Rad-Tolerant design of all-digital DLL Tuvia Liran ] Ran Ginosar ] Dov Alon ] Ramon-Chips Ltd., Israel Ramon Chips is named in memory of Col. Ilan Ramon, Israeli astronaut who died on board the Columbia space shuttle, 1/2/2003 Ramon Chips

2 Outline Issues with analog DLL/PLL All-digital DLL (ADDLL) architecture Radiation hardening of ADDLL Applications of ADDLL Integration of ADDLL in SOC Future developments

3 Issues with analog PLL Issues: - Sensitive to TID of analog - Might un-lock due to SET - Accumulate phase error due to SET - Might miss cycle due to SET - Sensitive to process, voltage, temperature

4 All-digital DLL concept Standard cell based logic  Operates at wide range of process, voltage & temperature Timing is controlled by logic Fast locking / immediate re-locking Low jitter – typically <1% of CLKREF period

DCDL operation 5 Gross tuning of delay Fine tuning of delay

DCDL response to control code 6

Radiation hardening of ADDLL Key radiation hazards: TID SEL Phase error due to SE Clock spike due to SET Reset/re-configure due to SEU/SET RH mitigation techniques The use of RadSafe TM std. cells – immunity to TID & SEL Use of SEP flip-flops mitigates SEU – immunity to change in control Glitch filtering at each DCDL stage – mitigates SET spikes Requirements for double sampling of reset – mitigates SET in reset/load 7

Advantages of ADDLL Voltage range – as logic core Temperature range – as logic core Lock time – limited # of cycles Re-locking time – immediate Standby power – zero Dynamic power – very low Bursts of clocks - enabled Control of slave delay lines - enabled Area – very small Floor planning – anywhere in the chip / I/O strip Immunity to Soft-Errors - Optional 8

ADDLL in RadSafe TM library 9

10 All-digital DLL cores Three DLL cores for 3 frequency ranges Locking guaranteed 0.05 mm 2 /core 8 Highly protected from radiation effects Can be placed anywhere in the core Powered by core supply lines

ADDLL application – de-skewing 11

ADDLL application – frequency multiplication 12

ADDLL application – master-slave operation 13

Other optional applications Frequency multiplication by 8X/16X … Frequency multiplication by non 2 n Duty cycle re-construction Digitally monitoring of aging/PVT Operation with bursts of clocks Frequency hoping 14

Record of integrating ADDLLs 15

16 Example of ADDLL (commercial IP) 80µ 140µ DCDL PHD Slave DCDL CTRL Slave CTRL SYNC Dig I/F TSMC/0.13u process MHz input clock Area: 0.01mm 2 Power: Located inside I/O ring DDR2 application

17 Summary ADDLL provides significant advantages over analog PLL/DLLs RH ADDLL overcomes the sensitivities of analog PLLs/DLLs ADDLL can be used for clock de-skewing and multiplication, and other applications RadSafe TM ADDLL is mature and proven