BETA-MULTIPLIER REFERENCE GENERATOR

BANDGAP REFERENCE GENERATOR

GROUP3 – DEBASHIS BANERJEE JASON PINTO

ASHITA MATHEW

ECE4430 Project Presentation

DESIGN SPECIFICATIONS

Technology Node – TSMC 0.18µm

Required Design Specifications

Supply voltage 1.2 V

Vref 0.7 V

Iref 15µA

Max Supply Sensitivity

1000ppm

Max Temp Sensitivity 10ppm @37 º C

Max Power consumption

20uW

BMR -TOPOLOGY USED

BMR- DESIGN CALCULATIONS

Using these we get:

Sweeping to set current, we get

BMR- ACHIEVED SPECIFICATIONS

Parameter Values

1 Supply (V) 1.2 V

2 Supply Sensitivity (ppm)

611.9

3Temp Sensitivity (ppm @ 37˚C)

1e06 ppm(Iref),.99e06 ppm(Vref)

4 Iref (uA) 15.15

5 Iref with ΔVTHn = 10% 0.02µA

6ΔIref with ΔVTHp = 10%

1.818nA

7 ΔIref with ΔR= 10% 3.585µA

8Minimum Supply Voltage(mV)

646.4

9Maximum Supply Voltage(V)

1.7

Parameter Values

10 TCIref (ppm/˚C) 3323

11 TCVref (ppm/˚C) 3202

12 Power Consumption (µW) 50.23

13 Resistor Value (KΩ) 5.67KΩ

Iref- VDD Sweep

Startup transient responseStartup time:460.6nsec

Vref- VDD Sweep

Vref= 0.718V

Current sensitivity with supply voltage = 611.9ppm @37˚C

Voltage sensitivity with supply voltage= 9333ppm @37˚C

PSRR of Vref

PSRR of Iref

PSRR of Vref = 40dB

PSRR of Iref = 125e6 mho

Iref changes by 1.818nA for +-10% variation in Vthp

Iref changes by 0.02uA for +-10% variation in Vthn

TCIref of 3323 ppm/ ˚C at 37 ˚C

TCVref of 3202ppm/ ˚C @ 37˚C

BGR TOPOLOGY USED

DIFFERENTIAL AMP STRUCTURE

BGR DESIGN CALCULATIONS

With the above values of L,N,R we observed that the ICTAT and IPTAT fail to cancel out exactly at 37 deg C. So through simulations we have adjusted R,L,N to obtain the desired characteristics.The values obtained areL = 8.5, N=4.84, R= 9.84K

ACHIEVED SPECIFICATIONS

Parameter Specs obtained

1 Supply (V) 1.2 V

2 Vref (V) 0.698V

3 Supply Sensitivity (ppm) 5213ppm

4 Temp Sensitivity (ppm @ 37C) 0.39ppm

5 Power consumption (uW) 63uW

6 Iref (uA) 14.69uA

7 ΔIref with ΔVTHn = 10% 124.8nA

8 Δ Iref with ΔVTHp = 10% 1.925nA

9 ΔIref with ΔR= 10% 3.1uA

10 Minumum Supply Voltage 901mV

11 Maximum Supply Voltage 2.786V

12 TCIref 0.13ppm/deg C

13 TCVref (ppm) 1.258e-3 ppm/deg C

14 PSRR for Vref 53.2dB

15 PSRR for Iref 2.18e+7 mho

Vref – Voltage Sweep Iref – Voltage Sweep

Vref- Temp Sweep Iref- Temp Sweep

Vref =0.697VIref =14.61uA

700.9mV @ 37.03C 14.69uA @ 37.01C

Vdd min =901mV

Vdd max =2.786VVdd min =904mV

Vdd max =2.788V

TCVref TCIref

Voltage Sensitivity - Vref Voltage Sensitivity - Iref

Temp sensitivity = 0.39ppm Temp sensitivity =4.15ppm

Volt sensitivity = 5213ppm Volt sensitivity = 5229ppm

PSRR for Vref PSRR for Iref

PSRR = 53.2dB

PSRR = 2.18*107 mho

Start up delay

Start up delay = 189ns

Power consumption

Power consumption= 63uW

Δ IREF WITH VTH VARIATION

Δ IREF for 10% variation in Vthn = 124.8nA

Δ IREF for 10% variation in Vthp = 1.925nA

DEVIATION FROM SPECS

Parameter Specs BMR Specs Obtained

BMR Specs Error

BGR Specs obtained

BGR Specs Error

1 Vref (V) 0.7 0.718V 2.65% 0.698V 0.28%

2Supply

Sensitivity (ppm)

1000 611.9 (Iref) -38.81% 5213 (Vref) 421.3%

3Temp

Sensitivity (ppm @ 37C)

10 1e06 (Iref).99e6 (Vref) - 4.1(Iref)

0.39(Vref) -

4 Iref (uA) 15 15.15 1% 14.69 -2.06%

5Power

consumption (uW)

20 50.23 151.15% 63 215%

CONCLUSIONTemperature sensitivity was observed to be better in

a BGR than compared to a BMR because there is PTAT and CTAT cancellation.

Voltage sensitivity is much better in BMR than in BGR.Supply sensitivity is better with stacked devices , but

since the supply voltage is small, we cannot use cascode topology.

Both BMR and BGR are supposed to work at low frequency. So we used a min value of L = 4*0.18um. This led to a high output impedance and hence lesser voltage sensitivity.

Careful design of a high gain differential amplifier would lead to a much better voltage sensitivity.

Questions??

Thank you…