Semiconductor Components Industries, LLC, 2003

September, 2003 - Rev. 10

Publication Order Number:

NCV8800/D

NCV8800 Series

Synchronous Buck Regulator

with 1.0 Amp Switch

The NCV8800 is an automotive synchronous step-down buck

regulator. This part provides an efficient step-down voltage compared
to linear regulators. The NCV8800 uses very few external components
allowing for maximum use of printed circuit board space.

Features

Output Voltage Options: 2.6 V, 3.3 V, 5.0 V, 7.5 V

3.0% Output

3.5 V Operation

AUXILIARY Hold Up Pin (for Cranking Conditions)

On-Chip Switching Power Devices (0.4

DS(ON)

)

Constant Frequency

Synchronous Operation

On-Chip Charge Pump Control Circuitry

Nonoverlap Logic

Power Up Sequencing Control Option (2.6 V and 3.3 V Only)

ENABLE Battery Voltage Capable Option

Selectable Reset Delay

Dual Pin Feedback Connection

Control Topology

Internally Fused Leads in SO-16L Package

NCV Prefix for Automotive and Other Applications Requiring Site

and Change Control

Typical Applications

Telecommunications

Mobile Multimedia

Instrumentation

Automotive Entertainment Systems

100

200

300

400

500

600

700

800

LOAD CURRENT (mA)

EFFICIENCY

(%)

Figure 1. Efficiency vs. Load Current

OUT

= 7.5 V

OUT

= 5.0 V

OUT

= 3.3 V

OUT

= 2.6 V

= 13.5 V

L =100

SO-16L

DW SUFFIX
CASE 751G

NCV8800xy

W
L

YYWW

COMP

FB2

FB1

IN2

DELAY

GND

SWITCH

RESET

ENABLE

AUXILIARY

PIN CONNECTIONS AND

MARKING DIAGRAM

= Voltage Ratings as Indicated Below:

2 = 2.6 V
3 = 3.3 V
5 = 5.0 V
7 = 7.5 V

= ENABLE Option as Indicated Below:

S = Sequenced
H = High Voltage

= Assembly Location

WL, L

= Wafer Lot

YY, Y

= Year

WW, W = Work Week

See detailed ordering and shipping information in the package
dimensions section on page 11 of this data sheet.

ORDERING INFORMATION

http://onsemi.com

NCV8800 Series

http://onsemi.com

MAXIMUM RATINGS*

Rating

Value

Unit

Supply Voltages, V

, V

IN2

-0.3 to 45

AUXILIARY

-0.3 to 8.0

ENABLE (Sequenced Option)

-0.3 to 7.0

ENABLE (High Voltage Option)

-0.3 to 8.0

RESET

-0.3 to 30

DELAY

-0.3 to 7.0

SWITCH (V

5VSENSE

= 0 V)

-1.0 to 45

Operating Junction Temperature

-40 to 150

Storage Temperature Range

-55 to 150

ESD - Human Body Model (AUXILIARY, ENABLE, RESET, DELAY, FB1, FB2, CP, SWITCH, COMP)

Human Body Model (VIN, VIN2)
Machine Model (All Pins)

2.0
1.3

200

kV
kV

Package Thermal Resistance, SO-16L

Junction-to-Case, R

Junction-to-Ambient, R

18
80

C/W

Lead Temperature Soldering:

Reflow (SMD Style Only) (Note 1)

240 Peak

(Note 2)

1. 60 second maximum above 183

2. -5

C/+0

C allowable condition.

*The maximum package power dissipation must be observed.

NCV8800 Series

http://onsemi.com

ELECTRICAL CHARACTERISTICS

(-40

125

C; Sequenced ENABLE Option: 3.5 V

16 V,

3.5 V

IN2

16 V, AUXILIARY = 6.0 V, ENABLE = 5.0 V; High Voltage ENABLE Option: 6.0 V

16 V, 6.0 V

IN2

16 V;

unless otherwise stated.)

Characteristic

Test Conditions

Min

Typ

Max

Unit

General

Quiescent Current (V

IN2

)

Sleep Mode
Operating

ENABLE = 0 V, V

= 12.6 V,

= -40

ENABLE = 0 V, V

= 12.6 V,

= 25

C, 125

ENABLE = 5.0 V, V

= 13.5 V, I

OUT

= 0

Switching Frequency

180

200

230

kHz

Switching Duty Cycle

Thermal Shutdown

Note 3

150

165

200

Feedback

Feedback Voltage Threshold, 2.6 V Option (V

)

2.522

2.6

2.678

Feedback Voltage Threshold, 3.3 V Option (V

)

3.201

3.3

3.399

Feedback Voltage Threshold, 5.0 V Option (V

)

4.850

5.0

5.150

Feedback Voltage Threshold, 7.5 V Option (V

)

7.275

7.5

7.725

RESET

Undervoltage RESET Threshold, 2.6 V Option

OUT

Increasing

OUT

Decreasing

2.44
2.40

-
-

- 0.04

V
V

Undervoltage RESET Hysteresis, 2.6 V Option

Overvoltage RESET Threshold, 2.6 V Option

OUT

Increasing

OUT

Decreasing

+ 0.04

-
-

2.80
2.76

V
V

Overvoltage RESET Hysteresis, 2.6 V Option

Undervoltage RESET Threshold, 3.3 V Option

OUT

Increasing

OUT

Decreasing

3.10
3.04

-
-

- 0.05

V
V

Undervoltage RESET Hysteresis, 3.3 V Option

Overvoltage RESET Threshold, 3.3 V Option

OUT

Increasing

OUT

Decreasing

+ 0.05

-
-

3.56
3.51

V
V

Overvoltage RESET Hysteresis, 3.3 V Option

Undervoltage RESET Threshold, 5.0 V Option

OUT

Increasing

OUT

Decreasing

4.70
4.61

-
-

- 0.075

V
V

Undervoltage RESET Hysteresis, 5.0 V Option

Overvoltage RESET Threshold, 5.0 V Option

OUT

Increasing

OUT

Decreasing

+ 0.075

-
-

5.39
5.31

V
V

Overvoltage RESET Hysteresis, 5.0 V Option

Undervoltage RESET Threshold, 7.5 V Option

OUT

Increasing

OUT

Decreasing

7.05
6.92

-
-

- 0.115

V
V

Undervoltage RESET Hysteresis, 7.5 V Option

115

Overvoltage RESET Threshold, 7.5 V Option

OUT

Increasing

OUT

Decreasing

+ 0.115

-
-

8.08
7.96

V
V

Overvoltage RESET Hysteresis, 7.5 V Option

115

3. Guaranteed By Design.

NCV8800 Series

http://onsemi.com

ELECTRICAL CHARACTERISTICS (continued)

(-40

125

C; Sequenced ENABLE Option: 3.5 V

16 V,

3.5 V

IN2

16 V, AUXILIARY = 6.0 V, ENABLE = 5.0 V; High Voltage ENABLE Option: 6.0 V

16 V, 6.0 V

IN2

16 V;

unless otherwise stated.)

Characteristic

Test Conditions

Min

Typ

Max

Unit

RESET

RESET Leakage Current

RESET = 5.25 V

RESET Output Low Voltage

OUT

= 1.6 mA

0.4

RESET Delay

DELAY Connected to FB1, FB2
DELAY = 0 V

28.70
14.35

32.60
16.30

36.66
18.33

ms
ms

ENABLE

ENABLE Threshold

Increasing
Decreasing

1.1
1.0

1.9
1.6

2.3
2.2

V
V

ENABLE Hysteresis

100

250

550

ENABLE Input Resistance

ENABLE = 5.25 V, V

IN2

= 13.5 V

100

200

DELAY

DELAY Input Current

DELAY = 5.15 V

4.0

SWITCH

SWITCH ON Resistance

SWITCH

= 0.5 A, T

= -40

C, 25

SWITCH

= 0.5 A, T

= 125

-
-

0.40
0.55

0.60
0.75

Current Limit

1.0

1.6

2.5

Error Amplifier

Error Amplifier Transconductance

2.6 V Option

3.3 V Option

5.0 V Option

7.5 V Option

2.58 V

FB1

2.62 V

2.58 V

FB2

2.62 V

3.275 V

FB1

3.325 V

3.275 V

FB2

3.325 V

4.962 V

FB1

5.038 V

4.962 V

FB2

5.038 V

7.442 V

FB1

7.558 V

7.442 V

FB2

7.558 V

0.55

0.43

0.28

0.19

2.10

1.65

1.09

0.73

1/m

Error Amplifier Bandwidth

Note 4

1.0

MHz

Output Tracking (Sequencing)

Feedback to ENABLE Tracking Voltage, 2.6 V Option

Feedback to ENABLE Tracking Voltage, 3.3 V Option

4. Guaranteed By Design.

NCV8800 Series

http://onsemi.com

PACKAGE PIN DESCRIPTION

PACKAGE LEAD #

LEAD SYMBOL

FUNCTION

AUXILIARY

Alternate path for voltage input to the IC.

ENABLE

Sense for powerup. This pin must be high before SWITCH turns on.

RESET

CMOS compatible open drain output lead. RESET goes low whenever FB1 or FB2 is
below the RESET low threshold, or above the RESET high threshold.

4, 5, 12, 13

GND

Ground.

DELAY

RESET delay control. Time is doubled when pin moved to FB1 or FB2 from 0 V.

FB1

Voltage feedback to error amplifier. Shorted with FB2.

FB2

Voltage feedback to error amplifier. Shorted with FB1.

COMP

Loop compensation node for error amplifier. (1.0 k

and 0.1

F to ground).

No connection.

IN2

Supply input voltage for internal bias circuitry.

SWITCH

Drive for external inductor.

Node for charge pump bootstrap capacitor.

Supply input voltage for output drivers.

NCV8800 Series

http://onsemi.com

CIRCUIT DESCRIPTION

ENABLE

The NCV8800 remains in sleep mode drawing less than

A of quiescent current until the ENABLE pin is brought

high powering up the device. There are two options
available for the ENABLE feature.

Option 1 (Sequenced). The output voltage tracks the
ENABLE pin with a maximum delta voltage between
them (reference the Output Tracking specs in the
Electrical Characteristics). This allows the device to be
used with microprocessors requiring dual supply
voltages. One voltage is typically needed to power the
core of the microprocessor, and another high voltage is
needed to power the microprocessor I/O.

Option 2 (High Voltage). This option removes the
sequencing feature above, and allows the device to be
controlled up to the battery voltage on the ENABLE
pin with an external resistor (10 k). See Figure 5.

Figure 5. Switched Battery Application

ENABLE

BAT

10 k

AUXILIARY

The AUXILIARY pin provides an alternate path for the IC

to maintain operation. The AUXILIARY pin is diode OR'd
with the V

pin to the control circuitry (the DMOS output

drivers are not included). If the voltage (V

) from the

battery dips as low as 3.5 V during a crank condition, the
NCV8800 will maintain operation through a 6.0 V(min)
connection on the AUXILIARY pin. Using this feature is
optional. This pin should be grounded when not in use.

Normal supply voltage input. An external diode must be

provided to afford reverse battery protection.

SWITCH

DMOS output drivers with 0.75

max push/pull

capability. Non-overlap logic is provided to guarantee shoot
through current is minimized.

RESET

The RESET is an open drain output which goes low when

the feedback voltage on FB1 and FB2 goes below the
undervoltage RESET threshold. The output also goes low
when the voltage on FB1 and FB2 exceeds the overvoltage
RESET threshold. The RESET output is an open drain
output capable of sinking 1.6 mA.

FB1 and FB2

FB1 and FB2 are the feedback pins to the error amplifier,

which control the output SWITCH as needed to the
regulated output. They are internally wire bonded to the
same electrical connection providing double protection for
an open circuit which would cause the buck regulator to rise
above its desired output reaching the voltage on V

. These

pins also provide the feedback path for the RESET function.

DELAY

There are two options for the delay time for the RESET to go

low. Connecting the pin to GND will provide a minimum of 14
ms. Connecting the pin to FB1 and FB2 will provide a
minimum of 28 ms. Absolute max voltage on the DELAY
pin is 7.0 V. Use a resistor divider to run off higher voltages.
The 7.5 V option will require this divider (see Figure 6).

Figure 6.

DELAY
(7.0 V max)

OUT

COMP

The COMP pin provides access to the error amplifiers

output. Switching power supplies work as feedback control
systems, and require compensation for stability. A 1.0 k
resistor and 0.1

F capacitor work well in the application in

Figure 2.

The on-chip DMOS drivers require the gates of the

devices to be pulled above their drain voltage. An external
capacitor located between the SWITCH output, and the CP
pin provides the charge pump action to drive the gate of the
high-side driver high enough to turn the device on.

NCV8800 Series

http://onsemi.com

APPLICATIONS INFORMATION

OUT

NCV8800

Switch

FB2

Power Up/Down

Sequence and

ENABLE

-
+

21.4 k

Error Amp

1.20 V

FB1

R1*

Figure 7.

*The value of R1

is dependent
on the output
voltage option
and is between
25 k and 200 k.

Increasing the Output Voltage

Adjustments to the output voltage can be made with an

external resistor (R

). The increase in output voltage will

typically be 56

. Caution and consideration must

be given to the tracking feature and temperature coefficient
and matching of internal and external resistors. Output
tracking always follows the Feedback pins (FB1 and FB2).
The typical temperature coefficient for R1 and R2 is
+4600 ppm/

THEORY OF OPERATION

Control Method

The V

method of control uses a ramp signal that is

generated by the ESR of the output capacitors. This ramp is
proportional to the AC current through the main inductor
and is offset by the value of the DC output voltage. This
control scheme inherently compensates for variations in
either line or load conditions, since the ramp signal is
generated from the output voltage itself. This control
scheme differs from traditional techniques such as voltage
mode, which generates an artificial ramp, and current mode,
which generates a ramp from inductor current.

Ramp Signal

Error Signal

Error Amplifier

COMP

GATE(L)

GATE(H)

Output
Voltage
Feedback

PWM Comparator

Figure 8. V

Control Block Diagram

Reference

Voltage

The V

control method is illustrated in Figure 8. The output

voltage is used to generate both the error signal and the ramp
signal. Since the ramp signal is simply the output voltage, it
is affected by any change in the output regardless of the origin
of the change. The ramp signal also contains the DC portion
of the output voltage, which allows the control circuit to drive
the main switch to 0% or 100% duty cycle as required.

A change in line voltage changes the current ramp in the

inductor, affecting the ramp signal, which causes the V

control scheme to compensate the duty cycle. Since the
change in the inductor current modifies the ramp signal, as
in current mode control, the V

control scheme has the same

advantages in line transient response.

A change in load current will have an effect on the output

voltage, altering the ramp signal. A load step immediately
changes the state of the comparator output, which controls
the main switch. Load transient response is determined only
by the comparator response time and the transition speed of
the main switch. The reaction time to an output load step has
no relation to the crossover frequency of the error signal
loop, as in traditional control methods.

The error signal loop can have a low crossover frequency,

since transient response is handled by the ramp signal loop.
The main purpose of this "slow" feedback loop is to provide
DC accuracy. Noise immunity is significantly improved,
since the error amplifier bandwidth can be rolled off at a low
frequency. Enhanced noise immunity improves remote
sensing of the output voltage, since the noise associated with
long feedback traces can be effectively filtered.

Line and load regulations are drastically improved

because there are two independent voltage loops. A voltage
mode controller relies on a change in the error signal to
compensate for a derivation in either line or load voltage.
This change in the error signal causes the output voltage to
change corresponding to the gain of the error amplifier,
which is normally specified as line and load regulation. A
current mode controller maintains fixed error signal under
deviation in the line voltage, since the slope of the ramp
signal changes, but still relies on a change in the error signal
for a deviation in load. The V

method of control maintains

a fixed error signal for both line and load variations, since
both line and load affect the ramp signal.

Constant Frequency Operation

During normal operation, the oscillator generates a 200 kHz,

90% duty cycle waveform. The rising edge of this waveform
determines the beginning of each switching cycle, at which
point the high-side switch will be turned on. The high-side
switch will be turned off when the ramp signal intersects the
output of the error amplifier (COMP pin voltage).
Therefore,

the switch duty cycle can be modified to regulate

the output voltage to the desired value as line and load
conditions change.

NCV8800 Series

http://onsemi.com

The major advantage of constant frequency operation is

that the component selections, especially the magnetic
component design, become very easy. Oscillator frequency
is fixed at 200 kHz.

Start-Up

After the NCV8800 is powered up, the error amplifier will

begin linearly charging the COMP pin capacitor. The COMP
capacitance and the source current of the error amplifier
determine the slew rate of COMP voltage. The output of the
error amplifier is connected internally to the inverting input
of the PWM comparator and it is compared with the divided
down output voltage FB1/FB2 at the non-inverting input of
the PWM comparator. At the beginning of each switching
cycle, the oscillator output will set the PWM latch. This
causes the high-side switch to turn on and the regulator
output voltage to ramp up.

When the divided down output voltage achieves a level set

by the COMP voltage, the high-side switch will be turned
off. The V

control loop will adjust the high-side switch

duty cycle as required to ensure the regulator output voltage
tracks the COMP voltage. Since the COMP voltage
increases gradually, Soft Start can be achieved.

Overcurrent Protection

The output switch is protected on both the high side and

low side. Current limit is set at 1.0 A (min).

Figure 9. 16 Lead SOW (4 Leads Fused),

JA as

a Function of the Pad Copper Area (2 oz. Cu.

Thickness), Board Material = 0.0625

G-10/R-4

100

Thermal

Resistance,

Junction to Ambient, R

, (

C/W)

Copper Area (inch

)

0.5

1.0

1.5

2.0

3.0

2.5

Heat Sinks

A heat sink effectively increases the surface area of the

package to improve the flow of heat away from the IC and
into the surrounding air.

Each material in the heat flow path between the IC and the

outside environment will have a thermal resistance. Like
series electrical resistances, these resistances are summed to
determine the value of R

qJA

)

(3)

where:

qJC

= the junction-to-case thermal resistance,

qCS

= the case-to-heatsink thermal resistance, and

qSA

= the heatsink-to-ambient thermal resistance.

qJC

appears in the package section of the data sheet. Like

qJA

, it too is a function of package type. R

qCS

and R

qSA

are

functions of the package type, heatsink and the interface
between them. These values appear in heat sink data sheets
of heat sink manufacturers.

NCV8800 Series

http://onsemi.com

PACKAGE DIMENSIONS

SO-16L

DW SUFFIX

CASE 751G-03

ISSUE B

14X

16X

SEATING

PLANE

0.25

X 45

0.25

NOTES:

1. DIMENSIONS ARE IN MILLIMETERS.

2. INTERPRET DIMENSIONS AND TOLERANCES

PER ASME Y14.5M, 1994.

3. DIMENSIONS D AND E DO NOT INLCUDE MOLD

PROTRUSION.

4. MAXIMUM MOLD PROTRUSION 0.15 PER SIDE.

5. DIMENSION B DOES NOT INCLUDE DAMBAR

PROTRUSION. ALLOWABLE DAMBAR

PROTRUSION SHALL BE 0.13 TOTAL IN EXCESS

OF THE B DIMENSION AT MAXIMUM MATERIAL

CONDITION.

DIM

MIN

MAX

MILLIMETERS

2.35

2.65

0.10

0.25

0.35

0.49

0.23

0.32

10.15

10.45

7.40

7.60

1.27 BSC

10.05

10.55

0.25

0.75

0.50

0.90

ON Semiconductor and are registered trademarks of Semiconductor Components Industries, LLC (SCILLC). SCILLC reserves the right to make
changes without further notice to any products herein. SCILLC makes no warranty, representation or guarantee regarding the suitability of its products for any
particular purpose, nor does SCILLC 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 special, consequential or incidental damages. "Typical" parameters which may be provided in SCILLC 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. SCILLC does not convey any license under its patent rights nor the rights of others.
SCILLC 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 SCILLC product could create a situation where personal injury or death
may occur. Should Buyer purchase or use SCILLC products for any such unintended or unauthorized application, Buyer shall indemnify and hold SCILLC
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
SCILLC was negligent regarding the design or manufacture of the part. SCILLC is an Equal Opportunity/Affirmative Action Employer.

PUBLICATION ORDERING INFORMATION

JAPAN: ON Semiconductor, Japan Customer Focus Center

2-9-1 Kamimeguro, Meguro-ku, Tokyo, Japan 153-0051
Phone: 81-3-5773-3850

ON Semiconductor Website: http://onsemi.com

For additional information, please contact your local
Sales Representative.

NCV8800/D

is a trademark of Switch Power, Inc.

Literature Fulfillment:

Literature Distribution Center for ON Semiconductor
P.O. Box 5163, Denver, Colorado 80217 USA
Phone: 303-675-2175 or 800-344-3860 Toll Free USA/Canada
Fax: 303-675-2176 or 800-344-3867 Toll Free USA/Canada
Email: orderlit@onsemi.com

N. American Technical Support: 800-282-9855 Toll Free USA/Canada

Ð­Ð»ÐµÐºÑ‚Ñ€Ð¾Ð½Ð½Ñ‹Ð¹ ÐºÐ¾Ð¼Ð¿Ð¾Ð½ÐµÐ½Ñ‚: NCV8800SDW26R2

ÐÐ»ÐµÐºÑ‚Ñ€Ð¾Ð½Ð½Ñ‹Ð¹ ÐºÐ¾Ð¼Ð¿Ð¾Ð½ÐµÐ½Ñ‚: NCV8800SDW26R2