購買 LM2904DRG4 | LM2904DRG4數據表 | Heisener.com
聯繫我們
SalesDept@heisener.com 86-755-83210559-841
登入/註冊
BOM
購物車 0

LM2904DRG4

hot LM2904DRG4

LM2904DRG4

僅供參考

零件編號 LM2904DRG4
製造商 Texas Instruments
描述 IC OPAMP GP 700KHZ 8SOIC
數據表
封裝 8-SOIC (0.154", 3.90mm Width)
ECAD
庫存 151,716 piece(s)
單價 $ 0.1157 *
交貨期 可立即發貨
預計送達時間 十一月 25 - 十一月 30 (選擇速遞服務)
請求報價
支付方式
送貨服務
  • 我們提供的 LM2904DRG4 具有全球市場競爭力的價格，如有需要請發送詢價單給我們。謝謝！
  • 添加 LM2904DRG4 及其數量至BOM以便提交您的報價請求。 Heisener.com 無需註冊便可以提交 LM2904DRG4 的報價請求。

LM2904DRG4參數

製造商Texas Instruments
類別積體電路 (IC) - 線性 - 放大器 - 儀表、運算放大器、緩衝放大器
封裝8-SOIC (0.154", 3.90mm Width)
ECAD
系列-
放大器類型General Purpose
電路數量2
輸出類型-
擺率0.3 V/µs
增益帶寬產品700kHz
-3db帶寬-
電流 - 輸入偏差20nA
電壓 - 輸入偏移3mV
供電1mA
電流 - 輸出/通道30mA
電壓 - 電源，單/雙（±）3 V ~ 26 V, ±1.5 V ~ 13 V
工作溫度-40°C ~ 125°C
安裝類型Surface Mount
包/箱8-SOIC (0.154", 3.90mm Width)
供應商設備包8-SOIC

LM2904DRG4 Packaging

Customized Labels
Sealing
Packing
Insepction

LM2904DRG4 FAQ

  • 1. How to order LM2904DRG4 on Heisener?
    Currently, Heisener only provide peer-to-peer order processing. While you submit the RFQ, our professional agent will contact you with the competitive prices in the global market, and our agent will prompt you to finish the order if you accept our offers.
  • 2. How does Heisener guarantee that LM2904DRG4 is from the original manufacturer or authorized agents?
    We have a professional and experienced quality control team to strictly verify and test the LM2904DRG4. All suppliers must pass our qualification reviews before they can publish their products including LM2904DRG4 on Heisener; we pay more attention to the channels and quality of LM2904DRG4 products than any other customer. We strictly implement supplier audits, so you can purchase with confidence.
  • 3. Are the LM2904DRG4 price and inventory displayed accurate?
    The price and inventory of LM2904DRG4 fluctuates frequently and cannot be updated in time, it will be updated periodically within 24 hours. And, our quotation usually expires after 5 days.
  • 4. What forms of payment are accepted?
    Wire Transfer, PayPal, Alipay, Wechat, Credit Card, Western Union, MoneyGram, and Escrow are all acceptable.
    Warm Tips: Some orders in certain payment forms may require handling fee.
  • 5. How is the shipping arranged?
    Customers can choose industry-leading freight companies, including DHL, UPS, FedEx, TNT, and Registered Mail. Shipping insurance is also available.
    Once your order has been processed for shipment, our salesperson will send you an email advising you of the shipping status and tracking number.
    Warm Tips: It may take up to 24 hours for the carriers to display tracking information. Usually, express delivery takes 3-5 days, and registered mail takes 25-60 days.
  • 6. What is the process for return or replacement of LM2904DRG4?
    All goods will implement Pre-Shipment Inspection (PSI), selected at random from all batches of your order to do a systematic inspection before arranging the shipment. If there is something wrong with the LM2904DRG4 we delivered, we will accept the replacement or return of the LM2904DRG4 only when all of the below conditions are fulfilled:
    (1)Such as a deficiency in quantity, delivery of wrong items, and apparent external defects (breakage and rust, etc.), and we acknowledge such problems.
    (2)We are informed of the defect described above within 90 days after the delivery of LM2904DRG4.
    (3)The PartNo is unused and only in the original unpacked packaging.
    Two processes to return the products:
    (1)Inform us within 90 days
    (2)Obtain Requesting Return Authorizations
  • 7.How to contact us to get technical supports, such as LM2904DRG4 pin diagram, LM2904DRG4 datasheet?
    If you need any after-sales service, please do not hesitate to contact us.

LM2904DRG4相關產品

520R25HT13M0000 520R25HT13M0000 CTS-Frequency Controls, OSC TCXO 13.000MHZ CLP SNWV SMD, 4-SMD, No Lead, - 查看
1206Y1000333MXRE03 1206Y1000333MXRE03 Knowles Syfer, CERAMIC CAP, 1206 (3216 Metric), - 查看
H7N1002LS-E H7N1002LS-E Renesas Electronics America, MOSFET N-CH 100V LDPAK, SC-83, - 查看
hotREF194ESZ REF194ESZ Analog Devices Inc., IC VREF SERIES 4.5V 8SOIC, 8-SOIC (0.154", 3.90mm Width), - 查看
ATSAM4C8CA-AUR ATSAM4C8CA-AUR Microchip Technology, IC MCU 32BIT 512KB FLASH 100LQFP, 100-LQFP, - 查看
NB6L611MNR2G NB6L611MNR2G ON Semiconductor, IC CLK BUFFER 1:2 4GHZ 16QFN, 16-VFQFN Exposed Pad, - 查看
ARJ11B-MESBQ-A-B-EMU2 ARJ11B-MESBQ-A-B-EMU2 Abracon LLC, CONN MAGJACK 1PORT 100 BASE-T, -, - 查看
1404513 1404513 Phoenix Contact, CONN MOD COUPLER 8P8C TO 8P8C, -, - 查看
KJB7T15F19JE KJB7T15F19JE ITT Cannon, LLC, CONN RCPT 19POS JAM NUT SKT, -, - 查看
PT01E18-5S-SR PT01E18-5S-SR Amphenol Industrial Operations, PT 5C 5#12 SKT RECP, -, - 查看
AMM22DRUI AMM22DRUI Sullins Connector Solutions, CONN EDGE DUAL FMALE 44POS 0.156, -, - 查看
RDC3072D12 RDC3072D12 XP Power, DC/DC CONVERTER +/-12V 30W, 7-DIP Module, 6 Leads, - 查看

LM2904DRG4 保證

Service Guarantee

服務保證

我們保證100％的客戶滿意度。

我們經驗豐富的銷售團隊和技術支持團隊支持我們的服務以滿足所有客戶。

Quality Guarantee

質量保證

我們提供90天保修。

如果您收到的物品質量不合格，我們將負責您的退款或更換，但物品必須以原始狀態退回。

全球供應鏈-可靠的授權分銷商資源

零件編號 製造商 描述 庫存

LM2904DRG4

D# V36:1790_07270801

 Texas Instruments

Op Amp Dual GP ±13V/26V 8-Pin SOIC T/R

RoHS: Compliant
 0

LM2904DR

D# V72:2272_07270798

 Texas Instruments

Op Amp Dual GP ±13V/26V 8-Pin SOIC T/R

RoHS: Compliant
 0

LM2904D

D# E02:0323_00212356

 STMicroelectronics

Op Amp Dual Low Power Amplifier ±15V/30V 8-Pin SO N Tube

RoHS: Compliant
 0
零件編號 製造商 描述 庫存

LM2904D

D# LM2904D

 Texas Instruments

OP Amp Dual GP ±13V/26V 8-Pin SOIC Tube - Rail/Tube (Alt: LM2904D)

 0
零件編號 製造商 描述 庫存

LM2904D

D# LM2904D

 STMicroelectronics

OP Amp Dual GP ±15V/30V 8-Pin SO N Tube (Alt: LM2904D)

 0

LM2904DR

D# LM2904DR

 ROHM Semiconductor

OP Amp Dual GP ±16V/32V 8-Pin SOIC T/R (Alt: LM2904DR)

 0
零件編號 製造商 描述 庫存

LM2904D

 Texas Instruments

STOCK

 83
零件編號 製造商 描述 庫存

LM2904D

 Philips Semiconductors

8070

LM2904DRG4

 Texas Instruments

2312

LM2904DR

 Texas Instruments

15823
零件編號 製造商 描述 庫存

LM2904D

D# 41S5865

 STMicroelectronics

Op Amp Dual GP 13V/26V 8-Pin

 432
零件編號 製造商 描述 庫存

LM2904DRG4

 Texas Instruments

- Tape and Reel

 300000

LM2904D

 STMicroelectronics

STMicroelectronics LM2904DT

 1470

LM2904DG4

 Texas Instruments

OP AMP, 700KHZ, 0.3V/uS, SOIC-8, Op Amp Type:High Gain, No. of Amplifiers:2, Slew Rate:0.3V/s, Supply Voltage Range: 1.5V to 13V, Amplifier Case Style:SOIC, No. of Pins:8, Bandwidth:700kHz, Operating Temperature Min:-40C , RoHS Compliant: Yes

 0

LM2904DR

 Texas Instruments

- Tape and Reel

 300000
零件編號 製造商 描述 庫存

LM2904DR

D# C1S746200151358

 Texas Instruments

OP Amp Dual GP }13V/26V 8-Pin SOIC T/R

RoHS: Not Compliant
Min Qty: 25
Container: Bulk
 30

LM2904D

D# C1S746200051687

 Texas Instruments

OP Amp Dual GP 13V/26V 8-Pin SOIC Tube

RoHS: Not Compliant
pbFree: No
Min Qty: 10
Container: Bulk
 133
零件編號 製造商 描述 庫存

LM2904DR

 Texas Instruments

General Purpose 2 3V ~ 26V, ±, 1.5V ~ 13V 1mA 700kHz 0.3 V/us SOIC-8_150mil General Purpose Amplifiers RoHS

 2285

LM2904DRG4

 Texas Instruments

SOIC-8 General Purpose Amplifiers RoHS

 2485
零件編號 製造商 描述 庫存

LM2904D

 STMicroelectronics

RoHS: Compliant
 0

LM2904DR

 Texas Instruments

RoHS: Compliant
 0
零件編號 製造商 描述 庫存

LM2904DR

 Texas Instruments

RoHS (ship within 1day) - D/C 2018

 489
零件編號 製造商 描述 庫存

LM2904D

D# 2156-LM2904D-ON-ND

 Rochester Electronics LLC

IC GP OPAMP 2 CIRCUIT 8SO

 28723

LM2904DRG4

D# 296-39004-1-ND

 Texas Instruments

IC OPAMP GP 2 CIRCUIT 8SOIC

 1547

LM2904DG4

D# 296-52893-ND

 Texas Instruments

IC OPAMP GP 2 CIRCUIT 8SOIC

 4988

LM2904DR

D# 296-14596-2-ND

 Texas Instruments

IC OPAMP GP 2 CIRCUIT 8SOIC

 6000
零件編號 製造商 描述 庫存

LM2904DR

D# LM2904DR

 National Semiconductor Corporation

Industry Leading ISO:9001/AS9120A Stocking Distributor of Obsolete & Hard to Find IC's/Semi's, Specializing in Altera/Xilinx. In-House Counterfeit Detection Lab. In Business 20 Years. Free Shipping on Orders Over $250. Buy American, Buy Direct

 2982

LM2904DRG4

D# LM2904DRG4

 National Semiconductor Corporation

Industry Leading ISO:9001/AS9120A Stocking Distributor of Obsolete & Hard to Find IC's/Semi's, Specializing in Altera/Xilinx. In-House Counterfeit Detection Lab. In Business 20 Years. Free Shipping on Orders Over $250. Buy American, Buy Direct

 1230

LM2904D

D# LM2904D

 National Semiconductor Corporation

Industry Leading ISO:9001/AS9120A Stocking Distributor of Obsolete & Hard to Find IC's/Semi's, Specializing in Altera/Xilinx. In-House Counterfeit Detection Lab. In Business 20 Years. Free Shipping on Orders Over $250. Buy American, Buy Direct

 1574
零件編號 製造商 描述 庫存

LM2904DRG4

 Texas Instruments

In stock shipping within 2days

 388

LM2904D

 STMicroelectronics

In stock shipping within 2days

 32049
零件編號 製造商 描述 庫存

LM2904D

D# 3117027

 Texas Instruments

OP AMP, DUAL IND SPEC, 2904, SOIC8

RoHS: Compliant
Min Qty: 5
Container: Each
 111

LM2904DRG4

D# 3117033RL

 Texas Instruments

OP-AMP, DUAL, 700KHZ, 0.3V/US, SOIC-8

RoHS: Compliant
Min Qty: 5
Container: Reel
 0

LM2904DR

D# 3004619

 Texas Instruments

OP-AMP, 700KHZ, 0.3V/US, SOIC-8

RoHS: Compliant
Min Qty: 5
Container: Cut Tape
 0

LM2904DRG4 .

D# 2769244RL

 Texas Instruments

OP-AMP, DUAL, 700KHZ, 0.3V/US, SOIC-8

RoHS: Compliant
Min Qty: 5
Container: Reel
 0
零件編號 製造商 描述 庫存

LM2904D

 STMicroelectronics

STOCK, SAME DAY SHIPPING. ALL PARTS ARE NEW

 40
零件編號 製造商 描述 庫存

LM2904DR

 ROHM Semiconductor

RoHS: Compliant
pbFree: Yes
 0
零件編號 製造商 描述 庫存

LM2904DG4

 Texas Instruments

OEM/CM QUOTES ONLY | NO BROKERS

 232

LM2904DR

 ON Semiconductor

OEM/CM QUOTES ONLY | NO BROKERS

 2900006

LM2904D

 ON Semiconductor

OEM/CM QUOTES ONLY | NO BROKERS

 632206

LM2904DRG4

 Texas Instruments

OEM/CM QUOTES ONLY | NO BROKERS

 69600
零件編號 製造商 描述 庫存

LM2904DRG4TI10

 Texas Instruments

OEM/CM ONLY

 705

LM2904DG4

 Texas Instruments

OEM/CM ONLY

 617

LM2904DRG4

 Texas Instruments

OEM/CM ONLY

 442

LM2904DRG4CN

 Texas Instruments

OEM/CM ONLY

 805
零件編號 製造商 描述 庫存

LM2904D

 NXP Semiconductors

2000
零件編號 製造商 描述 庫存

LM2904D

 ON Semiconductor

In stock

 162
零件編號 製造商 描述 庫存

LM2904DR

 Texas Instruments

General Purpose Amplifier Circuit - 8-SOIC

RoHS: Compliant
 10000
零件編號 製造商 描述 庫存

LM2904DR

D# C7934

 Texas Instruments

1860

LM2904DRG4

D# C350546

 Texas Instruments

2475
零件編號 製造商 描述 庫存

LM2904DRG4

 Texas Instruments

in stock - can ship the same day

 63

LM2904DR

 Texas Instruments

in stock - can ship the same day

 465

LM2904D

 Philips Semiconductors

in stock - can ship the same day

 1437
零件編號 製造商 描述 庫存

LM2904D

 Texas Instruments

IC OP AMPS 700KHZ 30mA 8-SOIC

 0
零件編號 製造商 描述 庫存

LM2904DR

 Texas Instruments

OEM/CM Immediate delivery

 44858

LM2904DRG4

 Texas Instruments

OEM/CM Immediate delivery

 288

LM2904D

 STMicroelectronics

OEM/CM Immediate delivery

 31534
零件編號 製造商 描述 庫存

LM2904DRG4

D# 595-LM2904DRG4

 Texas Instruments

Operational Amplifiers - Op Amps Dual General-Purpose Op Amp

RoHS: Compliant
 3493

LM2904DR

D# 595-LM2904DR

 Texas Instruments

Operational Amplifiers - Op Amps Dual GP Op Amp

RoHS: Compliant
 4021

LM2904D

D# 595-LM2904D

 Texas Instruments

Operational Amplifiers - Op Amps Dual General Purpose

RoHS: Compliant
 2175

LM2904DG4

D# 595-LM2904DG4

 Texas Instruments

Operational Amplifiers - Op Amps Dual General-Purpose Op Amp

RoHS: Compliant
 1917
零件編號 製造商 描述 庫存

LM2904D

D# LM2904D

 National Semiconductor Corporation

IC DUAL OP-AMP SO-8

 110
零件編號 製造商 描述 庫存

LM2904DRG4

D# 52AH7173

 Texas Instruments

OP-AMP, DUAL, 700KHZ, 0.3V/US, SOIC-8, No. of Amplifiers:2 Amplifier, Bandwidth:700kHz, Slew Rate:0.3V/µs, Supply Voltage Range:3V to 26V, Amplifier Case Style:SOIC, No. of Pins:8Pins, Operating Temperature Min:-40°C, Operating RoHS Compliant: Yes

RoHS: Compliant
Min Qty: 5
Container: Cut Tape
 4775

LM2904DR

D# 64AH3841

 Texas Instruments

OP-AMP, 700KHZ, 0.3V/US, SOIC-8, No. of Amplifiers:2 Amplifier, Bandwidth:700kHz, Slew Rate:0.3V/µs, Supply Voltage Range:± 1.5V to ± 13V, Amplifier Case Style:SOIC, No. of Pins:8Pins, Operating Temperature Min:-40°C, Operating RoHS Compliant: Yes

RoHS: Compliant
Min Qty: 2500
Container: TAPE & REEL - FULL
 27500

LM2904D

D# 06F9184

 Texas Instruments

OP AMP, 700KHZ, 0.3V/uS, SOIC-8, No. of Amplifiers:2 Amplifier, Bandwidth:700kHz, Slew Rate:0.3V/µs, Supply Voltage Range:± 1.5V to ± 13V, Amplifier Case Style:SOIC, No. of Pins:8Pins, Operating Temperature Min:-40°C, Product Range:-RoHS Compliant: Yes

RoHS: Compliant
Min Qty: 1
Container: Bulk
 725
零件編號 製造商 描述 庫存

LM2904DRG4

D# NS-LM2904DRG4

 Texas Instruments

OEM/CM ONLY

 2921

LM2904D

D# NS-LM2904D

 Texas Instruments

OEM/CM ONLY

 5570

LM2904DG4

D# NS-LM2904DG4

 Texas Instruments

OEM/CM ONLY

 9367

LM2904DR

D# NS-LM2904DR

 Texas Instruments

OEM/CM ONLY

 14875
零件編號 製造商 描述 庫存

LM2904DR

 Texas Instruments

Operational Amplifier, Dual AMP, Bipolar, 8 Pin, Plastic, SOP

 4403

LM2904D

 STMicroelectronics

Operational Amplifier, Dual AMP, Bipolar, 8 Pin, Plastic, SOP

 24000

LM2904DG4

 Texas Instruments

DUAL OP-AMP, 10000 uV OFFSET-MAX, 0.7 MHz BAND WIDTH, PDSO8

 200

LM2904DRG4

 Texas Instruments

DUAL OP-AMP, 10000 uV OFFSET-MAX, 0.7 MHz BAND WIDTH, PDSO8

 1278
零件編號 製造商 描述 庫存

LM2904DR

D# LM2904DR

 Texas Instruments

Semiconductor

 1770

LM2904D

D# LM2904D

 Texas Instruments

Inventory R

 1200
零件編號 製造商 描述 庫存

LM2904DR

D# 0527429

 Texas Instruments

LM2904DR Texas Instruments, Precision, Op Amp, 700kHz, 5 24 V, 8-Pin SOIC, PK

Min Qty: 25
Container: Package
 0

LM2904D

D# 5172380P

 Texas Instruments

LM2904D Texas Instruments, Precision, Op Amp, 700kHz, 5 24 V, 8-Pin SOIC, TU

Min Qty: 20
Container: Tube
 7784
零件編號 製造商 描述 庫存

LM2904DRG4

 Texas Instruments

LM2904 Dual general-purpose operational amplifier

RoHS: Compliant
 2200

LM2904D

 ON Semiconductor

LM2904 Dual general-purpose operational amplifier

RoHS: Compliant
 28723
零件編號 製造商 描述 庫存

LM2904DRG4

 Texas Instruments

OEM/CM ONLY

 10822

LM2904DG4

 Texas Instruments

OEM/CM ONLY

 266

LM2904D

 STMicroelectronics

OEM/CM ONLY

 969173

LM2904DR

 Texas Instruments

OEM/CM ONLY

 2537250
零件編號 製造商 描述 庫存

LM2904DR

 Texas Instruments

IN stock Immediate delivery

 44843

LM2904DRG4

 Texas Instruments

IN stock Immediate delivery

 283

LM2904D

 STMicroelectronics

IN stock Immediate delivery

 31519
零件編號 製造商 描述 庫存

LM2904DR

 ROHM Semiconductor

Operational Amplifiers - Op Amps 2 circuits, 3 to 26V -40 to +125 Op Temp

pbFree: Pb-Free
 0
零件編號 製造商 描述 庫存

LM2904DRG4

 Texas Instruments

2-Channel, 1 MHz, general purpose op amp for cost-sensitive systems

 0

LM2904DR

 Texas Instruments

2-Channel, 1 MHz, general purpose op amp for cost-sensitive systems

 396

LM2904D

 Texas Instruments

2-Channel, 1 MHz, general purpose op amp for cost-sensitive systems

 11
零件編號 製造商 描述 庫存

LM2904D

 STMicroelectronics

shipping today

 35996

LM2904DR

 Texas Instruments

shipping today

 65

LM2904DRG4

 Texas Instruments

shipping today

 59996
零件編號 製造商 描述 庫存

LM2904DR

D# 52370466

 Texas Instruments

Op Amp Dual GP ±13V/26V 8-Pin SOIC T/R

RoHS: Compliant
 0

LM2904D

D# 53358223

 STMicroelectronics

Op Amp Dual Low Power Amplifier ±15V/30V 8-Pin SO N Tube

RoHS: Compliant
 0
零件編號 製造商 描述 庫存

LM2904DRG4 TI10+

 Texas Instruments

RFQ

 2334

LM2904DR

 Texas Instruments

RFQ

 900
零件編號 製造商 描述 庫存

LM2904D

 Texas Instruments

IC OPAMP GP 700KHZ 8SOIC

 71144

LM2904DR

 Texas Instruments

IC OPAMP GP 700KHZ 8SOIC

 578095
零件編號 製造商 描述 庫存

LM2904D

D# 3117027

 Texas Instruments

OP AMP, DUAL IND SPEC, 2904, SOIC8

RoHS: Compliant
Min Qty: 5
Container: Each
 111

LM2904DRG4

D# 3117033

 Texas Instruments

OP-AMP, DUAL, 700KHZ, 0.3V/US, SOIC-8

RoHS: Compliant
Min Qty: 1
Container: Cut Tape
 4775

LM2904DR

D# 3004619

 Texas Instruments

OP-AMP, 700KHZ, 0.3V/US, SOIC-8

RoHS: Compliant
Min Qty: 5
Container: Cut Tape
 0

LM2904DRG4 .

D# 2769244

 Texas Instruments

OP-AMP, DUAL, 700KHZ, 0.3V/US, SOIC-8

RoHS: Compliant
Min Qty: 1
Container: Cut Tape
 0

Quick Inquiry

LM2904DRG4

質量認證

黑森爾對質量的承諾，塑造了我們的採購、測試、運輸流程以及它們之間的每一步。這個基準是我們所銷售的每一個元器件的基礎。

ISO9001:2015, ICAS, IAF, UKAS

查看證書

聯繫我們

您有關於 LM2904DRG4 的問題嗎？

LM2904DRG4 QRCode

掃描以查看此頁面

推薦產品

XC18V04PCG44C

IC PROM REPROGR 4MB 44-PLCC

MAX3387EEUG+T

IC TXRX RS232 250KBPS 24-TSSOP

PIC16F1509-I/SS

IC MCU 8BIT 14KB FLASH 20SSOP

LTC2870IFE#PBF

IC TXRX RS232/485/422 MULTIPRTCL

SBB-5089Z

IC AMP HBT 6000MHZ SOT-89

LT6656ACDC-2.048#TRMPBF

IC VREF SERIES 2.048V 6DFN

LTM4608AMPY#PBF

IC MODULE REG DC/DC 8A 68BGA

SKY13374-397LF

IC SWITCH DPDT LF-6GHZ 12QFN

LT1763CS8-3.3#PBF

IC REG LINEAR 3.3V 500MA 8SOIC

NSR0320MW2T1G

DIODE SCHOTTKY 20V 1A SOD323

更多 »

LM2904DRG4 Tags

  • LM2904DRG4
  • LM2904DRG4 PDF
  • LM2904DRG4 數據表
  • LM2904DRG4 規格
  • LM2904DRG4 圖片
  • Texas Instruments
  • Texas Instruments LM2904DRG4
  • 買LM2904DRG4
  • LM2904DRG4 價格
  • LM2904DRG4 經銷商
  • LM2904DRG4 供應商
  • LM2904DRG4 批發

LM2904DRG4可用於