GAL20VP8 - Lattice Semiconductor

GAL20VP8
Discontinued Product (PCN #02-06). Contact Rochester Electronics for Availability.
www.latticesemi.com/sales/discontinueddevicessales.cfm
High-Speed E2CMOS PLD
Generic Array Logic™
Features
Functional Block Diagram
• HIGH DRIVE E2CMOS® GAL® DEVICE
— TTL Compatible 64 mA Output Drive
— 15 ns Maximum Propagation Delay
— Fmax = 80 MHz
— 10 ns Maximum from Clock Input to Data Output
— UltraMOS® Advanced CMOS Technology
I/CLK
I
I
IMUX
CLK
8
OLMC
I/O/Q
8
OLMC
I/O/Q
8
OLMC
I/O/Q
8
OLMC
I/O/Q
8
OLMC
I/O/Q
8
OLMC
I/O/Q
8
OLMC
I/O/Q
8
OLMC
I/O/Q
I
• ENHANCED INPUT AND OUTPUT FEATURES
— Schmitt Trigger Inputs
— Programmable Open-Drain or Totem-Pole Outputs
— Active Pull-Ups on All Inputs and I/O pins
PROGRAMMABLE
AND-ARRAY
(64 X 40)
I
2
• E CELL TECHNOLOGY
— Reconfigurable Logic
— Reprogrammable Cells
— 100% Tested/100% Yields
— High Speed Electrical Erasure (<100ms)
— 20 Year Data Retention
I
I
• EIGHT OUTPUT LOGIC MACROCELLS
— Maximum Flexibility for Complex Logic Designs
— Programmable Output Polarity
— Architecturally Compatible with Standard GAL20V8
I
I
• PRELOAD AND POWER-ON RESET OF ALL REGISTERS
— 100% Functional Testability
• APPLICATIONS INCLUDE:
— Ideal for Bus Control & Bus Arbitration Logic
— Bus Address Decode Logic
— Memory Address, Data and Control Circuits
— DMA Control
I
I
OE
I
I
IMUX
• ELECTRONIC SIGNATURE FOR IDENTIFICATION
I/OE
Description
Pin Configuration
The GAL20VP8, with 64 mA drive capability and 15 ns maximum
propagation delay time is ideal for Bus and Memory control applications.
The GAL20VP8 is manufactured using Lattice
Semiconductor's advanced E2CMOS process which combines
CMOS with Electrically Erasable (E2) floating gate technology. High
speed erase times (<100ms) allow the devices to be reprogrammed
quickly and efficiently.
PLCC
DIP
4
System bus and memory interfaces require control logic before
driving the bus or memory interface signals. The GAL20VP8
combines the familiar GAL20V8 architecture with bus drivers as
its outputs. The generic architecture provides maximum design flexibility by allowing the Output Logic Macrocell (OLMC) to be configured by the user. The 64mA output drive eliminates the need for
additional devices to provide bus-driving capability.
I
2
28
I/O/Q
I
I
I/CLK
NC
I
I
I/CLK
25
I
Vcc
I
I/O/Q
I
GAL
I/O/Q
I
20VP8
I/O/Q
GAL20VP8
23
I/O/Q
9
Top View
21
GND
I
I/O/Q
I
I/O/Q
I
I/O/Q
I
I/O/Q
NC
11
I
I/O/Q
I/O/Q
19
18
16
NC
I/OE
I
14
I
12
Unique test circuitry and reprogrammable cells allow complete AC,
DC, and functional testing during manufacture. As a result,
Lattice Semiconductor delivers 100% field programmability and
functionality of all GAL products. In addition, 100 erase/write cycles
and data retention in excess of 20 years are specified.
I
7
I
I
I/O/Q
I/O/Q
NC
I
24
I
26
5
1
I
I/O/Q
Vcc
I/O/Q
6
18
I
I/OE
GND
I/O/Q
12
13
I
Copyright © 1997 Lattice Semiconductor Corp. All brand or product names are trademarks or registered trademarks of their respective holders. The specifications and information herein are subject
to change without notice.
LATTICE SEMICONDUCTOR CORP., 5555 Northeast Moore Ct., Hillsboro, Oregon 97124, U.S.A.
Tel. (503) 268-8000; 1-800-LATTICE; FAX (503) 268-8556; http://www.latticesemi.com
20vp8_03
1
December 1997
Specifications GAL20VP8
Commercial Grade Specifications
Tpd (ns)
Tsu (ns)
Tco (ns)
Icc (mA)
15
8
10
115
GAL20VP8B-15LP
24-Pin Plastic DIP
115
GAL20VP8B-15LJ
28-Lead PLCC
115
GAL20VP8B-25LP
24-Pin Plastic DIP
115
GAL20VP8B-25LJ
28-Lead PLCC
25
10
15
Ordering #
Package
Part Number Description
XXXXXXXX
_
XX
X
X X
GAL20VP8B Device Name
Grade
Speed (ns)
L = Low Power
Power
Blank = Commercial
Package P = Plastic DIP
J = PLCC
2
Discontinued Product (PCN #02-06). Contact Rochester Electronics for Availability.
www.latticesemi.com/sales/discontinueddevicessales.cfm
GAL20VP8 Ordering Information
Specifications GAL20VP8
Discontinued Product (PCN #02-06). Contact Rochester Electronics for Availability.
www.latticesemi.com/sales/discontinueddevicessales.cfm
Output Logic Macrocell (OLMC)
The following discussion pertains to configuring the output logic
macrocell. It should be noted that actual implementation is accomplished by development software/hardware and is completely transparent to the user.
each macrocell controls the polarity of the output in any of the three
modes, while the AC1 and AC2 bit of each of the macrocells controls
the input/output and totem-pole/open-drain configuration. These
two global and 24 individual architecture bits define all possible configurations in a GAL20VP8. The information given on these architecture bits is only to give a better understanding of the device.
Compiler software will transparently set these architecture bits from
the pin definitions, so the user should not need to directly manipulate
these architecture bits.
There are three global OLMC configuration modes possible:
simple, complex, and registered. Details of each of these modes
is illustrated in the following pages. Two global bits, SYN and AC0,
control the mode configuration for all macrocells. The XOR bit of
Compiler Support for OLMC
Software compilers support the three different global OLMC modes
as different device types. Most compilers also have the ability to
automatically select the device type, generally based on the register
usage and output enable (OE) usage. Register usage on the device
forces the software to choose the registered mode. All combinatorial outputs with OE controlled by the product term will force the
software to choose the complex mode. The software will choose
the simple mode only when all outputs are dedicated combinatorial
without OE control. For further details, refer to the compiler software manuals.
In complex mode pin 1(2) and pin 12(14) become dedicated inputs and use the feedback paths of pin 22(26) and pin 14(17) respectively. Because of this feedback path usage, pin 22(26) and
pin 14(17) do not have the feedback option in this mode.
In simple mode all feedback paths of the output pins are routed
via the adjacent pins. In doing so, the two inner most pins (pins
17(20) and 19(23)) will not have the feedback option as these pins
are always configured as dedicated combinatorial output.
In addition to the architecture configurations, the logic compiler
software also supports configuration of either totem-pole or opendrain outputs. The actual architecture bit configuration, again, is
transparent to the user with the default configuration being the
standard totem-pole output.
When using compiler software to configure the device, the user
must pay special attention to the following restrictions in each mode.
In registered mode pin 1(2) and pin 12(14) are permanently configured as clock and output enable, respectively. These pins cannot
be configured as dedicated inputs in the registered mode.
3
Specifications GAL20VP8
Discontinued Product (PCN #02-06). Contact Rochester Electronics for Availability.
www.latticesemi.com/sales/discontinueddevicessales.cfm
Registered Mode
In the Registered mode, macrocells are configured as dedicated
registered outputs or as I/O functions.
Registered outputs have eight product terms per output. I/Os have
seven product terms per output.
All registered macrocells share common clock and output enable
control pins. Any macrocell can be configured as registered or I/
O. Up to eight registers or up to eight I/Os are possible in this mode.
Dedicated input or output functions can be implemented as subsets of the I/O function.
The JEDEC fuse numbers, including the User Electronic Signature
(UES) fuses and the Product Term Disable (PTD) fuses, are shown
on the logic diagram on the following page.
CLK
Registered Configuration for Registered Mode
D
XOR
- SYN=0.
- AC0=1.
- XOR=0 defines Active Low Output.
- XOR=1 defines Active High Output.
- AC1=0 defines this output configuration.
- AC2=1 defines totem pole output.
- AC2=0 defines open-drain output.
- Pin 1(2) controls common CLK for the registered
outputs.
- Pin 12(14) controls common OE for the registered
outputs.
- Pin 1(2) & Pin 12(14) are permanently configured as
CLK & OE for registered output configuration.
Q
Q
OE
Combinatorial Configuration for Registered Mode
- SYN=0.
- AC0=1.
- XOR=0 defines Active Low Output.
- XOR=1 defines Active High Output.
- AC1=1 defines this output configuration.
- AC2=1 defines totem pole output.
- AC2=0 defines open-drain output.
- Pin 1(2) & Pin 12(14) are permanently configured as
CLK & OE. for registered output configuration.
XOR
Note: The development software configures all of the architecture control bits and checks for proper pin usage automatically.
4
Specifications GAL20VP8
DIP (PLCC) Package Pinouts
1(2)
24(28)
0
4
8
12
16
20
24
28
32
36
PTD
2640
23(27)
OLMC
0000
22(26)
XOR-2560
AC1-2632
AC2-2706
0280
2(3)
OLMC
0320
21(25)
XOR-2561
AC1-2633
AC2-2707
0600
3(4)
OLMC
0640
20(24)
XOR-2562
AC1-2634
AC2-2708
0920
4(5)
OLMC
0960
19(23)
XOR-2563
AC1-2635
AC2-2709
1240
5(6)
OLMC
1280
17(20)
XOR-2564
AC1-2636
AC2-2710
1560
7(9)
OLMC
1600
16(19)
XOR-2565
AC1-2637
AC2-2711
1880
8(10)
OLMC
1920
15(18)
XOR-2566
AC1-2638
AC2-2712
2200
9(11)
OLMC
2240
14(17)
XOR-2567
AC1-2639
AC2-2713
2520
10(12)
13(16)
11(13)
OE
2703
64-USER ELECTRONIC SIGNATURE FUSES
2568, 2569, ....
.... 2630, 2631
Byte7 Byte6 ....
.... Byte1 Byte0
MSB
LSB
5
SYN-2704
AC0-2705
12(14)
Discontinued Product (PCN #02-06). Contact Rochester Electronics for Availability.
www.latticesemi.com/sales/discontinueddevicessales.cfm
Registered Mode Logic Diagram
Specifications GAL20VP8
In the Complex mode, macrocells are configured as output only or
I/O functions.
Discontinued Product (PCN #02-06). Contact Rochester Electronics for Availability.
www.latticesemi.com/sales/discontinueddevicessales.cfm
Complex Mode
All macrocells have seven product terms per output. One product
term is used for programmable output enable control. Pins 1(2) and
12(14) are always available as data inputs into the AND array.
Up to six I/Os are possible in this mode. Dedicated inputs or outputs
can be implemented as subsets of the I/O function. The two outer
most macrocells (pins 14(17) & 22(26)) do not have input capability.
Designs requiring eight I/Os can be implemented in the Registered
mode.
The JEDEC fuse numbers including the UES fuses and PTD fuses
are shown on the logic diagram on the following page.
Combinatorial I/O Configuration for Complex Mode
- SYN=1.
- AC0=1.
- XOR=0 defines Active Low Output.
- XOR=1 defines Active High Output.
- AC1 has no effect on this mode.
- AC2=1 defines totem pole output.
- AC2=0 defines open-drain output.
- Pin 15(18) through Pin 21(25) are configured to this
function.
XOR
Combinatorial Output Configuration for Complex Mode
- SYN=1.
- AC0=1.
- XOR=0 defines Active Low Output.
- XOR=1 defines Active High Output.
- AC1 has no effect on this mode.
- AC2=1 defines totem pole output.
- AC2=0 defines open-drain output.
- Pin 14(17) and Pin 22(26) are configured to this
function.
XOR
Note: The development software configures all of the architecture control bits and checks for proper pin usage automatically.
6
Specifications GAL20VP8
DIP (PLCC) Package Pinouts
1(2)
24(28)
0
4
8
12
16
20
24
28
32
36
PTD
2640
23(27)
0000
OLMC
XOR-2560
AC1-2632
AC2-2706
0280
2(3)
0320
22(26)
OLMC
XOR-2561
AC1-2633
AC2-2707
0600
3(4)
0640
21(25)
OLMC
XOR-2562
AC1-2634
AC2-2708
0920
4(5)
0960
20(24)
OLMC
XOR-2563
AC1-2635
AC2-2709
1240
5(6)
1280
19(23)
OLMC
XOR-2564
AC1-2636
AC2-2710
1560
7(9)
1600
17(20)
OLMC
XOR-2565
AC1-2637
AC2-2711
1880
8(10)
1920
16(19)
OLMC
XOR-2566
AC1-2638
AC2-2712
2200
9(11)
2240
15(18)
OLMC
XOR-2567
AC1-2639
AC2-2713
2520
10(12)
14(17)
13(16)
11(13)
12(14)
2703
64-USER ELECTRONIC SIGNATURE FUSES
2568, 2569, ....
.... 2630, 2631
Byte7 Byte6 ....
.... Byte1 Byte0
MSB
LSB
7
SYN-2704
AC0-2705
Discontinued Product (PCN #02-06). Contact Rochester Electronics for Availability.
www.latticesemi.com/sales/discontinueddevicessales.cfm
Complex Mode Logic Diagram
Specifications GAL20VP8
In the Simple mode, macrocells are configured as dedicated inputs
or as dedicated, always active, combinatorial outputs.
Discontinued Product (PCN #02-06). Contact Rochester Electronics for Availability.
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Simple Mode
Pins 1(2) and 12(14) are always available as data inputs into the
AND array. The center two macrocells (pins 17(20) & 19(23)) cannot be used in the input configuration.
All outputs in the simple mode have a maximum of eight product
terms that can control the logic. In addition, each output has programmable polarity.
The JEDEC fuse numbers including the UES fuses and PTD fuses
are shown on the logic diagram.
Combinatorial Output with Feedback Configuration
for Simple Mode
Vcc
- SYN=1.
- AC0=0.
- XOR=0 defines Active Low Output.
- XOR=1 defines Active High Output.
- AC1=0 defines this configuration.
- AC2=1 defines totem pole output.
- AC2=0 defines open-drain output.
- All OLMC except pins 17(20) & 19(23) can be
configured to this function.
XOR
Combinatorial Output Configuration for Simple Mode
Vcc
- SYN=1.
- AC0=0.
- XOR=0 defines Active Low Output.
- XOR=1 defines Active High Output.
- AC1=0 defines this configuration.
- AC2=1 defines totem pole output.
- AC2=0 defines open-drain output.
- Pins 17(20) & 19(23) are permanently configured to
this function.
XOR
Dedicated Input Configuration for Simple Mode
- SYN=1.
- AC0=0.
- XOR=0 defines Active Low Output.
- XOR=1 defines Active High Output.
- AC1=1 defines this configuration.
- AC2=1 defines totem pole output.
- AC2=0 defines open-drain output.
- All OLMC except pins 17(20) & 19(23) can be
configured to this function.
Note: The development software configures all of the architecture control bits and checks for proper pin usage automatically.
8
Specifications GAL20VP8
DIP (PLCC) Package Pinouts
1(2)
24(28)
0
4
8
12
16
20
24
28
32
36
PTD
2640
23(27)
0000
OLMC
XOR-2560
AC1-2632
AC2-2706
0280
2(3)
0320
22(26)
OLMC
XOR-2561
AC1-2633
AC2-2707
0600
3(4)
0640
21(25)
OLMC
XOR-2562
AC1-2634
AC2-2708
0920
4(5)
0960
20(24)
OLMC
XOR-2563
AC1-2635
AC2-2709
1240
5(6)
1280
19(23)
OLMC
XOR-2564
AC1-2636
AC2-2710
1560
7(9)
1600
17(20)
OLMC
XOR-2565
AC1-2637
AC2-2711
1880
8(10)
1920
16(19)
OLMC
XOR-2566
AC1-2638
AC2-2712
2200
9(11)
2240
15(18)
OLMC
XOR-2567
AC1-2639
AC2-2713
2520
10(12)
14(17)
13(16)
11(13)
12(14)
2703
64-USER ELECTRONIC SIGNATURE FUSES
2568, 2569, ....
.... 2630, 2631
Byte7 Byte6 ....
.... Byte1 Byte0
MSB
LSB
9
SYN-2704
AC0-2705
Discontinued Product (PCN #02-06). Contact Rochester Electronics for Availability.
www.latticesemi.com/sales/discontinueddevicessales.cfm
Simple Mode Logic Diagram
Specifications GAL20VP8
Recommended Operating Conditions
Supply voltage VCC ........................................ –.5 to +7V
Input voltage applied .......................... –2.5 to VCC +1.0V
Off-state output voltage applied ......... –2.5 to VCC +1.0V
Storage Temperature ................................ –65 to 150°C
Ambient Temperature with
Power Applied ........................................... –55 to 125°C
Commercial Devices:
Ambient Temperature (TA) ............................... 0 to 75°C
Supply voltage (VCC)
with Respect to Ground ..................... +4.75 to +5.25V
1. Stresses above those listed under the “Absolute Maximum
Ratings” may cause permanent damage to the device. These
are stress only ratings and functional operation of the device
at these or at any other conditions above those indicated in
the operational sections of this specification is not implied
(while programming, follow the programming specifications).
DC Electrical Characteristics
Over Recommended Operating Conditions (Unless Otherwise Specified)
SYMBOL
VIL
VIH
V I1
IIL2
IIH
VOL
VOH
IOL
IOH
IOS3
MIN.
TYP.4
MAX.
UNITS
Input Low Voltage
Vss – 0.5
—
0.8
V
Input High Voltage
2.0
—
Vcc+1
V
–1.2
V
PARAMETER
CONDITION
IIN = –32mA
Input Clamp Voltage
Vcc = Min.
Input or I/O Low Leakage Current
0V ≤ VIN ≤ VIL (MAX.)
—
—
–100
µA
Input or I/O High Leakage Current
3.5V ≤ VIN ≤ VCC
—
—
10
µA
Output Low Voltage
IOL = MAX. Vin = VIL or VIH
—
—
0.5
V
Output High Voltage
IOH = MAX. Vin = VIL or VIH
2.4
—
—
V
Low Level Output Current
—
—
64
mA
High Level Output Current
—
—
–32
mA
–60
—
–400
mA
—
90
115
mA
Output Short Circuit Current
COMMERCIAL
ICC
Operating Power
Supply Current
VCC = 5V VOUT = 0.5V
VIL = 0.5V VIH = 3.0V
—
TA = 25°C
L -15/-25
ftoggle = 15MHz Outputs Open
1) Characterized but not 100% tested.
2) The leakage current is due to the internal pull-up resistor on all pins. See Input Buffer section for more information.
3) One output at a time for a maximum duration of one second. Vout = 0.5V was selected to avoid test problems by tester ground
degradation. Characterized but not 100% tested.
4) Typical values are at Vcc = 5V and TA = 25 °C
10
Discontinued Product (PCN #02-06). Contact Rochester Electronics for Availability.
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Absolute Maximum Ratings(1)
Specifications GAL20VP8
Over Recommended Operating Conditions
PARAMETER
tpd
tco
tcf2
tsu
th
fmax3
twh
twl
ten
tdis
TEST
COND1.
COM
COM
-15
-25
MIN. MAX.
MIN. MAX.
DESCRIPTION
UNITS
A
Input or I/O to Combinational Output
3
15
3
25
ns
A
Clock to Output Delay
2
10
2
15
ns
—
Clock to Feedback Delay
—
4.5
—
10
ns
—
Setup Time, Input or Feedback before Clock ↑
8
—
10
—
ns
—
Hold Time, Input or Feedback after Clock ↑
0
—
0
—
ns
A
Maximum Clock Frequency with
External Feedback, 1/(tsu + tco)
55.5
—
40
—
MHz
A
Maximum Clock Frequency with
Internal Feedback, 1/(tsu + tcf)
80
—
50
—
MHz
A
Maximum Clock Frequency with
No Feedback
80
—
50
—
MHz
—
Clock Pulse Duration, High
6
—
10
—
ns
—
Clock Pulse Duration, Low
6
—
10
—
ns
B
Input or I/O to Output Enabled
—
15
—
20
ns
B
OE to Output Enabled
—
12
—
15
ns
C
Input or I/O to Output Disabled
—
15
—
20
ns
C
OE to Output Disabled
—
12
—
15
ns
1) Refer to Switching Test Conditions section.
2) Calculated from fmax with internal feedback. Refer to fmax Specification section.
3) Refer to fmax Specification section.
Capacitance (TA = 25°C, f = 1.0 MHz)
SYMBOL
PARAMETER
MAXIMUM*
UNITS
TEST CONDITIONS
CI
Input Capacitance
10
pF
VCC = 5.0V, VI = 2.0V
CI/O
I/O Capacitance
15
pF
VCC = 5.0V, VI/O = 2.0V
*Characterized but not 100% tested.
11
Discontinued Product (PCN #02-06). Contact Rochester Electronics for Availability.
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AC Switching Characteristics
Specifications GAL20VP8
INPUT or
I/O FEEDBACK
VALID INPUT
tsu
th
CLK
INPUT or
I/O FEEDBACK
VALID INPUT
tco
REGISTERED
OUTPUT
tpd
COMBINATIONAL
OUTPUT
1/fmax
(external fdbk)
Combinatorial Output
Registered Output
INPUT or
I/O FEEDBACK
OE
tdis
ten
tdis
COMBINATIONAL
OUTPUT
ten
REGISTERED
OUTPUT
Input or I/O to Output Enable/Disable
twh
OE to Output Enable/Disable
twl
CLK
1/ fmax (internal fdbk)
CLK
tcf
1/ fmax
(w/o fb)
REGISTERED
FEEDBACK
Clock Width
fmax with Feedback
12
tsu
Discontinued Product (PCN #02-06). Contact Rochester Electronics for Availability.
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Switching Waveforms
Specifications GAL20VP8
CLK
LOGIC
ARRAY
REGISTER
CLK
tsu
LOGIC
ARRAY
tco
REGISTER
fmax with External Feedback 1/(tsu+tco)
Note: fmax with external feedback is calculated from measured
tsu and tco.
t cf
t pd
CLK
fmax with Internal Feedback 1/(tsu+tcf)
LOGIC
ARRAY
Note: tcf is a calculated value, derived by subtracting tsu from
the period of fmax w/internal feedback (tcf = 1/fmax - tsu). The
value of tcf is used primarily when calculating the delay from
clocking a register to a combinatorial output (through registered
feedback), as shown above. For example, the timing from clock
to a combinatorial output is equal to tcf + tpd.
REGISTER
tsu + th
fmax with No Feedback
Note: fmax with no feedback may be less than 1/(twh + twl). This
is to allow for a clock duty cycle of other than 50%.
Switching Test Conditions
Input Pulse Levels
Input Rise and Fall Times
Input Timing Reference Levels
Output Timing Reference Levels
+5V
GND to 3.0V
3ns 10% – 90%
1.5V
1.5V
Output Load
R1
See Figure
3-state levels are measured 0.5V from steady-state active
level.
FROM OUTPUT (O/Q)
UNDER TEST
Output Load Conditions (see figure)
Test Condition
A
B
C
Active High
Active Low
Active High
Active Low
Discontinued Product (PCN #02-06). Contact Rochester Electronics for Availability.
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fmax Descriptions
TEST POINT
R2
R1
R2
CL
500Ω
∞
500Ω
∞
500Ω
500Ω
500Ω
500Ω
500Ω
500Ω
50pF
50pF
50pF
5pF
5pF
C L*
*C L INCLUDES TEST FIXTURE AND PROBE CAPACITANCE
13
Specifications GAL20VP8
Discontinued Product (PCN #02-06). Contact Rochester Electronics for Availability.
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operation, certain events occur that may throw the logic into an
illegal state (power-up, line voltage glitches, brown-outs, etc.). To
test a design for proper treatment of these conditions, a way must
be provided to break the feedback paths, and force any desired (i.e.,
illegal) state into the registers. Then the machine can be sequenced
and the outputs tested for correct next state conditions.
Electronic Signature
An electronic signature word is provided in every GAL20VP8 device. It contains 64 bits of reprogrammable memory that can contain
user defined data. Some uses include user ID codes, revision numbers, or inventory control. The signature data is always available
to the user independent of the state of the security cell.
The GAL20VP8 device includes circuitry that allows each registered
output to be synchronously set either high or low. Thus, any present
state condition can be forced for test sequencing. If necessary,
approved GAL programmers capable of executing test vectors can
perform output register preload automatically.
NOTE: The electronic signature is included in checksum calculations. Changing the electronic signature will alter the checksum.
Signature Cell
Input Buffers
The security cell is provided on all GAL20VP8 devices to prevent
unauthorized copying of the array patterns. Once programmed,
the circuitry enabling array is disabled, preventing further programming or verification of the array. The cell can only be erased by reprogramming the device, so the original configuration can never
be examined once this cell is programmed. Signature data is always available to the user.
The GAL20VP8 devices are designed with TTL level compatible
input buffers. These buffers have a characteristically high impedance, and present a much lighter load to the driving logic than
bipolar TTL devices.
GAL20VP8 input buffers have active pull-ups within their input
structure. As a result, unused inputs and I/O's will float to a TTL
"high" (logical "1"). Lattice Semiconductor recommends that all unused inputs and tri-stated I/O pins for both devices be connected
to another active input, VCC, or GND. Doing this will tend to improve
noise immunity and reduce ICC for the device.
Latch-Up Protection
GAL20VP8 devices are designed with an on-board charge pump
to negatively bias the substrate. The negative bias is of sufficient
magnitude to prevent input undershoots from causing the circuitry
to latch. Additionally, outputs are designed with n-channel pull-ups
instead of the traditional p-channel pull-ups to eliminate any possibility of SCR induced latching.
Typical Input Pull-up Characteristic
Bulk Erase Mode
Input Current (µA)
0
During a programming cycle, a clear function performs a bulk erase
of the array and the architecture word. In addition, the electronic
signature word and the security cell are erased. This mode resets
a previously configured device back to its original state, which is
all JEDEC ones.
-20
-40
-60
0
Schmitt Trigger Inputs
1.0
2.0
3.0
4.0
Input Voltage (Volts)
One of the enhancements of the GAL20VP8 for bus interface logic
implementation is input gysteresis. The threshold of the positive
going edge is 1.5V, while the threshold of the negative going edge
is 1.3V. This provides a typical hysteresis of 200mV between
positive and negative transitions of the inputs.
Programmable Open-Drain Outputs
5.0
In addition to the standard GAL20V8 type configuration, the outputs of the GAL20VP8 are individually programmable either as a
standard totempole output or an open-drain output. The totempole
output drives the specified VOH and VOL levels whereas the opendrain output drives only the specified VOL. The VOH level on the
open-drain output depends on the external loading and pull-up. This
output configuration is controlled by the AC2 fuse. When AC2 cell
is erased (JEDEC "1") the output is configured as a totempole output and when AC2 cell is programmed (JEDEC "0") the output is
configured as an open-drain. The default configuration when the
device is in bulk erased state is totempole configuration. The AC2
fuses associated with each of the outputs is included in all of the
logic diagrams.
Bulk Erase Mode
All eight outputs of the GAL20VP8 are capable of driving 64 mA
loads when driving low and 32 mA loads when driving high. Near
symmetrical high and low output drive capability provides small
skews between high-to-low and low-to-high output transitions.
Output Register Preload
When testing state machine designs, all possible states and state
transitions must be verified in the design, not just those required
in the normal machine operations. This is because, in system
14
Specifications GAL20VP8
Vcc
Vcc (min.)
t su
t wl
CLK
t pr
INTERNAL REGISTER
Q - OUTPUT
Internal Register
Reset to Logic "0"
FEEDBACK/EXTERNAL
OUTPUT REGISTER
Device Pin
Reset to Logic "1"
Circuitry within the GAL20VP8 provides a reset signal to all registers during power-up. All internal registers will have their Q outputs set low after a specified time (tpr, 1µs MAX). As a result, the
state on the registered output pins (if they are enabled) will always
be high on power-up, regardless of the programmed polarity of
the output pins. This feature can greatly simplify state machine
design by providing a known state on power-up. The timing diagram for power-up is shown above. Because of the asynchro-
nous nature of system power-up, some conditions must be met
to provide a valid power-up reset of the GAL20VP8. First, the VCC
rise must be monotonic. Second, the clock input must be at static
TTL level as shown in the diagram during power up. The registers
will reset within a maximum of tpr time. As in normal system operation, avoid clocking the device until all input and feedback path
setup times have been met. The clock must also meet the minimum pulse width requirements.
Input/Output Equivalent Schematics
PIN
PIN
Feedback
Vcc
Active Pull-up
Circuit
Active Pull-up
Circuit
Vcc
Vref
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Power-Up Reset
Tri-State
Control
Vcc
ESD
Protection
Circuit
Vcc
Vref
Data
Output
PIN
PIN
ESD
Protection
Circuit
Feedback
(To Input Buffer)
Vref = 3.1V
Vref = 3.1V
Typical Input
Typical Output
15
Specifications GAL20VP8
Normalized Tpd vs Vcc
1.2
1.2
1.1
PT L->H
1
0.9
0.8
RISE
1.1
Normalized Tsu
PT H->L
Normalized Tco
FALL
1
0.9
4.75
5.00
5.25
5.50
4.50
4.75
Supply Voltage (V)
Normalized Tpd vs Temp
5.00
5.25
PT L->H
1.1
1
0.9
0.8
4.50
0
25
50
75
100
RISE
1.1
FALL
1
0.9
0.8
1.3
PT H->L
1.2
PT L->H
1.1
1
0.9
0.8
0.7
-25
0
25
50
75
100
125
-55
-25
Temperature (deg. C)
0
0
-0.1
-0.2
-0.3
RISE
-0.4
FALL
-0.5
-0.25
-0.5
-0.75
RISE
-1
FALL
-1.25
3
4
5
6
7
8
1
Number of Outputs Switching
2
3
4
5
6
7
8
Number of Outputs Switching
Delta Tpd vs Output Loading
Delta Tco vs Output Loading
6
6
4
RISE
Delta Tco (ns)
RISE
FALL
2
0
4
FALL
2
0
-2
-2
0
50
100
150
200
250
0
300
50
100
150
200
250
Output Loading (pF)
Output Loading (pF)
16
25
50
75
100
Temperature (deg. C)
Delta Tco vs # of Outputs
Switching
0
2
5.50
1.4
1.2
Delta Tpd vs # of Outputs
Switching
1
5.25
Normalized Tsu vs Temp
-55
125
5.00
Normalized Tco vs Temp
Temperature (deg. C)
Delta Tpd (ns)
-25
Delta Tpd (ns)
-55
4.75
Supply Voltage (V)
0.7
0.7
0.9
Supply Voltage (V)
Normalized Tsu
Normalized Tco
PT H->L
1.2
PT L->H
1
5.50
1.3
1.3
PT H->L
1.1
0.8
0.8
4.50
Delta Tco (ns)
Normalized Tpd
1.2
Normalized Tpd
Normalized Tsu vs Vcc
Normalized Tco vs Vcc
300
125
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Typical AC and DC Characteristic Diagrams
Specifications GAL20VP8
Voh vs Ioh
5
0.4
4
0.3
0.2
0.1
4.25
3
2
20.00
40.00
60.00
80.00
3.5
0.00
10.00
20.00
30.00
40.00
50.00
60.00
0.00
1.00
2.00
3.00
Iol (mA)
Ioh(mA)
Ioh(mA)
Normalized Icc vs Vcc
Normalized Icc vs Temp
Normalized Icc vs Freq.
1.10
1.00
0.90
0.80
1.2
1.40
1.1
1.30
Normalized Icc
Normalized Icc
1.20
1
0.9
0.8
0.7
4.50
4
3.75
0
0.00
Normalized Icc
4.5
1
0
4.75
5.00
5.25
-25
0
25
75
100
125
Temperature (deg. C)
0
10
2.5
20
Iik (mA)
2
1.5
1
30
40
50
60
0.5
70
0
80
0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00
Vin (V)
1.20
1.10
1.00
-2.00
-1.50
-1.00
Vik (V)
17
-0.50
0
25
50
75
Frequency (MHz)
Input Clamp (Vik)
Delta Icc vs Vin (1 input)
3
4.00
0.90
-55
5.50
Supply Voltage (V)
Delta Icc (mA)
Voh vs Ioh
Voh (V)
0.5
Voh (V)
Vol (V)
Vol vs Iol
0.00
100
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Typical AC and DC Characteristic Diagrams
Notes
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18