Document
PRELIMINARY
CG6257AM
4Mb (256K x 16) Pseudo Static RAM
Features
• Wide voltage range: 2.70V–3.30V • Access Time: 70ns • Ultra-low active power — Typical active current: 2.0mA @ f = 1 MHz • • • • — Typical active current: 13mA @ f = fmax Ultra low standby power Automatic power-down when deselected CMOS for optimum speed/power Offered in a 48 Ball BGA Package when deselected (CE HIGH or both BHE and BLE are HIGH). The input/output pins (I/O0 through I/O15) are placed in a high-impedance state when: deselected (CE HIGH ), outputs are disabled (OE HIGH), both Byte High Enable and Byte Low Enable are disabled (BHE, BLE HIGH), or during a write operation (CE LOW and WE LOW). The addresses must not be toggled once the read is started on the device. Writing to the device is accomplished by taking Chip Enables (CE LOW ) and Write Enable (WE) input LOW. If Byte Low Enable (BLE) is LOW, then data from I/O pins (I/O0 through I/O7), is written into the location specified on the address pins (A0 through A17). If Byte High Enable (BHE) is LOW, then data from I/O pins (I/O8 through I/O15) is written into the location specified on the address pins (A0 through A17). Reading from the device is accomplished by taking Chip Enables (CE LOW) and Output Enable (OE) LOW while forcing the Write Enable (WE) HIGH. If Byte Low Enable (BLE) is LOW, then data from the memory location specified by the address pins will appear on I/O0 to I/O7. If Byte High Enable (BHE) is LOW, then data from memory will appear on I/O8 to I/O15. See the truth table at the back of this datasheet for a complete description of read and write modes
Functional Description[1]
The CG6257AM is a high-performance CMOS Pseudo static RAM organized as 256K words by 16 bits that supports an asynchronous memory interface. This device features advanced circuit design to provide ultra-low active current. This is ideal for providing More Battery Life® (MoBL) in portable applications such as cellular telephones. The device can be put into standby mode reducing power consumption by more than 99% The device can also be put into standby mode
Logic Block Diagram
DATA IN DRIVERS A10 A9 A8 A7 A6 A5 A4 A3 A2 A1 A0 ROW DECODER
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256K × 16 RAM Array
SENSE AMPS
I/O0 – I/O7 I/O8 – I/O15
COLUMN DECODER
BHE WE OE BLE
A11 A12 A13 A14 A15 A16 A17
CE
Power- Down Circuit
BHE BLE
CE
Note: 1. For best-practice recommendations, please refer to the Cypress application note “System Design Guidelines” on http://www.cypress.com.
Weida Semiconductor, Inc. 38-XXXXX
Revised August 2003
PRELIMINARY
Pin Configuration[2, 3, 4]
FBGA
Top View 1 BLE I/O8 I/O9 VSS VCC I/O14 I/O15 NC/ A18 2 OE BHE I/O10 I/O11 3 A0 A3 A5 A17 4 A1 A4 A6 A7 A16 A15 A13 A10 5 A2 CE I/O1 I/O3 I/O4 I/O5 WE A11 6 NC I/O0 I/O2 Vcc Vss I/O6 I/O7 NC/ A20 A B C D E F G H
CG6257AM
I/O12 GND I/O13 NC/ A19 A8 A14 A12 A9
Note: 2. DNU pins have to be left floating. 3. Ball H1, G2 and ball H6 for the FBGA package can be used to upgrade to a 8M, 16M and a 32M density respectively. 4. NC “no connect” - not connected internally to the die.
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PRELIMINARY
Maximum Ratings
(Above which the useful life may be impaired. For user guidelines, not tested.) Storage Temperature ................................–65°C to + 150°C Ambient Temperature with Power Applied............................................ –55°C to + 125°C Supply Voltage to Ground Potential................. –0.4V to 4.6V
CG6257AM
DC Voltage Applied to Outputs in High Z State[5, 6, 7] ........................................–0.4V to 3.3V DC Input Voltage[5, 6, 7].....................................–0.4V to 3.3V Output Current into Outputs (LOW)............................. 20 mA Static Discharge Voltage .......................................... >2001V (per MIL-STD-883, Method 3015) Latch-Up Current .....................................................>200 mA
Operating Range[9]
Device CG6257AM Range Industrial Ambient Temperature –25°C to +85°C VCC 2.70V to 3.30V
Product Portfolio
Power Dissipation Product Min. CG6257AM 2.70 VCC Range (V) Typ.[8] 3.0 Max. 3.30 70 Speed (ns) Typ.[8] 2 Operating ICC(mA) f = 1MHz Max. 4 f = fmax Typ.[8] 13 Max. 17 Standby ISB2(µA) Typ.[8] 55 Max. 80
Notes: 5. VIL(MIN) = -0.5V for pulse durations less than 20ns. 6. VIH(Max) = Vcc + 0.5V for pulse durations less than 20ns. 7. Overshoot and undershoot specifications are characterized and are not 100% tested. 8. Typical values are included for reference only and are not guaranteed or tested. Typical values are measured at VCC = VCC(typ.), TA = 25°C. 9. Vcc must be at minimal operational levels before inputs are turned ON.
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PRELIMINARY
Electrical Characteristics Over the Operating Range
CG6257AM
CG6257AM-70 Parameter VCC VOH VOL VIH VIL IIX IOZ ICC Description Supplay Voltage Output HIGH Voltage IOH = –1.0 mA Output LOW Voltage IOL = 2.0mA Input HIGH Voltage Input LOW Volta.