board bring-up, or program it via JTAG during development.
What are the key specifications of EP20K100EFC324-2X that engineers should know?
The five most important specifications are: (1) 100,000 system gates / 4,160 logic cells, (2) 246 maximum user I/O pins, (3) 53,248 bits of embedded RAM, (4) 1.8 V core with MultiVolt I/O supporting 1.8 / 2.5 / 3.3 V, and (5) a 324-ball FBGA package with 1.27 mm pitch on a 19x19 mm body. Together these define the device's logic capacity, I/O flexibility and PCB integration footprint.

엔지니어링 참조 데이터: EP20K100EFC324-2X — 비교, 설계 지침 및 규정 준수 정보.

선택 가이드

Choose the EP20K100EFC324-2X when you need 100K system gates and 246 user I/Os in a 324-ball FBGA, with the fastest available APEX 20KE speed grade (-2X) for high-margin 250 MHz designs. Choose the EP20K100EFC324-2 instead if you can accept ~35% lower timing margin and want a lower price. Choose the EP20K200EFC324-2X if your design exceeds 4,160 logic cells but still fits the FBGA-324 footprint - it is a drop-in upgrade. Avoid choosing this part for new production in 2026 - the APEX 20KE family is NRND; new designs should target Intel / Altera Cyclone IV E or Cyclone 10 LP instead, and reserve the APEX 20KE family for legacy maintenance.

대체품과의 비교

파라미터 이 제품 EP20K100EFC324-2 EP20K200EFC324-2X EP20K100EFC324-1N
Brand Intel / Altera Intel / Altera Intel / Altera Intel / Altera
Package 324-ball FBGA (19x19 mm) 324-ball FBGA (19x19 mm) - same 324-ball FBGA (19x19 mm) - same 324-ball FBGA (19x19 mm) - same
System Gates 100K 100K 200K 100K
Logic Cells / Elements 4,160 4,160 8,320 4,160
Maximum User I/Os 246 246 246 246
Embedded RAM Bits 53,248 53,248 106,496 53,248
Core Voltage 1.8 V 1.8 V 1.8 V 1.8 V
Speed Grade -2X (fastest) -2 (slower) -2X -1N (industrial temp)
Lifecycle Status NRND NRND NRND NRND

주요 차별점

  • Highest speed grade in the APEX 20KE 100K-gate family (vs EP20K100EFC324-2)
  • Highest logic density in the same FBGA-324 footprint (vs EP20K100EFC324-1N)
  • Lower-density, lower-cost option on the same FBGA-324 footprint (vs EP20K200EFC324-2X)

설계 노트

The APEX 20KE family uses 1.8 V VCCINT but its I/O banks support 1.8 V / 2.5 V / 3.3 V on VCCIO - mixing the wrong bank voltage is a common bring-up failure. Always check the Quartus II 'Device and Pin Options' report to confirm VCCIO bank assignments before powering the board, and verify that no pin is configured for an I/O standard whose voltage is not present on that bank. Estimated power dissipation for a 50% utilization, 250 MHz design is roughly 0.8 W from VCCINT and another 0.1-0.3 W from VCCIO, depending on toggle rate.

The 324-ball FBGA package has a junction-to-ambient thermal resistance (θJA) in the 25-35 °C/W range when mounted on a JEDEC 4-layer test board with adequate thermal vias. For continuous operation near 250 MHz with high toggle rates, place a thermal-via array directly under the package center pad and stitch copper pours on inner layers. Estimated: at 1.0 W total dissipation and 30 °C/W θJA, junction temperature rises 30 °C above ambient, so an 85 °C commercial-grade device hits its junction limit at 55 °C ambient without thermal management.

Route the 324-ball FBGA (1.27 mm pitch, 19x19 mm body) on a PCB stack-up that supports microvias or via-in-pad to escape inner balls. Use 0.10 mm (4 mil) trace width with 0.10 mm spacing on the top layer for escape routing, and place a 6x6 thermal-via array under the central ground balls. Keep all VCCINT and VCCIO decoupling capacitors within 5 mm of their respective balls, with a 0.1 µF / 1 µF / 10 µF value stack to cover high-frequency and bulk current transients.

규정 준수 정보

RoHS
Unknown
REACH
Unknown
AEC-Q100
Not Applicable
무연
Unknown
무할로겐
Unknown
분쟁 광물
Unknown

RoHS, REACH, lead-free and halogen-free status for the EP20K100EFC324-2X were not in the provided verified web data; confirm with the lot-specific manufacturer documentation before shipping into regulated markets. AEC-Q100 does not apply because this is a commercial-grade FPGA, not an automotive-qualified part.

데이터 검증일: 2026-09-07 — XAIPART 부품 엔지니어링 팀이 검증하고 관리한 데이터

관련 검색

EP20K100EFC324-2X EP20K100EFC324-2X datasheet Altera APEX 20KE 100K FPGA EP20K100EFC324-2X price Intel APEX 20KE FBGA-324 EP20K100EFC324-2X drop-in replacement EP20K100EFC324-2X pinout FBGA APEX 20KE NRND migration EP20K100EFC324-2X vs EP20K200EFC324-2X where to buy EP20K100EFC324-2X what is the operating frequency of EP20K100EFC324-2X EP20K100EFC324-2X lead time stock APEX 20KE telecom line card FPGA Cyclone IV replacement for APEX 20KE

관련 부품 & 용어

Intel Altera EP20K100EFC324-2X APEX 20KE FPGA Field Programmable Gate Array PLD Programmable Logic Device SPLD logic cell LAB CLB MegaLAB Embedded Array Block EAB embedded RAM MultiVolt I/O JTAG IEEE 1149.1 Quartus II FBGA BGA fine-pitch BGA 1.27 mm ball pitch surface mount NRND RoHS configuration EPROM EPC2LC20
빠른 견적 RFQ
상세 정보를 모두 입력하십시오 — 영업팀이 24시간 이내에 답변드립니다
부품 번호 제조사 패키지 QTY 목표 가격 합계
합계: $0.00 USD
✓
견적이 제출되었습니다!

24시간 이내에 이메일로 답변드리겠습니다

1
RFQ 제출됨
2
견적 접수됨
3
주문 완료
4
결제
5
배송됨
6
배송 완료
RFQ 상세 보기