MC34166TH - Motorola / Freescale Semiconductor

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Order this document by MC34166/D

SEMICONDUCTOR

TECHNICAL DATA

POWER SWITCHING

REGULATORS

T SUFFIX

PLASTIC PACKAGE

CASE 314D

ORDERING INFORMATION

Device Operating

Temperature Range Package

Pin 1. Voltage Feedback Input

2. Switch Output

3. Ground

4. Input Voltage/VCC

5. Compensation/Standby

TH SUFFIX

PLASTIC PACKAGE

CASE 314A

TV SUFFIX

PLASTIC PACKAGE

CASE 314B

Heatsink surface connected to Pin 3.

D2T SUFFIX

PLASTIC PACKAGE

CASE 936A

(D2PAK)

Heatsink surface (shown as terminal 6

in case outline drawing) is connected to Pin 3.

MC33166D2T

MC33166T

MC33166TH

MC33166TV

TA = – 40° to + 85°C

Surface Mount

Straight Lead

Horiz. Mount

Vertical Mount

MC34166D2T

MC34166T

MC34166TH

MC34166TV

TA = 0

to + 70

Surface Mount

Straight Lead

Horiz. Mount

Vertical Mount

MOTOROLA ANALOG IC DEVICE DATA

  

The MC34166, MC33166 series are high performance fixed frequency

power switching regulators that contain the primary functions required for

dc–to–dc converters. This series was specifically designed to be

incorporated in step–down and voltage–inverting configurations with a

minimum number of external components and can also be used cost

effectively in step–up applications.

These devices consist of an internal temperature compensated

reference, fixed frequency oscillator with on–chip timing components,

latching pulse width modulator for single pulse metering, high gain error

amplifier, and a high current output switch.

Protective features consist of cycle–by–cycle current limiting,

undervoltage lockout, and thermal shutdown. Also included is a low power

standby mode that reduces power supply current to 36 µA.

•Output Switch Current in Excess of 3.0 A

•Fixed Frequency Oscillator (72 kHz) with On–Chip Timing

•Provides 5.05 V Output without External Resistor Divider

•Precision 2% Reference

•0% to 95% Output Duty Cycle

•Cycle–by–Cycle Current Limiting

•Undervoltage Lockout with Hysteresis

•Internal Thermal Shutdown

•Operation from 7.5 V to 40 V

•Standby Mode Reduces Power Supply Current to 36 µA

•Economical 5–Lead TO–220 Package with Two Optional Leadforms

•Also Available in Surface Mount D2PAK Package

Simplified Block Diagram

(Step Down Application)

EA VO

ILIMIT

Vin

UVLO

5.05 V/3.0 A

Reference

Thermal

PWM

Oscillator

This device contains 143 active transistors.

Motorola, Inc. 1996 Rev 4

MC34166 MC33166

2MOTOROLA ANALOG IC DEVICE DATA

MAXIMUM RATINGS

Rating Symbol Value Unit

Power Supply Input Voltage VCC 40 V

Switch Output Voltage Range VO(switch) –1.5 to + Vin V

Voltage Feedback and Compensation Input

V oltage Range VFB, VComp –1.0 to + 7.0 V

Power Dissipation

Case 314A, 314B and 314D (TA = +25°C) PDInternally Limited W

Thermal Resistance, Junction–to–Ambient θJA 65 °C/W

Thermal Resistance, Junction–to–Case θJC 5.0 °C/W

Case 936A (D2PAK) (TA = +25°C) PDInternally Limited W

Thermal Resistance, Junction–to–Ambient θJA 70 °C/W

Thermal Resistance, Junction–to–Case θJC 5.0 °C/W

Operating Junction Temperature TJ+150 °C

Operating Ambient Temperature (Note 3)

MC34166

MC33166

TA0 to + 70

– 40 to + 85

°C

Storage Temperature Range Tstg – 65 to +150 °C

ELECTRICAL CHARACTERISTICS (VCC = 12 V, for typical values TA = +25°C, for min/max values TA is the operating ambient

temperature range that applies [Notes 2, 3], unless otherwise noted.)

Characteristic Symbol Min Typ Max Unit

OSCILLATOR

Frequency (VCC = 7.5 V to 40 V) TA = +25°C

TA = Tlow to Thigh fOSC 65

62 72

–79

81 kHz

ERROR AMPLIFIER

Voltage Feedback Input Threshold TA = +25°C

TA = Tlow to Thigh VFB(th) 4.95

4.85 5.05

–5.15

5.2 V

Line Regulation (VCC = 7.5 V to 40 V, TA = +25°C) Regline –0.03 0.078 %/V

Input Bias Current (VFB = VFB(th) + 0.15 V) IIB –0.15 1.0 µA

Power Supply Rejection Ratio (VCC = 10 V to 20 V, f = 120 Hz) PSRR 60 80 – dB

Output Voltage Swing

High State (ISource = 75 µA, VFB = 4.5 V)

Low State (ISink = 0.4 mA, VFB = 5.5 V) VOH

VOL 4.2

–4.9

1.6 –

1.9

PWM COMPARATOR

Duty Cycle

Maximum (VFB = 0 V)

Minimum (VComp = 1.9 V) DC(max)

DC(min) 92

095

0100

SWITCH OUTPUT

Output Voltage Source Saturation (VCC = 7.5 V, ISource = 3.0 A) Vsat –(VCC

–1.5) (VCC

–1.8) V

Off–State Leakage (VCC = 40 V, Pin 2 = Gnd) Isw(off) – 0 100 µA

Current Limit Threshold Ipk(switch) 3.3 4.3 6.0 A

Switching T imes (VCC = 40 V, Ipk = 3.0 A, L = 375 µH, TA = +25°C)

Output Voltage Rise Time

Output Voltage Fall Time tr

tf–

–100

50 200

100

UNDERVOLTAGE LOCKOUT

Startup Threshold (VCC Increasing, TA = +25°C) Vth(UVLO) 5.5 5.9 6.3 V

Hysteresis (VCC Decreasing, TA = +25°C) VH(UVLO) 0.6 0.9 1.2 V

TOTAL DEVICE

Power Supply Current (TA = +25°C )

Standby (VCC = 12 V, VComp < 0.15 V)

Operating (VCC = 40 V, Pin 1 = Gnd for maximum duty cycle)

ICC –

–36

31 100

55 µA

NOTES: 1.Maximum package power dissipation limits must be observed to prevent thermal shutdown activation.

2.Low duty cycle pulse techniques are used during test to maintain junction temperature as close to ambient as possible.

3.Tlow =0°C for MC34166 Thigh = + 70°C for MC34166

=–40°C for MC33166 = + 85°C for MC33166

MC34166 MC33166

MOTOROLA ANALOG IC DEVICE DATA

Figure 1. Voltage Feedback Input Threshold

versus Temperature Figure 2. Voltage Feedback Input Bias

Current versus Temperature

Figure 3. Error Amp Open Loop Gain and

Phase versus Frequency Figure 4. Error Amp Output Saturation

versus Sink Current

Figure 5. Oscillator Frequency Change

versus Temperature Figure 6. Switch Output Duty Cycle

versus Compensation Voltage

–20

AVOL, OPEN LOOP VOLT AGE GAIN (dB)

10 M10 f, FREQUENCY (Hz)

120

150

180

100 1.0 k 10 k 100 k 1.0 M

100

, EXCESS PHASE (DEGREES)

Gain

Phase

–12

–55 T

, AMBIENT TEMPERATURE (

– 25 0 25 50 75 100 125

– 8.0

– 4.0

4.0

, OSCILLATOR FREQUENCY CHANGE (%)

OSC

∆

4.85

VFB(th), VOLTAGE FEEDBACK INPUT THRESHOLD (V)

TA, AMBIENT TEMPERATURE (

4.93

5.01

5.09

5.17

5.25

– 55 – 25 0 25 50 75 100 125

VCC = 12 V

IIB, INPUT BIAS CURRENT (nA)

TA, AMBIENT TEMPERATURE (

100

– 55 – 25 0 25 50 75 100 125

Vsat, OUTPUT SATURATION VOLTAGE (V)

2.00 ISink, OUTPUT SINK CURRENT (mA)

0.4 0.8 1.2 1.6

0.4

0.8

1.2

1.6

2.0

DC, SWITCH OUTPUT DUTY CYCLE (%)

1.5 VComp, COMPENSATION VOLT AGE (V)

2.0 2.5 3.0 3.5 4.0

100

4.5

VCC = 12 V

VComp = 3.25 V

RL = 100 k

TA = +25

VFB(th) Max = 5.15 V

VFB(th) Min = 4.95 V

VFB(th) Typ = 5.05 V

VCC = 12 V

VFB = VFB(th)

VCC = 12 V

VFB = 5.5 V

TA = +25

VCC = 12 V

TA = +25

VCC = 12 V

MC34166 MC33166

4MOTOROLA ANALOG IC DEVICE DATA

Figure 7. Switch Output Source Saturation

versus Source Current Figure 8. Negative Switch Output Voltage

versus Temperature

Figure 9. Switch Output Current Limit

Threshold versus Temperature Figure 10. Standby Supply Current

versus Supply Voltage

Figure 11. Undervoltage Lockout

Threshold versus Temperature Figure 12. Operating Supply Current

versus Supply Voltage

4.5

–55 T

, AMBIENT TEMPERATURE (

– 25 0 25 50 75 100 125

5.0

5.5

6.0

6.5

, UNDERVOLTAGE LOCKOUT THRESHOLD (V)

th(UVLO)

– 2.5

ISource, SWITCH OUTPUT SOURCE CURRENT (A)

– 2.0

–1.5

–1.0

– 0.5

0 2.0 3.0 4.0 5.0 TA, AMBIENT TEMPERATURE (

– 55 – 25 0 25 50 75 100 125

– 3.0

Vsat, SWITCH OUTPUT SOURCE SATURATION (V)

–1.0

– 0.8

– 0.6

– 0.4

– 0.2

–1.2

Vsw, SWITCH OUTPUT VOLTAGE (V)

VCC = 12 V

Pin 5 = 2.0 V

Pins 1, 3 = Gnd

Pin 2 Driven Negative

Gnd

3.9

4.1

4.3

4.5

4.7

, CURRENT LIMIT THRESHOLD (A)

pk(switch)

– 55 – 25 0 25 50 75 100 125

VCC = 12 V

Pins 1, 2, 3 = Gnd

120

160

, SUPPLY CURRENT (

0VCC, SUPPLY VOLTAGE (V)

10 20 30 40

Pin 4 = VCC

Pins 1, 3, 5 = Gnd

Pin 2 Open

TA = +25

4.0

, SUPPLY CURRENT (mA)

00VCC, SUPPLY VOLTAGE (V)

10 20 30 40

Pin 4 = VCC

Pins 1, 3 = Gnd

Pins 2, 5 Open

TA = +25

TA, AMBIENT TEMPERATURE (

1.0

TA = +25

VCC

Isw = 100

Isw = 10 mA

Startup Threshold

VCC Increasing

T urn–Off Threshold

VCC Decreasing

MC34166 MC33166

MOTOROLA ANALOG IC DEVICE DATA

Figure 13. MC34166 Representative Block Diagram

CFRF

COVO

120

Error

Amp

5.05 V

Reference

Thermal

Shutdown

Oscillator S

Pulse Width

Modulator

PWM Latch

Gnd Compensation

100

Undervoltage

Lockout

Voltage

Feedback

Input

Switch

Output

Current

Sense

Vin

Cin

Input Voltage/VCC

Sink Only

Positive True Logic

Figure 14. Timing Diagram

4.1 V

Timing Capacitor CT

Compensation

2.3 V

OFF

Switch Output

MC34166 MC33166

6MOTOROLA ANALOG IC DEVICE DATA

INTRODUCTION

The MC34166, MC33166 series are monolithic power

switching regulators that are optimized for dc–to–dc converter

applications. These devices operate as fixed frequency,

voltage mode regulators containing all the active functions

required to directly implement step–down and

voltage–inverting converters with a minimum number of

external components. They can also be used cost effectively

in step–up converter applications. Potential markets include

automotive, computer , industrial, and cost sensitive consumer

products. A description of each section of the device is given

below with the representative block diagram shown in

Figure 13.

Oscillator

The oscillator frequency is internally programmed to

72 kHz by capacitor CT and a trimmed current source. The

charge to discharge ratio is controlled to yield a 95%

maximum duty cycle at the Switch Output. During the

discharge of CT, the oscillator generates an internal blanking

pulse that holds the inverting input of the AND gate high,

disabling the output switch transistor. The nominal oscillator

peak and valley thresholds are 4.1 V and 2.3 V respectively.

Pulse Width Modulator

The Pulse Width Modulator consists of a comparator with

the oscillator ramp voltage applied to the noninverting input,

while the error amplifier output is applied into the inverting

input. Output switch conduction is initiated when CT is

discharged to the oscillator valley voltage. As CT charges to

a voltage that exceeds the error amplifier output, the latch

resets, terminating output transistor conduction for the

duration of the oscillator ramp–up period. This PWM/Latch

combination prevents multiple output pulses during a given

oscillator clock cycle. Figures 6 and 14 illustrate the switch

output duty cycle versus the compensation voltage.

Current Sense

The MC34166 series utilizes cycle–by–cycle current

limiting as a means of protecting the output switch transistor

from overstress. Each on–cycle is treated as a separate

situation. Current limiting is implemented by monitoring the

output switch transistor current buildup during conduction, and

upon sensing an overcurrent condition, immediately turning off

the switch for the duration of the oscillator ramp–up period.

The collector current is converted to a voltage by an

internal trimmed resistor and compared against a reference

by the Current Sense comparator. When the current limit

threshold is reached, the comparator resets the PWM latch.

The current limit threshold is typically set at 4.3 A. Figure 9

illustrates switch output current limit threshold versus

temperature.

Error Amplifier and Reference

A high gain Error Amplifier is provided with access to the

inverting input and output. This amplifier features a typical dc

voltage gain of 80 dB, and a unity gain bandwidth of

600 kHz with 70 degrees of phase margin (Figure 3). The

noninverting input is biased to the internal 5.05 V reference

and is not pinned out. The reference has an accuracy of

±2.0% at room temperature. To provide 5.0 V at the load, the

reference is programmed 50 mV above 5.0 V to compensate

for a 1.0% voltage drop in the cable and connector from the

converter output. If the converter design requires an output

voltage greater than 5.05 V, resistor R1 must be added to

form a divider network at the feedback input as shown in

Figures 13 and 18. The equation for determining the output

voltage with the divider network is:

Vout

+ǒ

)

5.05

External loop compensation is required for converter

stability. A simple low–pass filter is formed by connecting a

resistor (R2) from the regulated output to the inverting input,

and a series resistor–capacitor (RF, CF) between Pins 1 and

5. The compensation network component values shown in

each of the applications circuits were selected to provide

stability over the tested operating conditions. The step–down

converter (Figure 18) is the easiest to compensate for

stability. The step–up (Figure 20) and voltage–inverting

(Figure 22) configurations operate as continuous conduction

flyback converters, and are more difficult to compensate. The

simplest way to optimize the compensation network is to

observe the response of the output voltage to a step load

change, while adjusting RF and CF for critical damping. The

final circuit should be verified for stability under four boundary

conditions. These conditions are minimum and maximum

input voltages, with minimum and maximum loads.

By clamping the voltage on the error amplifier output

(Pin 5) to less than 150 mV, the internal circuitry will be

placed into a low power standby mode, reducing the power

supply current to 36 µA with a 12 V supply voltage. Figure 10

illustrates the standby supply current versus supply voltage.

The Error Amplifier output has a 100 µA current source

pull–up that can be used to implement soft–start. Figure 17

shows the current source charging capacitor CSS through a

series diode. The diode disconnects CSS from the feedback

loop when the 1.0 M resistor charges it above the operating

range of Pin 5.

Switch Output

The output transistor is designed to switch a maximum of

40 V, with a minimum peak collector current of 3.3 A. When

configured for step–down or voltage–inverting applications,

as in Figures 18 and 22, the inductor will forward bias the

output rectifier when the switch turns off. Rectifiers with a

high forward voltage drop or long turn–on delay time should

not be used. If the emitter is allowed to go sufficiently

negative, collector current will flow, causing additional device

heating and reduced conversion efficiency. Figure 8 shows

that by clamping the emitter to 0.5 V, the collector current will

be in the range of 100 µA over temperature. A 1N5822 or

equivalent Schottky barrier rectifier is recommended to fulfill

these requirements.

Undervoltage Lockout

An Undervoltage Lockout comparator has been

incorporated to guarantee that the integrated circuit is fully

functional before the output stage is enabled. The internal

5.05 V reference is monitored by the comparator which

enables the output stage when VCC exceeds 5.9 V. To

prevent erratic output switching as the threshold is crossed,

0.9 V of hysteresis is provided.

MC34166 MC33166

MOTOROLA ANALOG IC DEVICE DATA

Thermal Protection

Internal Thermal Shutdown circuitry is provided to protect

the integrated circuit in the event that the maximum junction

temperature is exceeded. When activated, typically at 170°C,

the latch is forced into a ‘reset’ state, disabling the output

switch. This feature is provided to prevent catastrophic failures

from accidental device overheating. It is not intended to be

used as a substitute for proper heatsinking. The MC34166

is contained in a 5–lead TO–220 type package. The tab of the

package is common with the center pin (Pin 3) and is normally

connected to ground.

DESIGN CONSIDERATIONS

Do not attempt to construct a converter on wire–wrap

or plug–in prototype boards. Special care should be taken

to separate ground paths from signal currents and ground

paths from load currents. All high current loops should be

kept as short as possible using heavy copper runs to

minimize ringing and radiated EMI. For best operation, a tight

component layout is recommended. Capacitors CIN, CO, and

all feedback components should be placed as close to the IC

as physically possible. It is also imperative that the Schottky

diode connected to the Switch Output be located as close to

the IC as possible.

Figure 15. Low Power Standby Circuit Figure 16. Over Voltage Shutdown Circuit

Figure 17. Soft–Start Circuit

120

Error

Amp

Compensation

100

I = Standby Mode

VShutdown = VZener + 0.7

tSoft–Start

≈

35,000 Css

Css

1.0 M

Vin

120

Error

Amp

Compensation

100

120

Error

Amp

Compensation

100

+ +

MC34166 MC33166

8MOTOROLA ANALOG IC DEVICE DATA

Figure 18. Step–Down Converter

CFRF

2200

5.05 V/3.0 A

Reference

Thermal

Oscillator S

PWM UVLO

ILIMIT

Vin

12 V

Cin

330

6.8 k

68 k0.1

1N5822

190

Test Conditions Results

Line Regulation V in = 8.0 V to 36 V, IO = 3.0 A 5.0 mV = ±0.05%

Load Regulation Vin = 12 V, IO = 0.25 A to 3.0 A 2.0 mV = ±0.02%

Output Ripple Vin = 12 V, IO = 3.0 A 10 mVpp

Short Circuit Current Vin = 12 V, RL = 0.1 Ω4.3 A

Efficiency Vin = 12 V, IO = 3.0 A 82.8%

L = Coilcraft M1496–A or General Magnetics Technology GMT–0223, 42 turns of #16 AWG on

Magnetics Inc. 58350–A2 core. Heatsink = AAVID Engineering Inc. 5903B, or 5930B.

The Step–Down Converter application is shown in Figure 18. The output switch transistor Q1 interrupts the input voltage, generating a squarewave at the LCO filter

input. The filter averages the squarewaves, producing a dc output voltage that can be set to any level between Vin and Vref by controlling the percent conduction

time of Q1 to that of the total oscillator cycle time. If the converter design requires an output voltage greater than 5.05 V, resistor R1 must be added to form a divider

network at the feedback input.

ÉÉÉ

ÉÉÉÉÉ

Figure 19. Step–Down Converter Printed Circuit Board and Component Layout

(Bottom View) (Top View)

3.0

″

1.9

MC34166 STEP–DOWN

Vin

Cin

+– +–

MC34166 MC33166

MOTOROLA ANALOG IC DEVICE DATA

Figure 20. Step–Up/Down Converter

CFRF

1.5 k

1000

28 V/0.6 A

Reference

Thermal

Oscillator S

PWM UVLO

ILIMIT

Vin

12 V

Cin

330

6.8 k

4.7 k0.47

Q1D1

1N5822

*Gate resistor RG, zener diode D3, and diode D4 are required only when V in is greater than 20 V.

190

*RG

620

1N967A D2

1N5822

MTP3055EL

1N4148

Test Conditions Results

Line Regulation V in = 8.0 V to 24 V, IO = 0.6 A 23 mV = ±0.41%

Load Regulation Vin = 12 V, IO = 0.1 A to 0.6 A 3.0 mV = ±0.005%

Output Ripple Vin = 12 V, IO = 0.6 A 100 mVpp

Short Circuit Current Vin = 12 V, RL = 0.1 Ω4.0 A

Efficiency Vin = 12 V, IO = 0.6 A 82.8%

L = Coilcraft M1496–A or General Magnetics Technology GMT–0223, 42 turns of #16 AWG on

Magnetics Inc. 58350–A2 core.

Heatsink = AA VID Engineering Inc.

MC34166: 5903B, or 5930B

MTP3055EL: 5925B

Figure 20 shows that the MC34166 can be configured as a step–up/down converter with the addition of an external power MOSFET. Energy is stored in the

inductor during the on–time of transistors Q1 and Q2. During the off–time, the energy is transferred, with respect to ground, to the output filter capacitor and load.

This circuit configuration has two significant advantages over the basic step–up converter circuit. The first advantage is that output short–circuit protection is

provided by the MC34166, since Q1 is directly in series with Vin and the load. Second, the output voltage can be programmed to be less than V in. Notice that during

the off–time, the inductor forward biases diodes D1 and D2, transferring its energy with respect to ground rather than with respect to V in. When operating with V in

greater than 20 V, a gate protection network is required for the MOSFET. The network consists of components RG, D3, and D4.

ÎÎÎÎÎÎ

ÎÎÎ

(Top View)(Bottom View)

3.45

″

1.9

Figure 21. Step–Up/Down Converter Printed Circuit Board and Component Layout

MC34166 STEP–UP/DOWN

Vin

Cin

+– +–

MC34166 MC33166

10 MOTOROLA ANALOG IC DEVICE DATA

Figure 22. Voltage–Inverting Converter

CFRF

3.3 k

Reference

Thermal

Oscillator S

PWM UVLO

ILIMIT

Vin

12 V

Cin

330

2.4 k

4.7 k0.47

2200

–12 V/1.0 A

1N5822

190

0.047

Test Conditions Results

Line Regulation V in = 8.0 V to 24 V, IO = 1.0 A 3.0 mV = ±0.01%

Load Regulation Vin = 12 V, IO = 0.1 A to 1.0 A 4.0 mV = ±0.017%

Output Ripple Vin = 12 V, IO = 1.0 A 80 mVpp

Short Circuit Current Vin = 12 V, RL = 0.1 Ω3.74 A

Efficiency Vin = 12 V, IO = 1.0 A 81.2%

L = Coilcraft M1496–A or General Magnetics Technology GMT–0223, 42 turns of #16 AWG on

Magnetics Inc. 58350–A2 core. Heatsink = AAVID Engineering Inc. 5903B, or 5930B.

Two potential problems arise when designing the standard voltage–inverting converter with the MC34166. First, the Switch Output emitter is limited to –1.5 V with

respect to the ground pin and second, the Error Amplifier’s noninverting input is internally committed to the reference and is not pinned out. Both of these problems

are resolved by connecting the IC ground pin to the converter’s negative output as shown in Figure 22. This keeps the emitter of Q1 positive with respect to the

ground pin and has the effect of reversing the Error Amplifier inputs. Note that the voltage drop across R1 is equal to 5.05 V when the output is in regulation.

ÎÎÎ

ÎÎÎÎÎ

Figure 23. Voltage–Inverting Converter Printed Circuit Board and Component Layout

(Bottom View) (Top View)

3.0

″

1.9

MC34166

VOLTAGE-INVERTING

Vin

Cin

+–

MC34166 MC33166

MOTOROLA ANALOG IC DEVICE DATA

Figure 24. Triple Output Converter

VO1

5.05 V/2.0 A

Reference

Thermal

Oscillator S

PWM UVLO

ILIMIT

Vin

24 V

1000

6.8 k

68 k0.1

1N5822

1000

MUR110

VO3

–12 V/100 mA

VO2

12 V/300 mA

Tests Conditions Results

Line Regulation 5.0 V

12 V

–12 V

Vin = 15 V to 30 V, IO1 = 2.0 A, IO2 = 300 mA, IO3 = 100 mA 4.0 mV = ±0.04%

450 mV = ±1.9%

350 mV = ±1.5%

Load Regulation 5.0 V

12 V

–12 V

Vin = 24 V, IO1 = 500 mA to 2.0 A, IO2 = 300 mA, IO3 = 100 mA

Vin = 24 V, IO1 = 2.0 A, IO2 = 100 mA to 300 mA, IO3 = 100 mA

Vin = 24 V, IO1 = 2.0 A, IO2 = 300 mA, IO3 = 30 mA to 100 mA

2.0 mV = ±0.02%

420 mV = ±1.7%

310 mV = ±1.3%

Output Ripple 5.0 V

12 V

–12 V

Vin = 24 V, IO1 = 2.0 A, IO2 = 300 mA, IO3 = 100 mA 50 mVpp

25 mVpp

10 mVpp

Short Circuit Current 5.0 V

12 V

–12 V

Vin = 24 V, RL = 0.1 Ω4.3 A

1.83 A

1.47 A

Efficiency TOTAL Vin = 24 V, IO1 = 2.0 A, IO2 = 300 mA, IO3 = 100 mA 83.3%

T1 = Primary: Coilcraft M1496-A or General Magnetics Technology GMT–0223, 42 turns of #16 A WG on Magnetics Inc. 58350-A2 core.

T1 = Secondary: VO2 — 65 turns of #26 AWG

T1 = Secondary: VO3 — 96 turns of #28 AWG

Heatsink = AA VID Engineering Inc. 5903B, or 5930B.

Multiple auxiliary outputs can easily be derived by winding secondaries on the main output inductor to form a transformer . The secondaries must be connected so that

the energy is delivered to the auxiliary outputs when the Switch Output turns off. During the OFF time, the voltage across the primary winding is regulated by the feedback

loop, yielding a constant Volts/T urn ratio. The number of turns for any given secondary voltage can be calculated by the following equation:

# TURNS(SEC)

VO(SEC)

)

VF(SEC)

VO(PRI)

)

VF(PRI)

#TURNS(PRI)

Note that the 12 V winding is stacked on top of the 5.0 V output. This reduces the number of secondary turns and improves lead regulation. For best auxiliary regulation,

the auxiliary outputs should be less than 33% of the total output power.

MC34166 MC33166

12 MOTOROLA ANALOG IC DEVICE DATA

+ 36 V/0.25 A

R1MUR415

0.01

1N5822

MTP

3055E

2N3906

36 k

5.1 k

+1000

+ǒ

Ǔ)

Figure 25. Negative Input/Positive Output Regulator

0.22 470 k

Reference

Thermal

Oscillator S

PWM UVLO

ILIMIT

*Gate resistor RG, zener diode D3, and diode D4 are required only when V in is greater than 20 V.

Vin

–12 V 1000

0.002

5.05 0.7

Test Conditions Results

Line Regulation V in = –10 V to – 20 V, IO = 0.25 A 250 mV = ±0.35%

Load Regulation Vin = –12 V, IO = 0.025 A to 0.25 A 790 mV = ±1.19%

Output Ripple Vin = –12 V, IO = 0.25 A 80 mVpp

Efficiency Vin = –12 V, IO = 0.25 A 79.2%

L = Coilcraft M1496–A or ELMACO CHK1050, 42 turns of #16 A WG on Magnetics Inc. 58350–A2 core.

Heatsink = AA VID Engineering Inc. 5903B or 5930B

50 k

Faster

Brush

Motor

Figure 26. Variable Motor Speed Control with EMF Feedback Sensing

Reference

Thermal

Oscillator S

PWM

UVLO

ILIMIT Vin

18 V

1000

5.6 k

56 k0.1

1N5822

1.0 k

Test Conditions Results

Low Speed Line Regulation Vin = 12 V to 24 V 1760 RPM ±1%

High Speed Line Regulation V in = 12 V to 24 V 3260 RPM ±6%

MC34166 MC33166

MOTOROLA ANALOG IC DEVICE DATA

Figure 27. Off–Line Preconverter

1000

+ +

MC34166

Step–Down

Converter

0.001

Output 1

MBR20100CT

1000+ +

MC34166

Step–Down

Converter

0.001

Output 2

MBR20100CT

1000+ +

MC34166

Step–Down

Converter

0.001

Output 3

MBR20100CT

0.01

RFI

Filter

100

3.3

1N4003

MJE13005

220

0.047

1N4937

100k T2

1N5404

115 VAC

T1 = Core and Bobbin – Coilcraft PT3595

T1 = Primary – 104 turns #26 A WG

T1 = Base Drive – 3 turns #26 A WG

T1 = Secondaries – 16 turns #16 A WG

T1 = Total Gap – 0.002

″

T2 = Core – TDK T6 x 1.5 x 3 H5C2

T2 = 14 turns center tapped #30 A WG

T2 = Heatsink = AAVID Engineering Inc.

T2 = MC34166 and MJE13005 – 5903B

T2 = MBR20100CT – 5925B

The MC34166 can be used cost effectively in off–line applications even though it is limited to a maximum input voltage of 40 V. Figure 27 shows a simple and efficient

method for converting the AC line voltage down to 24 V. This preconverter has a total power rating of 125 W with a conversion efficiency of 90%. Transformer T1

provides output isolation from the AC line and isolation between each of the secondaries. The circuit self–oscillates at 50 kHz and is controlled by the saturation

characteristics of T2. Multiple MC34166 post regulators can be used to provide accurate independently regulated outputs for a distributed power system.

R , THERMAL RESISTANCE

JUNCTION-T O-AIR ( C/W)

1.0

1.5

2.0

2.5

3.0

3.5

010203025155.0

L, LENGTH OF COPPER (mm)

PD(max) for TA = +50

Minimum

Size Pad

2.0 oz. Copper

ÎÎÎÎ

Free Air

Mounted

Vertically

PD, MAXIMUM POWER DISSIPATION (W)

Figure 28. D2PAK Thermal Resistance and Maximum

Power Dissipation versus P.C.B. Copper Length

MC34166 MC33166

14 MOTOROLA ANALOG IC DEVICE DATA

Table 1. Design Equations

Calculation Step–Down Step–Up/Down Voltage–Inverting

ton

toff

(Notes 1, 2)

Vout

)

Vin

Vsat

Vout Vout

)

VF1

)

VF2

Vin

VsatQ1

VsatQ2 |Vout|

)

Vin

Vsat

ton

toff

fosc

ton

toff

)

ton

toff

fosc

ton

toff

)

ton

toff

fosc

ton

toff

)

Duty Cycle

(Note 3) ton fosc ton fosc ton fosc

IL avg Iout Iout

ton

toff

)

Iout

ton

toff

)

Ipk(switch) ILavg

)

Lavg

)

Lavg

)

Vsat

Vout

ton

Vin

VsatQ1

VsatQ2

ton

Vin

Vsat

ton

Vripple(pp)

8foscCo

)

(ESR)2

Ǹǒ

ton

toff

)

Ǔǒ

oscCo

)

(ESR)2

Ǹǒ

ton

toff

)

Ǔǒ

oscCo

)

(ESR)2

Vout Vref

)

Vref

)

Vref

)

NOTES: 1.Vsat – Switch Output source saturation voltage, refer to Figure 7.

2.VF – Output rectifier forward voltage drop. Typical value for 1N5822 Schottky barrier rectifier is 0.5 V.

3.Duty cycle is calculated at the minimum operating input voltage and must not exceed the guaranteed minimum DC(max) specification of 0.92.

Vout –

Iout –

∆IL –

Vripple(pp) –

Desired output voltage.

Desired output current.

Desired peak–to–peak inductor ripple current. For maximum output current especially when the duty cycle is greater than 0.5, it is suggested

that ∆IL be chosen to be less than 10% of the average inductor current IL avg. This will help prevent Ipk(switch) from reaching the guaranteed

minimum current limit threshold of 3.3 A. If the design goal is to use a minimum inductance value, let ∆IL = 2 (IL avg). This will proportionally

reduce the converter’s output current capability.

Desired peak–to–peak output ripple voltage. For best performance, the ripple voltage should be kept to less than 2% of V out. Capacitor CO

should be a low equivalent series resistance (ESR) electrolytic designed for switching regulator applications.

The following converter characteristics must be chosen:

MC34166 MC33166

MOTOROLA ANALOG IC DEVICE DATA

TH SUFFIX

PLASTIC PACKAGE

CASE 314A–03

OUTLINE DIMENSIONS

TV SUFFIX

PLASTIC PACKAGE

CASE 314B–05

J 5 PL

D 5 PL

12345

NOTES:

1. DIMENSIONING AND TOLERANCING PER ANSI

Y14.5M, 1982.

2. CONTROLLING DIMENSION: INCH.

3. DIMENSION D DOES NOT INCLUDE

INTERCONNECT BAR (DAMBAR) PROTRUSION.

DIMENSION D INCLUDING PROTRUSION SHALL

NOT EXCEED 0.043 (1.092) MAXIMUM.

SEATING

PLANE

–T

–

TP0.014 (0.356) M M

OPTIONAL

CHAMFER

DIM

AMIN MAX MIN MAX

MILLIMETERS

0.572 0.613 14.529 15.570

INCHES

B0.390 0.415 9.906 10.541

C0.170 0.180 4.318 4.572

D0.025 0.038 0.635 0.965

E0.048 0.055 1.219 1.397

F0.570 0.585 14.478 14.859

G0.067 BSC 1.702 BSC

J0.015 0.025 0.381 0.635

K0.730 0.745 18.542 18.923

L0.320 0.365 8.128 9.271

Q0.140 0.153 3.556 3.886

S0.210 0.260 5.334 6.604

U0.468 0.505 11.888 12.827

–P

–

J 5 PL

D 5 PL

12345

NOTES:

1. DIMENSIONING AND TOLERANCING PER ANSI

Y14.5M, 1982.

2. CONTROLLING DIMENSION: INCH.

3. DIMENSION D DOES NOT INCLUDE

INTERCONNECT BAR (DAMBAR) PROTRUSION.

DIMENSION D INCLUDING PROTRUSION SHALL

NOT EXCEED 0.043 (1.092) MAXIMUM.

1.702 BSC0.067 BSC

MIN MINMAX MAX

INCHES MILLIMETERS

DIM

14.529

9.906

4.318

0.635

1.219

21.590

0.381

22.860

8.128

3.556

–

11.888

–

2.286

15.570

10.541

4.572

0.965

1.397

23.749

0.635

27.940

9.271

3.886

15.748

12.827

18.669

2.794

0.572

0.390

0.170

0.025

0.048

0.850

0.015

0.900

0.320

0.140

–

0.468

–

0.090

0.613

0.415

0.180

0.038

0.055

0.935

0.025

1.100

0.365

0.153

0.620

0.505

0.735

0.110

SEATING

PLANE

–T

–

0.24 (0.610) M

–P

–

TP0.10 (0.254) M M

4.216 BSC0.166 BSC

8.128 BSC0.320 BSC

OPTIONAL

CHAMFER

Motorola reserves the right to make changes without further notice to any products herein. Motorola makes no warranty, representation or guarantee regarding

the suitability of its products for any particular purpose, nor does Motorola assume any liability arising out of the application or use of any product or circuit, and

specifically disclaims any and all liability, including without limitation consequential or incidental damages. “Typical” parameters which may be provided in Motorola

data sheets and/or specifications can and do vary in different applications and actual performance may vary over time. All operating parameters, including “Typicals”

must be validated for each customer application by customer’s technical experts. Motorola does not convey any license under its patent rights nor the rights of

others. Motorola products are not designed, intended, or authorized for use as components in systems intended for surgical implant into the body, or other

applications intended to support or sustain life, or for any other application in which the failure of the Motorola product could create a situation where personal injury

or death may occur. Should Buyer purchase or use Motorola products for any such unintended or unauthorized application, Buyer shall indemnify and hold Motorola

and its officers, employees, subsidiaries, affiliates, and distributors harmless against all claims, costs, damages, and expenses, and reasonable attorney fees

arising out of, directly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized use, even if such claim alleges that

Motorola was negligent regarding the design or manufacture of the part. Motorola and are registered trademarks of Motorola, Inc. Motorola, Inc. is an Equal

Opportunity/Af firmative Action Employer .

MC34166 MC33166

16 MOTOROLA ANALOG IC DEVICE DATA

T SUFFIX

PLASTIC PACKAGE

CASE 314D–03

OUTLINE DIMENSIONS

D2T SUFFIX

PLASTIC PACKAGE

CASE 936A–02

(D2PAK)

–Q

–

–T

–

SEATING

PLANE

NOTES:

1. DIMENSIONING AND TOLERANCING PER ANSI

Y14.5M, 1982.

2. CONTROLLING DIMENSION: INCH.

3. DIMENSION D DOES NOT INCLUDE

INTERCONNECT BAR (DAMBAR) PROTRUSION.

DIMENSION D INCLUDING PROTRUSION SHALL

NOT EXCEED 10.92 (0.043) MAXIMUM.

MIN MINMAX MAX

INCHES MILLIMETERS

DIM

14.529

9.906

4.318

0.635

1.219

2.210

0.381

25.908

8.128

3.556

2.667

13.792

15.570

10.541

4.572

0.965

1.397

2.845

0.635

27.051

9.271

3.886

2.972

14.783

0.572

0.390

0.170

0.025

0.048

0.087

0.015

1.020

0.320

0.140

0.105

0.543

0.613

0.415

0.180

0.038

0.055

0.112

0.025

1.065

0.365

0.153

0.117

0.582

D 5 PL

1.702 BSC0.067 BSC

12345

0.356 (0.014) T Q

M M

5 REF

123

0.010 (0.254) T

–T

–

MLP

TERMINAL 6

NOTES:

1 DIMENSIONING AND TOLERANCING PER ANSI

Y14.5M, 1982.

2 CONTROLLING DIMENSION: INCH.

3 TAB CONTOUR OPTIONAL WITHIN DIMENSIONS

A AND K.

4 DIMENSIONS U AND V ESTABLISH A MINIMUM

MOUNTING SURFACE FOR TERMINAL 6.

5 DIMENSIONS A AND B DO NOT INCLUDE MOLD

FLASH OR GATE PROTRUSIONS. MOLD FLASH

AND GATE PROTRUSIONS NOT TO EXCEED

0.025 (0.635) MAXIMUM.

DIM

AMIN MAX MIN MAX

MILLIMETERS

0.386 0.403 9.804 10.236

INCHES

B0.356 0.368 9.042 9.347

C0.170 0.180 4.318 4.572

D0.026 0.036 0.660 0.914

E0.045 0.055 1.143 1.397

G0.067 BSC 1.702 BSC

H0.539 0.579 13.691 14.707

K0.050 REF 1.270 REF

L0.000 0.010 0.000 0.254

M0.088 0.102 2.235 2.591

N0.018 0.026 0.457 0.660

P0.058 0.078 1.473 1.981

R5 REF

S0.116 REF 2.946 REF

U0.200 MIN 5.080 MIN

V0.250 MIN 6.350 MIN

OPTIONA

CHAMFE

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How to reach us:

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MC34166/D

◊