Texas Instruments BQ4013YMA-85, BQ4013YMA-70N, BQ4013YMA-70, BQ4013YMA-120, BQ4013MA-85 Datasheet

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Features

Data retention for at least 10 years without power

Automatic write-protection during power-up/power-down cycles

Conventional SRAM operation, including unlimited write cycles

Internal isolation of battery before power application

Industry standard 32-pin DIP pinout

bq4013/Y

128Kx8 Nonvolatile SRAM

General Description

The CMOS bq4013/Y is a nonvolatile 1,048,576-bit static RAM organized as

131,072 words by 8 bits. The integral control circuitry and lithium energy source provide reliable nonvolatility coupled with the unlimited write cycles of standard SRAM.

The control circuitry constantly monitors the single 5V supply for an out-of-tolerance condition. When VCC falls out of tolerance, the SRAM is unconditionally write-protected to prevent inadvertent write operation.

At this time the integral energy source is switched on to sustain the memory until after VCC returns valid.

The bq4013/Y uses an extremely low standby current CMOS SRAM, coupled with a small lithium coin cell to provide nonvolatility without long write-cycle times and the write-cycle limitations associated with EEPROM.

The bq4013/Y requires no external circuitry and is socket-compatible with industry-standard SRAMs and most EPROMs and EEPROMs.

Pin Connections	Pin Names
	A0–A16	Address inputs		Write enable input
			WE
	DQ0–DQ7	Data input/output	NC	No connect
		Chip enable input	VCC	Supply voltage input
	CE
		Output enable input	VSS	Ground
	OE

Selection Guide

	Maximum	Negative		Maximum	Negative
Part	Access	Supply	Part	Access	Supply
Number	Time (ns)	Tolerance	Number	Time (ns)	Tolerance
			bq4013YMA -70	70	-10%
bq4013MA -85	85	-5%	bq4013YMA -85	85	-10%
bq4013MA-120	120	-5%	bq4013YMA-120	120	-10%

9/96 D

bq4013/Y

Functional Description

When power is valid, the bq4013/Y operates as a standard CMOS SRAM. During power-down and power-up cycles, the bq4013/Y acts as a nonvolatile memory, automatically protecting and preserving the memory contents.

Power-down/power-up control circuitry constantly monitors the VCC supply for a power-fail-detect threshold VPFD. The bq4013 monitors for VPFD = 4.62V typical for use in systems with 5% supply tolerance. The bq4013Y monitors for VPFD = 4.37V typical for use in systems with 10% supply tolerance.

When VCC falls below the VPFD threshold, the SRAM automatically write-protects the data. All outputs become high impedance, and all inputs are treated as “don’t care.” If a valid access is in process at the time of power-fail detection, the memory cycle continues to completion. If the memory cycle fails to terminate within time tWPT, write-protection takes place.

As VCC falls past VPFD and approaches 3V, the control circuitry switches to the internal lithium backup supply, which provides data retention until valid VCC is applied.

When VCC returns to a level above the internal backup cell voltage, the supply is switched back to VCC. After VCC ramps above the VPFD threshold, write-protection continues for a time tCER (120ms maximum) to allow for processor stabilization. Normal memory operation may resume after this time.

The internal coin cell used by the bq4013/Y has an extremely long shelf life and provides data retention for more than 10 years in the absence of system power.

As shipped from Unitrode, the integral lithium cell of the MA-type module is electrically isolated from the memory. (Self-discharge in this condition is approximately 0.5% per year.) Following the first application of VCC, this isolation is broken, and the lithium backup cell provides data retention on subsequent power-downs.

Block Diagram

OE A0–A16

128K x 8

SRAM

WE Block DQ0–DQ7

Power CECON

CE Power-Fail VCC

Control

Lithium

Cell

BD-42

bq4013/Y

Truth Table


Mode	CE		WE	OE	I/O Operation	Power
Not selected		H	X	X	High Z	Standby
Output disable		L	H	H	High Z	Active
Read		L	H	L	DOUT	Active
Write		L	L	X	DIN	Active

Absolute Maximum Ratings

Symbol	Parameter	Value	Unit	Conditions
VCC	DC voltage applied on VCC relative to VSS	-0.3 to 7.0	V
VT	DC voltage applied on any pin excluding VCC	-0.3 to 7.0	V	VT ≤ VCC + 0.3
	relative to VSS
TOPR	Operating temperature	0 to +70	°C	Commercial
TOPR	Operating temperature	-40 to +85	°C	Industrial “N”
		-40 to +85	°C	Industrial “N”
TSTG	Storage temperature	-40 to +70	°C	Commercial
TSTG	Storage temperature	-40 to +85	°C	Industrial “N”
		-40 to +85	°C	Industrial “N”
TBIAS	Temperature under bias	-10 to +70	°C	Commercial
TBIAS	Temperature under bias	-40 to +85	°C	Industrial “N”
		-40 to +85	°C	Industrial “N”
TSOLDER	Soldering temperature	+260	°C	For 10 seconds

Note: Permanent device damage may occur if Absolute Maximum Ratings are exceeded. Functional operation should be limited to the Recommended DC Operating Conditions detailed in this data sheet. Exposure to conditions beyond the operational limits for extended periods of time may affect device reliability.

bq4013/Y

Recommended DC Operating Conditions (TA = TOPR)

Symbol	Parameter	Minimum	Typical	Maximum	Unit	Notes
VCC	Supply voltage	4.5	5.0	5.5	V	bq4013Y

		4.75	5.0	5.5	V	bq4013
		4.75	5.0	5.5	V	bq4013

VSS	Supply voltage	0	0	0	V
VIL	Input low voltage	-0.3	-	0.8	V
VIH	Input high voltage	2.2	-	VCC + 0.3	V
Note:	Typical values indicate operation at TA = 25°C.

DC Electrical Characteristics (TA = TOPR, VCCmin ≤ VCC ≤ VCCmax)

Symbol

Parameter

Minimum

Typical

Maximum

Unit

Conditions/Notes

ILI

Input leakage current

± 1

VIN = VSS to VCC

= VIH or

ILO

Output leakage current

± 1

WE = VIL

VOH

Output high voltage

2.4

IOH = -1.0 mA

VOL

Output low voltage

0.4

IOL = 2.1 mA

ISB1

Standby supply current

= VIH

≥ VCC - 0.2V,

ISB2

Standby supply current

2.5

0V ≤ VIN ≤ 0.2V,

or VIN ≥ VCC - 0.2V

ICC

Operating supply current

105

Min. cycle, duty = 100%,

CE = VIL, II/O = 0mA

VPFD

Power-fail-detect voltage

4.55

4.62

4.75

bq4013

4.30

4.37

4.50

bq4013Y

VSO

Supply switch-over voltage

Note:

Typical values indicate operation at TA = 25°C, VCC = 5V.

Capacitance (TA = 25°C, F = 1MHz, VCC = 5.0V)

Symbol

Parameter

Minimum

Typical

Maximum

Unit

Conditions

CI/O

Input/output capacitance

Output voltage = 0V

CIN

Input capacitance

Input voltage = 0V

Note:

These parameters are sampled and not 100% tested.

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