FM22LD16-55-BGTR - Ramtron

Pre-Production

This is a product in the pre-production phase of development. Device Ramtron International Corporation

characterization is complete and Ramtron does not expect to change the 1850 Ramtron Drive, Colorado Springs, CO 80921

specifications. Ramtron will issue a Product Change Notice if any (800) 545-FRAM, (719) 481-7000

specification changes are made. http://www.ramtron.com

Rev. 2.0

Dec. 2009 Page 1 of 14

FM22LD16

4Mbit F-RAM Memory

Features

4Mbit Ferroelectric Nonvolatile RAM

• Organized as 256Kx16

• Configurable as 512Kx8 Using /UB, /LB

• 10

Read/Write Cycles

• NoDelay™ Writes

• Page Mode Operation to 40MHz

• Advanced High-Reliability Ferroelectric Pro cess

SRAM Compatible

• JEDEC 256Kx16 SRAM Pinout

• 55 ns Access Time, 110 ns Cycle Time

Advanced Features

• Software Programmable Block Write Protect

Superior to B a ttery-backed SRAM Modules

• No Battery Concerns

• Monolithic Reliability

• True Surface Mount Solution, No Rework Steps

• Superior for Moisture, Shock, and Vibration

Low Power Operation

• 2.7V – 3.6V Power Supply

• Low Standby Current (90µA typ.)

• Low Active Current (8 mA typ.)

Industry Sta ndard Configuratio n

• Industrial Temperature -40° C to +85° C

• 48-ball “Green”/RoHS FBGA package

• Pin compatible with FM21LD16 (2Mb) and

FM23MLD16 (8Mb)

Description

The FM22LD16 is a 256Kx16 nonvolatile memory

that reads and writes like a standard SRAM. A

ferroelectric random access memory or F-RAM is

nonvolatile, which means that data is retained after

power is removed. It provides data retention for over

10 years while eliminating the reliability concerns,

functional disadvantages, and system design

complexities of battery-backed SRAM (BBSRAM).

Fast write timing and high write endurance make the

F-RAM superior to other types of memory.

In-system operatio n of the FM2 2LD16 is very similar

to other RAM devices and can be used as a drop-in

replacement for standard SRAM. Read and write

cycles may be triggered by /CE or simply by

changing the address. The F-RAM memory is

nonvolatile due to its unique ferroelectric memory

process. These features make the FM22LD16 ideal

for nonvolatile memory applications requiring

frequent or rapid writes in the form of an SRAM.

The FM22LD16 includes a low voltage monitor that

blocks access to the memory array when V

drops

below V

min. The memory is protected against an

inadvertent access and data corruption under this

condition. The device also features software-

controlled write protection. The memory array is

divided into 8 uniform blocks, each of which can be

individually write protected.

The device is available in a 48-ball FBGA package.

Device specifications are guaranteed over industrial

temperature range –40°C to +85°C.

Pin Configuration

/LB /OE A0 A1 A2 NC

DQ8 /UB A3 A4 /CE DQ0

DQ9 DQ10 A5 A6 DQ1 DQ2

VSS DQ11 A17 A7 DQ3 VDD

VDD DQ12 NC A16 DQ4 VSS

DQ14 DQ13 A14 A15 DQ5 DQ6

DQ15 NC A12 A13 /WE DQ7

NC A8 A9 A10 A11 NC

123456

Top View (Ball Down)

Ordering Information

FM22LD16-55-BG 55 ns access, 48-ball

“Green”/RoHS FBGA

FM22LD16-55-BGTR 55 ns access, 48-ball

“Green”/RoHS FBGA,

Tape & Reel

FM22LD16 - 256Kx16 FRAM

Rev. 2.0

Dec. 2009 Page 2 of 14

Figure 1. Block Diagram

Pin Description

Pin Name Type Pin Description

A(17:0) Input Address inputs: The 18 address lines select one of 262,144 words in the F-RAM array. The

lowest two address lines A(1:0) may be used for page mode read and write operations.

/CE Input Chip Enable input: The device is selected and a new memory access begins when /CE is

low. The entire address is latched in ternally on the falling edge of /CE. Subsequent changes

to the A(1:0) address inputs allow page mode operation when /CE is low.

/WE Input Write Enable: A write cycle begins when /WE is asserted. The rising edge causes the

FM22LD16 to write the data on the DQ bus to the F-RAM array. The falling edge of /WE

latches a new column address for page mode write cycles.

/OE Input Output Enable: When /OE is low, the FM22LD16 drives the data bus when valid read data is

available. Deasserting /OE high tri-states the DQ pins .

DQ(15:0) I/O Data: 16-bit bi-directional data bus for accessing the F-RAM array.

/UB Input Upper Byte Select: Enables DQ(15:8) pins during reads and writes. Deasserting /UB high

tri-states the DQ pins. If the user does not perform byte writes and the device is not

configured as a 512Kx8, the /UB and /LB pins may be tied to ground.

/LB Input Lower Byte Select: Enables DQ(7:0) pins during reads and writes. Deasserting /LB high tri-

states the DQ pins. If the user does not perform byte writes and the device is not configured

as a 512Kx8, the /UB and /LB pins may be tied to ground.

VDD Supply Supply Voltage

VSS Supply Ground

FM22LD16 - 256Kx16 FRAM

Rev. 2.0

Dec. 2009 Page 3 of 14

Functional Trut h Table

1,2

/CE /WE A(17:2) A(1:0) Operation

H X X X Standby/Idle

↓ H V V Read

L H No Change Change Page Mode Read

L H Change V Random Read

↓ L V V /CE-Controlled Write

L ↓ V V /WE-Controlled Write

L ↓ No Change V Page Mode W rite

↑ X X X Starts Precharge

Notes:

1) H=Logic High , L=Logic Low, V = Vali d Data, X=Don’t Care.

2) /WE-cont rolled write cycle begins as a Read cycle and A(17:2 ) i s latched then.

3) Addresses A(1:0) must remain stable for at least 10 ns during page mode operation.

4) For write cycles, data-in is latched on the rising edge of /CE or /WE, whichever comes first.

Byte Select Trut h Table

/OE /LB /UB Operation

H X X Read; Outputs Disabled

X H H

L H L Read; DQ(7:0) Hi-Z

L H Read; DQ(15:8) Hi-Z

L L Read

X H L Write; Mask DQ(7:0)

L H Write; Mask DQ(15:8)

L L Write

The /UB and /LB pins may be grounded if 1) the system does not

perform byte writes and 2) the device is not configured as a 512Kx8.

FM22LD16 - 256Kx16 FRAM

Rev. 2.0

Dec. 2009 Page 4 of 14

Overview

The FM22LD16 is a wordwide F-RAM memory

logically organized as 262,144 x 16 and accessed

using an industry standard parallel interface. All data

written to the part is immediately nonvolatile with no

delay. The device offers page mode operation which

provides higher speed access to addresses within a

page (row). An access to a different page requires that

either /CE transitions low or the upper address

A(17:2) changes.

Memory Operation

Users access 262,144 memory locations, each with 16

data bits through a parallel interface. The F-RAM

array is organized as 8 blocks each having 8192 rows.

Each row has 4 column locations, which allows fast

access in page mode operation. Once an initial

address has been latched by the falling edge of /CE,

subsequent column locations may be accessed

without the need to toggle /CE. When /CE is

deasse rted high, a pr echarge oper ation begins. Writes

occur immediately at the end of the access with no

delay. The /WE pin must be toggled for each write

operation. The write data is stored in the nonvolatile

memory array immediately, which is a feature unique

to F-RAM called NoDelay

writes.

Read Operation

A read operation begins on the falling edge of /CE.

The falling edge of /CE causes the address to be

latched and starts a memory read cycle if /WE is high.

Data becomes available on the bus after the access

time has been satisfied. Once the address has been

latched and the access completed, a new access to a

random location (different r ow) may begin while /CE

is still low. The minimum cycle time for random

addresses is t

. Note that unlike SRAMs, the

FM22LD16’s /CE-initiated access time is faster than

the address cycle time.

The FM22LD16 will drive the data bus when /OE

and at least one of the byte enables (/UB, /LB) is

asserted low. The upp er data byte is driven when /UB

is low, and the lower data byte is driven when /LB is

low. If /OE is asserted after the memory access time

has been satisfied, the data bus will be driven with

valid data. If /OE is asserted prior to completion of

the memory access, the data bus will not be driven

until valid data is available. This feature minimizes

supply current in the system by eliminating transients

caused by invalid data being driven onto the bus.

When /OE is deasserted high, the data bus will

remain in a high-Z state.

Write Operation

Writes occur in the FM22LD16 in the same time

interval as reads. The FM22LD16 supports both /CE-

and /WE-controlled write cycles. In both cases, the

address A(17:2) is latched on the falling edge of /CE.

In a /CE-controlled write, the /WE signal is asserted

prior to beginning the memory cycle. That is, /WE is

low when /CE falls. In this case, the device begins the

memory cycle as a write. The FM22LD16 will not

drive the data bus regardless of the state of /OE as

long as /WE is low. Input data must be valid when

/CE is d easserted high. I n a /WE-controlled write, the

memory cycle begins on the falling edge of /CE. The

/WE signal falls some time later. Therefore, the

memory cycle begins as a read. The data bus will be

driven if /OE is low, however it will hi-Z once /WE is

asserted low. The /CE- and /WE-controlled write

timing cases are shown in the Electrical

Specifications section.

Write access to the array begins on the falling edge of

/WE after the memory cycle is initiated. The write

access terminates on the rising edge of /WE or /CE,

whichever comes first. A valid write operation

requires the user to meet the access time specification

prior to deasserting /WE or /CE. Data setup time

indicates the interval during which data cannot

change prior to the end of the write access (rising

edge of /WE or /CE).

Unlike other truly nonvolatile memory technologies,

there is no write delay with F-RAM. Since the read

and write access times of the underlying memory are

the same, the user experiences no delay through the

bus. The entire memory operation occurs in a single

bus cycle. Data polling, a technique used with

EEPROMs to determine if a write is complete, is

unnecessa ry.

Page Mode Operation

The F-RAM array is organized as 8 blocks each

having 8192 rows. Each row has 4 column address

locations. Address inputs A(1:0) define the column

address to be accessed. An access can start on any

column address, and other column locations may be

accessed without the need to toggle the /CE pin. For

fast access reads, once the first data byte is driven

onto the bus, the column address inputs A(1:0) may

be changed to a new value. A new data byte is then

driven to the DQ p ins no later than t

AAP

, which is less

than half the initial read access time. For fast access

writes, the first write pulse defines the first write

access. While /CE is low, a subsequent write pulse

FM22LD16 - 256Kx16 FRAM

Rev. 2.0

Dec. 2009 Page 5 of 14

along with a new column address provides a page

mode write access.

Precharge Operation

The precharge operation is an internal condition in

which the state of the memory is being prepared for a

new access. Precharge is user-initiated by driving the

/CE signal high. It must remain high for at least the

minimum precharge time t

Precharge is also activated by changing the upper

addess A(17:2). The current row is first closed prior

to accessing the new row. The device automatically

detects an upper order address change which starts a

precharge operation, the new address is latched, and

the new read data is valid within the t

address

access time. Refer to the Read Cycle Timing 1

diagram on page 10. Likewise a similar sequence

occurs for write cycles. Refer to the Write Cycle

Timing 3 diagram on page 12. The rate at which

random addresses can be issued is t

and t

respectively.

Software Write Protection

The 256Kx16 address space is divided into 8 sectors

(blocks) of 32Kx16 each. Each sector can be

individually software write-protected and the settings

are nonvolatile. A unique address and command

sequence invokes the write protection mode.

To modify write protection, the system host must

issue six read commands, three write commands, and

a final read command. The specific sequence of read

addresses must be provided in order to access to the

write protect mode. Following the read address

sequence, the host must write a data byte that

specifies the desired protection state of each sector.

For confirmation, the system must then write the

complement of the protection byte immediately

following the protection byte. Any error that occurs

including r ead a ddr esses in the wrong o rd er, issuing a

seventh read address, or failing to complement the

protection value will leave the write protection

unchanged.

The write protect state machine monitors all

addresses, taking no action until this particular

read/write sequence occurs. During the address

sequence, each read will occur as a valid operation

and data from the corresponding addresses will be

driven onto the data bus. Any address that occurs out

of sequence will cause the software protection state

machine to start over. After the address sequence is

completed, the next operation must be a write cycle.

The d ata byte contains the write-protect settings. T his

value will not be written to the memory array, so the

address is a d on’t-care. Rather it will be held pending

the next cycle, which must be a write of the data

complement to the protection settings. If the

complement is correct, the write protect settings will

be adjusted. If not, the process is aborted and the

address sequence starts over. The data value written

after the correct six add resses will not be entered into

memory.

The protection data byte consists of 8-bits, each

associated with the write protect state of a sector. The

data byte must be driven to the lower 8-bits of the

data bus, DQ(7:0). Setting a bit to 1 write protects the

corresponding sector; a 0 enables writes for that

sector. The following table shows the write-protect

sectors with the corresponding bit that controls the

write-protect setting.

Write Protect Sectors – 32K x16 blocks

Sector 7 3FFFFh – 38000h

Sector 6 37FFFh – 30000h

Sector 5 2FFFFh – 28000h

Sector 4 27FFFh – 20000h

Sector 3 1FFFFh – 18000h

Sector 2 17FFFh – 10000h

Sector 1 0FFFFh – 08000h

Sector 0 07FFFh – 00000h

The write-protect read address sequence follows:

1. 24555h *

2. 3AAAAh

3. 02333h

4. 1CCCCh

5. 000FFh

6. 3EF00h

7. 3AAAAh

8. 1CCCCh

9. 0FF00h

10. 00000h

* If /CE is low entering the sequence, then an

address of 00000h must precede 24555h.

The address sequence provides a very secure way of

modifying the protection. The write-protect sequence

has a 1 in 3 x 10

chance of randomly accessing

exactly the 1

six addresses. The odds are further

reduced by requiring three more write cycles, one that

requires an exact inversion of the data byte. A flow

chart of the entire write protect op eration is shown in

Figure 2. The write-protect settings are nonvolatile.

The factory default: all blocks are unp r otected.

FM22LD16 - 256Kx16 FRAM

Rev. 2.0

Dec. 2009 Page 6 of 14

Figure 2. Write-Protect State Machine

For example, the following sequence write-protects addresses from 18000h to 27FFFh (sectors 3 & 4):

Address Data

Read 24555h -

Read 3AAAAh -

Read 02333h -

Read 1CCCCh -

Read 000FFh -

Read 3EF00h -

Write 3AAAAh 18h ; bits 3 & 4 = 1

Write 1CCCCh E7h ; complement of 18h

Write 0FF00h - ; Data is don’t care

Read 00000h - ; return to Normal Operation

FM22LD16 - 256Kx16 FRAM

Rev. 2.0

Dec. 2009 Page 7 of 14

Software Write Protect Timing

SRAM Drop-In Replacement

The FM22LD16 has been designed to be a drop-in

replacement for standard asynchronous SRAMs. The

device does not require /CE to toggle for each new

address. /CE may remain low indefinitely. While /CE

is low, the device automatically detects address

changes and a new access is begun. This functionality

allows /CE to be grounded as you might with an

SRAM. It also allows page mode operation at speeds

up to 40MHz. Note that if /CE is tied to ground,

the user must be sure /WE is not low at powerup

or powerdown events. If /CE and /WE are both

low during power cycles, data corruption will

occur. Figure 3 shows a pullup resistor on /WE

which will keep the pin high during power cycles

assuming the MCU/MPU pin tri-states during the

reset condition. The pullup resistor value should

be chosen to ensure the /WE pin tracks V

yet a

high enough value that the current drawn when

/WE is low is not an issue. A 10Kohm resistor

draws 330uA when /WE is low and V

=3.3V.

Figure 3. Use of Pullup Resistor on /WE

NOTE: If /CE is tied to ground, the user gives up

the ability to perform the software write-protect

sequence.

For applications that require the lowest power

consumption, the /CE signal should be active only

during memory accesses. The FM22LD16 draws

supply current while /CE is low, even if addresses and

control signals are static. While /CE is high, the

device draws no more than the maximum standby

current I

The FM22LD16 is backward compatible with the

1Mbit FM20L08 and 256Kbit FM18L08 devices.

That is, operating the FM22LD16 with /CE toggling

low on every address is perfectly acceptable.

The /UB and /LB byte select pins are active for both

read and write cycles. They may be used to allow the

device to be wired as a 512Kx8 memory. The upper

and lower data bytes can be tied together and

controlled with the byte selects. Individual byte

enables or the next higher address line A(18) may be

available from the system processor.

Figure 4. FM22LD16 Wired as 512Kx8

A(17:0)

FM22LD16

MCU/

MPU

FM22LD16 - 256Kx16 FRAM

Rev. 2.0

Dec. 2009 Page 8 of 14

Electrical Specifications

A bsolute Maximum R atings

Symbol Description Ratings

Power Supply Voltage with respect to V

-1.0V to +4.5V

Voltage on any signal pin with respect to V

-1.0V to +4.5V and

< V

+1V

STG

Storage Temperature -55°C to +125°C

LEAD

Lead Temperature (Soldering, 10 seconds) 260° C

ESD

Electrostatic Discharge Voltage

- Human Body Model (JEDEC Std JESD22-A114-D)

- Charged Device Model (JEDEC Std JESD22-C101-C)

- Machine Model (JEDEC Std JESD22-A115-A)

2.5kV

1.5kV

150V

Package Moisture Sensitivity Level MSL-3

Stresses above those listed under Absolute Maximum Ratings may cause permanent damage to the device. This is a stress rating

only, and the functional operation of the device at these or any other conditions above those listed in the operational section of this

specification is not implied. Exposure to absolute maximum ratings conditions for extended periods may affect device reliability.

DC Operating Conditions (T

= -40° C to + 85 ° C, V

= 2.7V to 3.6V unless otherwise specified)

Symbol Parameter Min Typ Max Units Notes

Power Supply 2.7 3.3 3.6 V

Power Supply Current 8 12 mA 1

Standby Current

@ T

= 25°C

@ T

= 85°C

150

270

µA

Input Leakage Current ±1 µA 3

Output Leakage Current ±1 µA 3

Input High Voltage 2.2 V

+ 0.3 V

Input Low Voltage -0.3 0.6 V

OH1

Output High Voltage (

= -1.0 mA)

2.4 V

OH2

Output High Voltage (

= -100 µA)

-0.2 V

OL1

Output Low Voltage (

= 2.1 mA)

0.4 V

OL2

Output Low Voltage (

= 100 µA)

0.2 V

Notes

= 3.6V, /CE cycling at min. cycle time. All inputs toggling at CMOS levels (0.2V or V

-0.2V), all DQ pins unloaded.

= 3.6V, /CE at V

, All other pins are static and at CMOS levels (0.2V or V

-0.2V).

, V

OUT

between V

and V

FM22LD16 - 256Kx16 FRAM

Rev. 2.0

Dec. 2009 Page 9 of 14

Read Cycle AC Parameters (T

= -40° C to + 85 ° C, V

= 2.7V to 3.6V unless otherwise specified)

Symbol Parameter Min Max Units Notes

Read Cycle Time 110 - ns

Chip Enable Access Time - 55 ns

Address Access Time - 110 ns

Output Hold Time 20 - ns

AAP

Page Mode Address Access Time - 25 ns

OHP

Page Mode Output Hold Time 5 - ns

Chip Enable Active Time 55 - ns

Precharge Time 55 - ns

/UB, /LB Access Time - 20 ns

Address Setup Time (to /CE low) 0 - ns

Address Hold Time (/CE-controlled) 55 - ns

Output Enable Access Time - 15 ns

Chip Enable to Output High-Z - 10 ns 1

OHZ

Outp ut Enable High to Output High-Z - 10 ns 1

BHZ

/UB, /LB High to Output High-Z - 10 ns 1

Write Cycle AC Parameters (T

= -40° C to + 85 ° C, V

= 2.7V to 3.6V unless otherwise specified)

Symbol Parameter Min Max Units Notes

Write Cycle Time 110 - ns

Chip Enable Active Time 55 - ns

Chip Enable to Write Enable High 55 - ns

Precharge Time 55 - ns

PWC

Page Mode Write Enable Cycle Time 25 - ns

Write Enable Pulse Width 16 - ns

Address Setup Time (to /CE low) 0 - ns

ASP

Page Mode Address Setup Time (to /WE low) 8 - ns

AHP

Page Mode Address Hold Time (to /WE low) 15 - ns

WLC

Write Enable Low to /CE High 25 - ns

BLC

/UB, /LB Low to /CE High 25 - ns

Write Enable Low to A(17:2) Change 25 - ns

AWH

A(17:2) Change to Write Enable High 110 - ns

/UB, /LB Setup Time (to /CE low) 2 - ns

/UB, /LB Hold Time (to /CE high) 0 - ns

Data Input Setup Time 14 - ns

Data Input Hold Time 0 - ns

Write Enable Low to Output High Z - 10 ns 1

Write Enable High to Output Dr iven 10 - ns 1

Write Enab le to /CE Low Setup Time 0 - ns 2

Write Enable to /CE High Hold Time 0 - ns 2

Notes

1 This parameter is characterized but not 100% tested.

2 The relationship between /CE and /WE determines if a /CE- or /WE-controlled write occurs. The parameters t

and t

are not t est ed.

Capacitance (T

= 25° C , f=1 MHz, V

= 3.3V)

Symbol Parameter Min Max Units Notes

I/O

Input/Output Capacitance (DQ) - 8 pF

Input Capacitance - 6 pF

FM22LD16 - 256Kx16 FRAM

Rev. 2.0

Dec. 2009 Page 10 of 14

Power Cycle Timing (T

= -40° C to + 85 ° C, V

= 2.7V to 3.6V unless otherwise specified)

Symbol Parameter Min Max Units Notes

Power-Up (after V

min. is reached) to First Access Time 450 - µs

Last Write (/WE high) to Power Down Time 0 - µs

Rise Time 50 - µs/V 1,2

Fall Time 100 - µs/V 1,2

Notes

1 Slope measured at any point on V

waveform.

2 Ramtron cannot test or characterize all V

power ramp profiles. The behavior of the internal circuits is difficult to predict

whe n V

is below the level of a transistor threshold voltage. Ramtron strongly recommends that V

power up faster than

100ms through the range of 0.4V to 1.0V.

Data Retention (V

= 2.7V to 3.6V)

Parameter Min Units Notes

Data Retention 10 Years

AC Test Conditions

Input Pulse Levels 0 to 3V Input and Output Timing Levels 1.5V

Input Rise and Fall Times 3 ns Output Load Capacitance 30pF

Read Cycle Timing 1 (/CE low, /OE low)

Read Cycle Timing 2 (/CE-controlled)

A(17:0)

DQ(15:0)

tAS

tHZ

tOE

tOH

tOHZ

UB / LB

tBA tBHZ

tCA tPC

tAH

tCE

FM22LD16 - 256Kx16 FRAM

Rev. 2.0

Dec. 2009 Page 11 of 14

Page Mode Read Cycle Timing

Although seque ntia l column addressing is sho wn, it is not r e quired.

Write Cycle Timing 1 (/WE-Controlled)

Note: /OE (not shown) is low only to show effect of /WE on DQ pins

Write Cycle Timing 2 (/CE-Controlled)

A(17:0)

DQ(15:0)

tWS

tAS

tWH

tDH

tDS

D in

tCA tPC

UB/LB

tBLC

FM22LD16 - 256Kx16 FRAM

Rev. 2.0

Dec. 2009 Page 12 of 14

Write Cycle Timing 3 (/CE low)

Note: /OE (not shown) is low only to show effect of /WE on DQ pins

Page Mode Write Cycle Timing

Although seque ntia l column addressing is sho wn, it is not r e quired.

Power Cycle Timing

FM22LD16 - 256Kx16 FRAM

Rev. 2.0

Dec. 2009 Page 13 of 14

Mechanical Drawing

48-ba ll F BGA (0.75mm ball pitch)

Note: All dimensions in millimeters.

48 FBGA Package Marking Scheme

Legend:

XXXXXX= part number, S=speed, P=package

LLLLLL= lot code, YY=year, WW=work week

Examples: FM22LD16, “Green”/RoHS FBGA package,

Lot C8556953BG1, Year 2008, Work Week 44

RAMTRON

FM22LD16-55-BG

C8556953BG1

0844

RAMTRON

XXXXXXX-S-P

LLLLLLL

YYWW

FM22LD16 - 256Kx16 FRAM

Rev. 2.0

Dec. 2009 Page 14 of 14

Revision History

Revision

Date

Summary

1.0 10/2/2008 Initial release.

1.1 2/18/2009 Added UB/LB signals to timing diagrams and added timing parameters to AC

table. Added tape & reel ordering information.

2.0 12/22/2009 Changed status to Pre-Production. Lowered I

limit. Added UB/LB signals

to timing diagrams and added timing parameters to AC table. Expand ed

explanation of precharge operation. Updated lead temperature rating in Abs

Max table. Removed V

spec. Added tape & reel ordering information.