Datasheet

 1994-2012 Microchip Technology Inc. DS21095K-page 3
24LC21
TABLE 1-2: AC CHARACTERISTICS
Parameter Symbol
Standard Mode
Vcc= 4.5 - 5.5V
Fast Mode
Units Remarks
Min Max Min Max
Clock frequency F
CLK — 100 — 400 kHz —
Clock high time T
HIGH 4000 — 600 — ns —
Clock low time T
LOW 4700 — 1300 — ns —
SDA and SCL rise time T
R — 1000 — 300 ns (Note 1)
SDA and SCL fall time T
F — 300 — 300 ns (Note 1)
Start condition hold time T
HD:STA 4000 — 600 — ns After this period the first clock
pulse is generated
Start condition setup time T
SU:STA 4700 — 600 — ns Only relevant for repeated
Start condition
Data input hold time T
HD:DAT 0—0—ns(Note 2)
Data input setup time T
SU:DAT 250 — 100 — ns —
Stop condition setup time T
SU:STO 4000 — 600 — ns —
Output valid from clock T
AA — 3500 — 900 ns (Note 2)
Bus free time T
BUF 4700 — 1300 — ns Time the bus must be free
before a new transmission
can start
Output fall time from V
IH
min. to V
IL max.
T
OF — 250 20 + .1
C
B
250 ns (Note 1), CB 100 pF
Input filter spike suppres-
sion (SDA and SCL pins)
T
SP — 50 — 50 ns (Note 3)
Write cycle time T
WR — 10 — 10 ms Byte or Page mode
Transmit-only Mode Parameters
Output valid from V
CLK TVAA — 2000 — 1000 ns —
V
CLK high time TVHIGH 4000 — 600 — ns —
V
CLK low time TVLOW 4700 — 1300 — ns —
Mode transition time T
VHZ — 500 — 500 ns —
Transmit-only power-up
time
T
VPU 0—0—ns—
Endurance — 1M — 1M — cycles 25°C, V
CC = 5.0V, Block
mode (Note 4)
Note 1: Not 100% tested. C
B = total capacitance of one bus line in pF.
2: As a transmitter, the device must provide an internal minimum delay time to bridge the undefined region
(minimum 300 ns) of the falling edge of SCL to avoid unintended generation of Start or Stop conditions.
3: The combined T
SP and VHYS specifications are due to new Schmitt Trigger inputs which provide improved
noise and spike suppression. This eliminates the need for a T
I specification for standard operation.
4: This parameter is not tested but ensured by characterization. For endurance estimates in a specific
application, please consult the Total Endurance
™
Model which can be obtained from Microchip’s web site
at: www.microchip.com
21095K.book Page 3 Wednesday, December 5, 2012 2:28 PM