at24c21 ATMEL Corporation, at24c21 Datasheet
at24c21
Available stocks
Related parts for at24c21
at24c21 Summary of contents
Page 1
... VCLK pin. The Bidirectional Mode is selected by a valid high-to-low transition on the SCL pin and offers byte selectable read/write capability of the entire memory array. The AT24C21 is available in space saving 8-lead PDIP and 8-lead JEDEC SOIC packages. Pin Configurations ...
Page 2
... Storage Temperature .................................... - +150 C Voltage on Any Pin with Respect to Ground .....................................-1.0V to +7.0V Maximum Operating Voltage .......................................... 6.25V DC Output Current........................................................ 5.0 mA Block Diagram AT24C21 2 *NOTICE: Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent dam- age to the device. This is a stress rating only and ...
Page 3
... SERIAL CLOCK (VCLK): Upon power-up, the device is in the Transmit-only mode and will transmit the entire memory contents via the SDA pin with positive signals on the VCLK pin. AT24C21, 1K SERIAL EEPROM: Internally organized with 128 pages of one byte each. The 1K requires a 7-bit data word address for random word addressing ...
Page 4
... F t Stop Set-up Time SU.STO t Data Out Hold Time DH t Write Cycle Time WR (1) Endurance 5.0V, 25°C, Page Mode Note: 1. This parameter is characterized and is not 100% tested. AT24C21 (1) (SDA and SCL pins) 2.5-volt Min Max 500 4.0 4.7 500 0 = +2.5V to +5.5V C ...
Page 5
... Bidirectional Mode, there is no way to return to the Transmit-only Mode, except to power down (reset) the device. The AT24C21 will power up in the Transmit-only Mode. In this mode, the device will out- put one bit of data on the SDA pin on each rising edge on the VCLK pin. Data is transmitted in 8 bit words with the most significant bit first. Each word is followed by a 9th “ ...
Page 6
... Figure 1. Transmit-only Mode Figure 2. Device Initialization for Transmit-only Mode AT24C21 6 0405I–SEEPR–7/03 ...
Page 7
... EEPROM in 8-bit words. The EEPROM sends a zero to acknowledge that it has received each word. This happens during the ninth clock cycle. The AT24C21 requires an 8-bit device address word following a start condition to enable the chip for a read or write operation (refer to Figure 4). The device address word consists of a mandatory one, zero sequence for the first four most significant bits as shown. This is common to all the EEPROM devices. The next three bits are don’ ...
Page 8
... SCL: Serial Clock, SDA: Serial Data I/O SCL SDA 8th BIT WORDn Note: The write cycle time t is the time from a valid stop condition of a write sequence to the end of the internal clear/write cycle. WR AT24C21 8 ACK ( STOP CONDITION CONDITION START 0405I–SEEPR–7/03 ...
Page 9
... Data Validity Start and Stop Definition Output Acknowledge 0405I–SEEPR–7/03 AT24C21 9 ...
Page 10
... Mode, the entire memory is protected and becomes ROM only. This protects the device memory from any inadvertent write operations. NOISE PROTECTION: Special internal circuitry placed on the SDA and SCL pins pre- vent small noise spikes from activating the device. Furthermore, the AT24C21 employs a low V detector circuit which disables the erase\write logic whenever ...
Page 11
... The sequential read operation is terminated when the microcontroller does not respond with a zero but does generate a following stop condi- tion (refer to Figure 9). AT24C21 11 ...
Page 12
... Figure 4. Device Address Figure 5. Byte Write Figure 6. Page Write (*=Don’t care bits) AT24C21 12 0405I–SEEPR–7/03 ...
Page 13
... Figure 7. Current Address Read Figure 8. Random Read Figure 9. Sequential Read (*=Don’t care bits) 0405I–SEEPR–7/03 AT24C21 13 ...
Page 14
... Ordering Information Ordering Code AT24C21-10PI-2.5 AT24C21-10SI-2.5 8P3 8-lead, 0.300" Wide, Plastic Dual Inline Package (PDIP) 8S1 8-lead, 0.150" Wide, Plastic Gull Wing Small Outline (JEDEC SOIC) -2.5 Low Voltage (2.5V to 5.5V) AT24C21 14 Package 8P3 8S1 Package Type Options Operation Range Industrial (- 0405I–SEEPR–7/03 ...
Page 15
... Dambar protrusions. Dambar protrusions shall not exceed 0.010 (0.25 mm). 2325 Orchard Parkway San Jose, CA 95131 R 0405I–SEEPR–7/ TITLE 8P3, 8-lead, 0.300" Wide Body, Plastic Dual In-line Package (PDIP) AT24C21 End View COMMON DIMENSIONS (Unit of Measure = inches) SYMBOL MIN NOM MAX A 0.210 A2 0.115 0.130 ...
Page 16
... Side View End View Note: This drawing is for general information only. Refer to JEDEC Drawing MS-012 for proper dimensions, tolerances, datums, etc. 2325 Orchard Parkway San Jose, CA 95131 R AT24C21 TITLE 8S1, 8-lead (0.150" Wide Body), Plastic Gull Wing ...
Page 17
... Fax: (81) 3-3523-7581 Disclaimer: Atmel Corporation makes no warranty for the use of its products, other than those expressly contained in the Company’s standard warranty which is detailed in Atmel’s Terms and Conditions located on the Company’s web site. The Company assumes no responsibility for any errors which may appear in this document, reserves the right to change devices or specifications detailed herein at any time without notice, and does not make any commitment to update the information contained herein ...