Datasheet
2007 Microchip Technology Inc. DS21161H-page 3
24LCS21A
TABLE 1-2: AC CHARACTERISTICS
Parameter Symbol
Vcc = 2.5-4.5V
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 THIGH 4000 — 600 — ns
Clock low time TLOW 4700 — 1300 — ns
SDA and SCL rise time T
R — 1000 — 300 ns (Note 1)
SDA and SCL fall time TF — 300 — 300 ns (Note 1)
Start condition hold time THD: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 TSU:STO 4000 — 600 — ns
Output valid from clock TAA — 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 VIH
minimum to V
IL maximum
T
OF — 250 20 + 0.1
C
B
250 ns (Note 1), CB 100 pF
Input filter spike suppression
(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 VCLK T
VAA — 2000 — 1000 ns
VCLK high time TVHIGH 4000 — 600 — ns
VCLK low time T
VLOW 4700 — 1300 — ns
VCLK setup time TVHST 0—0—ns
VCLK hold time TSPVL 4000 — 600 — ns
Mode transition time T
VHZ — 1000 — 500 ns
Transmit-only power-up time TVPU 0—0—ns
Input filter spike suppression
(VCLK pin)
TSPV — 100 — 100 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 Schmitt Trigger inputs which provide 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.