ST M48Z512A, M48Z512AY User Manual

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4 Mbit (512Kb x8) ZEROPOWERSRAM

■ INTEGRATED LOW POWER SRAM,

POWER-FAIL CONTROL CIRCUIT and
BATTERY

■ CONVENTIONAL SRAM OPERATION;

UNLIMITED WRITE CYCLES

■ 10 YEARS of DATA RETENTION in the

ABSENCE of POWER

■ AUTOMATIC POWER-FAIL CHIP DESELECT

and WRITE PROTECTION

■ WRITE PROTECT VOLTAGES

(V

= Power-fail Deselect Voltage):

PFD

– M48Z512A: 4.50V ≤ V
– M48Z512AY: 4.20V ≤ V

■ BATTERY INTERNALLY ISOLATED UNTIL

POWER IS APPLIED

■ PIN and FUNCTION COMPATIBLE with

JEDEC STANDARD 512K x 8 SRAMs

■ SURFACE MOUNT CHIP SET PACKAGING

INCLUDES a 28-PIN SOIC and a 32-LEAD
TSOP (SNAPHAT TOP TO BE ORDERED
SEPARATELY)

■ SOIC PACKAGE PROVIDES DIRECT

CONNECTION for a SNAPHAT TOP WHICH
CONTAINS the BATTERY

■ SNAPHAT



HOUSING (BATTERY) IS

REPLACEABLE

PFD

PFD

≤ 4.75V

≤ 4.50V

32

1

PMDIP32 (PM)

Module

32

1

TSOP II 32

(10 x 20mm)

Surface Mount Chip Set Solution (CS)

Figure 1. Logic Diagram

V

CC

M48Z512A

M48Z512AY

SNAPHAT (SH)

Battery

SOH28

Table 1. Signal Names

A0-A18 Address Inputs

DQ0-DQ7 Data Inputs / Outputs

E Chip Enable

G Output Enable

W Write Enable
V

CC

V

SS

Supply Voltage

Ground

A0-A18

W

19

M48Z512A

M48Z512AY

E

G

V

SS

8

DQ0-DQ7

AI02043

1/17March 2000

M48Z512A, M48Z512AY

Table 2. Absolute Maximum Ratings

Symbol Parameter Value Unit

T

A

T

STG

T

BIAS

(2)

T

SLD

V

IO

V

CC

Note: 1. Stresses greater thanthose listed under ”Absolute MaximumRatings” maycause permanent damage to the device. This is astress

rating only and functional operation of the device at these or any other conditions above those indicated in the operational section
of this specification is not implied. Exposure to the absolute maximum rating conditions for extended periods of time may affect
reliability.

2. Soldering temperature not to exceed 260°C for 10 seconds (total thermal budget not to exceed 150°C for longer than 30 seconds).

CAUTION: Negative undershoots below –0.3V are not allowed on any pin while in the Battery Back-up mode.

Ambient Operating Temperature 0 to 70 °C
Storage Temperature (VCCOff) –40 to 70 °C
Temperature Under Bias –40 to 70 °C

Lead Solder Temperature for 10 seconds 260 °C
Input or Output Voltages –0.3 to 7 V

Supply Voltage –0.3 to 7 V

(1)

Table 3. Operating Modes

Mode

Deselect
Write V
Read
Read V

V

CC

4.75V to 5.5V
or

4.5V to 5.5V

E G W DQ0-DQ7 Power

V

IH

IL

V

IL

IL

X X High Z Standby
XVILD

V

IL

V

IH

V

IH

V

IH

IN

D

OUT

High Z Active

Active
Active

Deselect
Deselect ≤ V

Note: 1. X = VIHor VIL;VSO= Battery Back-up Switchover Voltage.

to V

V

SO

PFD

SO

(min)

X X X High Z CMOS Standby
X X X High Z Battery Back-up Mode

Figure 2. DIP Connections

A18 V
A16
A14
A12

A7
A6
A5
A4
A3
A2
A1
A0

DQ0

DQ2

SS

1
2

4
5
6
7

M48Z512A

8

M48Z512AY

9
10
11
12
13
14
15
16

32
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17

AI02044

CC

A15
A173
W
A13
A8
A9
A11
G
A10
E
DQ7
DQ6
DQ5DQ1
DQ4
DQ3V

DESCRIPTION

The M48Z512A/512AY ZEROPOWERRAM is a
non-volatile 4,194,304 bit Static RAM organized
as 524,288 words by 8 bits. The device combines
an internal lithium battery, a CMOS SRAM and a
control circuit in a plastic 32 pin DIP Module.

For surface mount environments ST provides a
Chip Set solution consisting of a 28 pin 330mil
SOIC NVRAM Supervisor (M40Z300) and a 32 pin
TSOP Type II (10 x 20mm) LPSRAM (M68Z512)
packages.

The unique design allows the SNAPHAT battery
package to be mounted on top of the SOIC pack­age after the completion of the surface mount pro­cess. Insertion of the SNAPHAT housing after
reflow prevents potential battery damage due to
the high temperatures required for device surface­mounting. The SNAPHAT housing is keyed topre­vent reverse insertion.

The SNAPHAT battery package is shipped sepa­rately in plastic anti-static tubes or in Tape & Reel
form. The part number is ”M4Zxx-BR00SH1”.

2/17

Figure 3. Block Diagram

M48Z512A, M48Z512AY

V

CC

A0-A18

POWER

VOLTAGE SENSE

E

AND

SWITCHING

CIRCUITRY

INTERNAL
BATTERY

The M48Z512A/512AY also has itsown Power-fail
Detect circuit.The controlcircuitry constantlymon­itors the single 5V supply for an out of tolerance
condition. When VCCis out oftolerance, the circuit
write protects the SRAM, providing a high degree
of data security in the midst of unpredictable sys­tem operation brought on by low VCC.AsVCCfalls
below approximately 3V, the control circuitry con­nects the battery which maintains data until valid
power returns.

The ZEROPOWER RAM replaces industry stan­dard SRAMs. It provides the nonvolatility of
PROMs without any requirement for special write

512K x

SRAM ARRAY

E

8

V

SS

DQ0-DQ7

W

G

AI02045

timing or limitations on the number of writes that
can be performed.

The M48Z512A/512AY has its own Power-fail De­tect Circuit. The control circuitry constantly moni­tors the single 5V supply for an out of tolerance
condition. When VCCis out of tolerance, the circuit
write protects the SRAM, providing a high degree
of data security in the midst of unpredictable sys­tem operations brought on by low VCC.AsV
falls below approximately 3V, the control circuitry
connectsthe battery whichsustains data untilvalid
power returns.

CC

3/17

M48Z512A, M48Z512AY

Figure 4. Hardware Hookup for SMT Chip Set

(2)

M40Z300

E1
E2
E3
E4

V

SS

V

CON
CON
CON
CON

OUT

RST

BL

SNAPHAT
BATTERY

THS

(3)

E

A

B

(1)

V

CC

E2

M68Z512

E

A0-A18

W

DQ0-DQ7

V

SS

AI03631

Note: 1. For pin connections, see individual data sheets for M40Z300 and M68Z512 at www.st.com.

2. Connect THS pin to V

3. SNAPHAT top ordered separately.

Table 4. AC Measurement Conditions

OUT

if 4.2V ≤ V

≤ 4.5V (M48Z512AY) or connect THS pin to VSSif 4.5V ≤ V

PFD

Figure 5. AC Testing Load Circuit

Input Rise and Fall Times ≤ 5ns
Input Pulse Voltages 0 to 3V
Input and Output Timing Ref. Voltages 1.5V

Note that Output Hi-Z is defined as the point where dataisno longer
driven.

DEVICE
UNDER

TEST

1kΩ

CLincludes JIG capacitance

≤ 4.75V (M48Z512A).

PFD

5V

1.9kΩ

CL= 100pF or

OUT

5pF

AI01030

4/17

M48Z512A, M48Z512AY

Table 5. Capacitance

(1, 2)

(TA=25°C, f = 1MHz)

Symbol Parameter Test Condition Min Max Unit

C

IN

C

IO

Note: 1. Effective capacitance measured with power supply at 5V.

2. Sampled only, not 100% tested.

3. Outputs deselected.

Input Capacitance

(3)

Input / Output Capacitance

V

V

OUT

IN

=0V

=0V

10 pF
10 pF

Table 6. DC Characteristics

(TA= 0 to 70 °C; VCC= 4.75V to 5.5V or 4.5V to 5.5V)

Symbol Parameter Test Condition Min Max Unit

(1)

I

LI

I

LO

I

CC

I

CC1

I

CC2

V

IL

V

IH

V

OL

V

OH

Note: 1. Outputs deselected.

Input Leakage Current

(1)

Output Leakage Current
Supply Current E = VIL, Outputs open 115 mA
Supply Current (Standby) TTL

Supply Current (Standby) CMOS
Input Low Voltage –0.3 0.8 V
Input High Voltage 2.2 VCC+ 0.3 V
Output Low Voltage

Output High Voltage IOH= –1mA 2.4 V

0V ≤ V

0V ≤ V

E ≥ V

I

OL

IN

OUT

E=V

– 0.2V

CC

= 2.1mA

≤ V

≤ V

IH

CC

CC

±1 µA
±1 µA

10 mA

5mA

0.4 V

Table 7. Power Down/Up TripPoints DC Characteristics

(1)

(TA= 0 to 70 °C)

Symbol Parameter Min Typ Max Unit

V

PFD

V

SO

t

DR

Note: 1. All voltages referenced to VSS.

2. At 25 °C.

Power-fail Deselect Voltage

Battery Back-up Switchover Voltage 3 V

(2)

Data Retention Time 10 YEARS

M48Z512A 4.5 4.6 4.75 V
M48Z512AY 4.2 4.3 4.5 V

5/17

M48Z512A, M48Z512AY

Table 8. Power Down/Up AC Characteristics

(TA= 0 to 70 °C)

Symbol Parameter Min Max Unit

(1)

t

F

t

FB

t

WP

t

R

V

(max) to V

(2)

PFD

V

(min) to VSOVCCFallTime

PFD

PFD

Write Protect Time from VCC=V
VSOto V

(max) VCCRise Time

PFD

(min) VCCFall Time

PFD

300 µs

10 µs
40 150 µs

0 µs

t

ER

Note: 1. V

2. V

E Recovery Time 40 120 ms

(max) to V

PFD

(min).

es V

PFD

(min) to VSOfall time of less than tFBmay cause corruption of RAM data.

PFD

(min) fall time of less than tFmay result indeselection/write protection not occurring until 200µs after VCCpass-

PFD

Figure 6. Power Down/Up Mode AC Waveforms

V

CC

V

(max)

PFD

V

(min)

PFD

V

SO

tF

tFB

tWP

E

OUTPUTS

VALID VALID

(PER CONTROL INPUT)

tDR

DON’T CARE

HIGH-Z

tR

tER

RECOGNIZEDRECOGNIZED

(PER CONTROL INPUT)

6/17

AI01031