M35080

2/18

Figure 2. DIP and SO Connections

Note: 1. NC = Not Connected.

1

AI02144B

2

3

4

8

7

6

5

NC

VSS

C

D

Q

S

VCC

W

M35080

Note: 1. Except for the rating “Operating Temperature Range”, stresses above those listed in the Table “Absolute Maximum Ratings” may

cause permanent damage to the device. These are stress ratings only and operation of the device at these or any other

conditions above those indicated in the Operating sections of this specification is not implied. Exposure to Absolute Maximum

Rating conditions for extended periods may affect device reliability. Refer also to the ST SURE Program and

other relevant quality documents.

2. MIL-STD-883C, 3015.7 (100pF, 1500W).

3. EIAJ IC-121 (Condition C) (200pF, 0W).

Symbol

Parameter

Value

Unit

Ambient Operating Temperature

-40 to 125

°C

Storage Temperature

-65 to 150

°C

Lead Temperature during Soldering

PSDIP8: 10 sec

SO8: 40 sec

260

215

°C

Output Voltage Range

V

Input Voltage Range

-0.3 to 6.5

V

Supply Voltage Range

-0.3 to 6.5

V

4000

V

400

V

The memory is organized in pages of 32 bytes.

However, the first page is not treated in the same

way as the others. Instead, it is considered to con-

sist of sixteen 16-bit incremental registers. Each

register can be modified using the conventional

write instructions, but the new value will only be

accepted if it is greater than the current value.

Thus, each register is restricted to being modified

monotonically upwards.

This is useful in applications where it is necessary

to implement a counter that is protected from

fraudulent tampering (such as in a car odometer,

an electricity meter, or a tally for remaining credit).

SIGNAL DESCRIPTION

Serial Output (Q)

The output pin is used to transfer data serially out

of the Memory. Data is shifted out on the falling

edge of the serial clock.

Serial Input (D)

The input pin is used to transfer data serially into

the device. Instructions, addresses, and the data

to be written, are each received this way. Input is

latched on the rising edge of the serial clock.

Serial Clock (C)

The serial clock provides the timing for the serial

interface (as shown in Figure 3). Instructions, ad-

dresses, or data are latched, from the input pin, on

the rising edge of the clock input. The output data

on the Q pin changes state after the falling edge of

the clock input.

Chip Select (S)

When S is high, the memory device is deselected,

and the Q output pin is held in its high impedance

state. Unless an internal write operation is under-

way, the memory device is placed in its stand-by

power mode.

After power-on, a high-to-low transition on S is re-

quired prior to the start of any operation.

Write Protect (W)

The protection features of the memory device are

summarized in Table 3.

The hardware write protection, controlled by the W

pin, restricts write access to the Status Register