Differences between CY62147G and CY62146G Asynchronous Memory Parts – KBA219723
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Translation - Japanese: 非同期メモリ部品のCY62147GとCY62146Gの違いについて – KBA219723 - Community Translated (JA)
Question:
What are the differences between CY62147G/CY62147E/CY62157E /CY62167E and CY62146G/ CY62136F/ CY62146E Asynchronous SRAMs?
Answer:
The devices differ from each other in terms of Byte-power down feature. For MPNs CY62XX7X, disabling BHE#/BLE# at the same time deselects the device and places it in standby mode. The device consumes ISB2 current. For MPNS CY62XX6X, disabling BHE#/BLE# has the same effect as disabling OE#. It only disables the I/Os but the device is still selected. This difference in byte-power down feature affects the duration taken by device to provide data output on BHE#/BLE# assertion (tDBE).
The tDBE (BLE#/BHE# LOW to data valid) parameter is different for both devices. For a comparison of the tDBE parameter, see the table below:
Parameter | Description | MPN | Period |
tDBE | BLE / BHE LOW to data valid | CY62147G CY62147E CY62157E CY62167E CY62167EV | 45ns 45ns 45ns 45ns 45ns |
tDBE | BLE / BHE LOW to data valid | CY62146G CY62136F CY62146E
| 22ns 22ns 22ns |
See the figure below for the tDBE parameter.
Figure 1. Read Cycle (OE# Controlled)
See the device datasheets for more details timing parameters.
The two series of MPNs also differ in terms of truth table. In CY62147G/CY62147E/CY62157E/CY62167E, if BHE# and BLE# are high then the part is deselected or powered down. Whereas in CY62146G/CY62136F/CY62146E, only the I/Os are disabled provided the WE# is high and the chip is selected. So, the CY62146G/CY62136F/CY62146E part will consume more current than the other parts which will only consume standby current for this combination of BHE# and BLE#. See the datasheet for more details.
Truth Table – CY62146G/CY62146GE/CY62146GSL/CY62146GESL
CE1# | CE2 | WE# | OE# | BHE# | BLE# | Inputs/Outputs | Mode | Power |
H | X] | X | X | X | X | HI-Z | Deselect/Power-down | Standby (ISB) |
X | L | X | X | X | X | HI-Z | Deselect/Power-down | Standby (ISB) |
L | H | H | L | L | L | Data Out (I/O0–I/O15) | Read | Active (ICC) |
L | H | H | L | H | L | Data Out (I/O0–I/O7); | Read | Active (ICC) |
L | H | H | L | L | H | HI-Z (I/O0–I/O7); | Read | Active (ICC) |
L | H | H | H | X | X | HI-Z | Output disabled | Active (ICC) |
L | H | H | X | H | H | HI-Z | Output disabled | Active (ICC) |
L | H | L | X | L | L | Data In (I/O0–I/O15) | Write | Active (ICC) |
L | H | L | X | H | L | Data In (I/O0–I/O7); | Write | Active (ICC) |
L | H | L | X | L | H | HI-Z (I/O0–I/O7); | Write | Active (ICC) |
Truth Table – CY62147G/CY62147GE
CE1# | CE2 | WE# | OE# | BHE# | BLE# | Inputs/Outputs | Mode | Power |
H | X | X | X | X | X | HI-Z | Deselect/Power-down | Standby (ISB) |
X | L | X | X | X | X | HI-Z | Deselect/Power-down | Standby (ISB) |
X | X | X | X | H | H | HI-Z | Deselect/Power-down | Standby (ISB) |
L | H | H | L | L | L | Data Out (I/O0–I/O15) | Read | Active (ICC) |
L | H | H | L | H | L | Data Out (I/O0–I/O7); | Read | Active (ICC) |
L | H | H | L | L | H | HI-Z (I/O0–I/O7); | Read | Active (ICC) |
L | H | H | H | L | H | HI-Z | Output disabled | Active (ICC) |
L | H | H | H | H | L | HI-Z | Output disabled | Active (ICC) |
L | H | H | H | L | L | HI-Z | Output disabled | Active (ICC) |
L | H | L | X | L | L | Data In (I/O0–I/O15) | Write | Active (ICC) |
L | H | L | X | H | L | Data In (I/O0–I/O7); | Write | Active (ICC) |
L | H | L | X | L | H | HI-Z (I/O0–I/O7); | Write | Active (ICC) |
Note: The ‘X’ (Don’t care) state for the chip enables refers to the logic state (either HIGH or LOW). Intermediate voltage levels on these pins are not permitted.
- Tags:
- 4-mbit
- asynchronous
- bhe
- ble
- bus width
- cy62136f
- cy62146e
- cy62146g
- cy62146ge
- cy62146gesl
- cy62146gsl
- cy621472g
- cy62147e
- cy62147g
- cy62147ge
- cy62157e
- cy62167d
- cy62167e
- data valid
- datasheet
- deselected
- difference
- ecc
- memory
- micropower
- powered down
- standby current
- static ram
- tdbe