Analog Devices ADP1148AR, ADP1148AN-5, ADP1148AN-3.3, ADP1148AN, ADP1148AR-5 Datasheet

High Efficiency Synchronous

Q

R

S

V

TH1

V

IN

SENSE(–)

V

TH2

1.25V

OFF-TIME

CONTROL

100kV

13kV

B

V

IN

P-DRIVE SENSE(+) SENSE(–)

G

4 6

C

T

I

TH

SHUTDOWN

8

13

ADP1148

10mV to

150mV

C

V

FB

INT V

CC

REFERENCE

510

T

N-DRIVE

PWR
GND

14

12

ADJUSTABLE

VERSION

V

FB
9

7

S

1

Q

R

S

2

V

SLEEP

SIGNAL

GND

11

NON-OVERLAP

DRIVE

a

ADP1148, ADP1148-3.3, ADP1148-5

FEATURES
Operation From 3.5 V to 18 V Input Voltage
Ultrahigh Efficiency > 95%
Low Shutdown Current
Current Mode Operation for Excellent Line and Load

Transient Response
High Efficiency Maintained Over Wide Current Range
Logic Controlled Micropower Shutdown
Short Circuit Protection
Very Low Dropout Operation
Synchronous FET Switching for High Efficiency
Adaptive Nonoverlap Gate Drives

APPLICATIONS
Notebook and Palmtop Computers
Portable Instruments
Battery Operated Digital Devices
Industrial Power Distribution
Avionics Systems
Telecom Power Supplies
GPS Systems
Cellular Telephones

GENERAL DESCRIPTION

The ADP1148 is part of a family of synchronous step-down
switching regulator controllers featuring automatic sleep mode
to maintain high efficiencies at low output currents. These
devices drive external complementary power MOSFETs at
switching frequencies up to 250 kHz using a constant off-time
current-mode architecture.

Step-Down Switching Regulators

FUNCTIONAL BLOCK DIAGRAM

The constant off-time architecture maintains constant ripple
current in the inductor, easing the design of wide input range
converters. Current-mode operation provides excellent line and
load transient response. The operating current level is user
programmable via an external current sense resistor.

The ADP1148 incorporates automatic Power Saving Sleep
Mode operation when load currents drop below the level re­quired for continuous operation. In sleep mode, standby power
is reduced to only about 2 mW at V
both MOSFETs are turned off.

= 10 V. In shutdown,

IN

TYPICAL APPLICATIONS

VIN (5.2V TO 18V)

++

C

100mF

62mH

C1
10BQ040

IN

R

L*

SENSE

0.05V

1mF

>1.5V = SHUTDOWN

R

1kV

C
3300pF

10nF

0V = NORMAL

C

C

T

470pF

C

Figure 1. High Efficiency Step-Down Converter Figure 2. ADP1148-5 Typical Efficiency

REV. A

Information furnished by Analog Devices is believed to be accurate and
reliable. However, no responsibility is assumed by Analog Devices for its
use, nor for any infringements of patents or other rights of third parties
which may result from its use. No license is granted by implication or
otherwise under any patent or patent rights of Analog Devices.

INT V

ADP1148

SHUTDOWN

I

TH

C

T

S-GND

V

IN

CC

P-DRIVE

SENSE(+)

SENSE(–)

N-DRIVE

P-GND

P-CH
IRF7204

1000pF

N-CH
IRF7403

*COILTRONICS CTX-68-4
**KRL SL-1-C1-0R050L

**

V

OUT

5V/2A

+C

390mF

OUT

100

95

90

85

EFFICIENCY – %

80

75

FIGURE 1 CIRCUIT

70

0.02 2
LOAD CURRENT – A

VIN = 6V

VIN = 10V

0.2

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: [phone] World Wide Web Site: http://www.analog.com
Fax: [phone] © Analog Devices, Inc., 1997

ADP1148, ADP1148-3.3, ADP1148-5–SPECIFICATIONS

ELECTRICAL CHARACTERISTICS

(08C ≤ TA ≤ +708C,1 VIN = 10 V, V

Parameter Symbol Conditions

2

= 0 V, unless otherwise noted. See Figure 17.)

SHUTDOWN

Min Typ Max Units

FEEDBACK VOLTAGE

ADP1148 Only V

10

VIN = 9 V 1.21 1.25 1.29 V

FEEDBACK CURRENT

ADP1148 Only I

REGULATED OUTPUT VOLTAGE V

10

OUT

ADP1148-3.3 I
ADP1148-5 I

OUTPUT VOLTAGE LINE T

REGULATION dV

OUT

VIN = 9 V

= 700 mA 3.23 3.33 3.43 V

LOAD

= 700 mA 4.9 5.05 5.2 V

LOAD

= +25°C, VIN = 7 V to 12 V,

A

I

= 50 mA –40 +40 mV

LOAD

0.2 1.0 µA

OUTPUT VOLTAGE LOAD

REGULATION dV

ADP1148-3.3 5 mA < I

ADP1148-5 5 mA < I
SLEEP MODE OUTPUT RIPPLE dV
INPUT DC SUPPLY CURRENT

3

Normal Mode V
Sleep Mode (ADP1148-3.3) V
Sleep Mode (ADP1148-5) V
Shutdown V

OUT

I

OUT

I

Q

= 0 A 50 mV p-p

LOAD

TA = +25°C

= 4 V < VIN < 18 V 1.6 2.3 mA

IN

= 4 V < VIN < 18 V 160 250 µA

IN

= 4 V < VIN < 18 V 160 250 µA

IN
SHUTDOWN

< 2 A 40 65 mV

LOAD

< 2 A 60 100 mV

LOAD

= 2.1 V, 10 20 µA

4 V < VIN < 15 V

CURRENT SENSE THRESHOLD V

VOLTAGE

4

8–V7

ADP1148 Only V

ADP1148-3.3 V

ADP1148-5 V

V9 = V
V7 = 5 V, TA = +25°C25mV

= V

9

= 5 V 130 150 170 mV

V

7

= V

7

= V

V

7

= V

7

V7 = V

/4 + 25 mV (Forced),

OUT

/4 mV – 25 mV (Forced),

OUT

+ 100 mV (Forced) 25 mV

OUT

100 mV (Forced) 130 150 170 mV

OUT –

+ 100 mV (Forced 25 mV

OUT

– 100 mV (Forced) 130 150 170 mV

OUT

SHUTDOWN PIN THRESHOLD

ADP1148-3.3, ADP1148-5 V

SHUTDOWN PIN INPUT CURRENT I

PIN DISCHARGE CURRENT I

C

T

OFF-TIME t
DRIVER OUTPUT TRANSITION t

10

10

4

OFF

, t

R

F

TA = +25°C 0.6 0.8 2.0 V
0 V < V

SHUTDOWN

TA = +25°C, V

= V

V

7

V

OUT

, 506590 µA

OUT

= 0 V 2 10 µA

CT = 390 pF, I

< 8 V, VIN = 18 V 1.2 5 µA

in Regulation,

OUT

= 700 mA 4 5 6 µs

LOAD

CL = 3000 pF (Pins 1, 14)

TIMES VIN = 6 V, TA = +25°C 100 200 ns

NOTES

1

All limits at temperature extremes are guaranteed via correlation using standard Quality Control methods. Specifications subject to change without notice.

2

TJ is calculated from the ambient temperature TA and power dissipation PD according to the following formulas:

ADP1148AR, ADP1148AR-3.3, ADP1148AR-5: TJ = TA + (PD × 110°C/W)
ADP1148AN, ADP1148AN-3.3, ADP1148AN-5: TJ = TA + (PD × 70°C/W)

3

Dynamic supply current is higher due to the gate charge being delivered at the switching frequency. The allowable operating frequency may be limited by power
dissipation at high input voltages.

4

The ADP1148 version is tested with external feedback resistors, setting the nominal output voltage to 3.3 V.

Specifications subject to change without notice.

–2–

REV. A

ADP1148, ADP1148-3.3, ADP1148-5

ELECTRICAL CHARACTERISTICS

Parameter Symbol Conditions

(–408C ≤ TA ≤ +858C,1 VIN = 10 V, V

2

= 0 V, unless otherwise noted. See Figure 17.)

SHUTDOWN

Min Typ Max Units

FEEDBACK VOLTAGE

ADP1148 Only V

REGULATED OUTPUT VOLTAGE V

10

OUT

ADP1148-3.3 I
ADP1148-5 I

INPUT DC SUPPLY CURRENT

3

I

Q

VIN = 9 V 1.20 1.25 1.30 V
VIN = 9 V

= 700 mA 3.17 3.33 3.4 V

LOAD

= 700 mA 4.85 5.05 5.2 V

LOAD

Normal Mode VIN = 4 V < VIN < 18 V 1.6 2.6 mA
Sleep Mode (ADP1148-3) V
Sleep Mode (ADP1148-5) V
Shutdown V

= 4 V < VIN < 18 V 160 280 µA

IN

= 6 V < VIN < 18 V 160 280 µA

IN
SHUTDOWN

= 2.1 V, 10 24 µA

4 V < VIN < 12 V

CURRENT SENSE THRESHOLD

VOLTAGE

ADP1148 Only V9 = V

ADP1148-3.3 V
ADP1148-5.0 V

SHUTDOWN PIN THRESHOLD V

4

V8–V

10

7

= 5 V

V

7

= V

V

9

= 5 V

V

7

= V

7

= V

V

7

= V

7

V7 = V

/4 + 25 mV (Forced), 0 mV

OUT

/4 – 25 mV (Forced), 115 150 175 mV

OUT

+ 100 mV (Forced) 0 mV

OUT

– 100 mV (Forced) 115 150 175 mV

OUT

+ 100 mV (Forced) 0 mV

OUT

– 100 mV (Forced) 115 150 175 mV

OUT

ADP1148-3.3, ADP1148-5 0.55 0.8 2 V

OFF-TIME t

NOTES

1

All limits at temperature extremes are guaranteed via correlation using standard Quality Control method.

2

TJ is calculated from the ambient temperature TA and power dissipation PD according to the following formulas:

ADP1148AR, ADP1148AR-3, ADP1148AR-5: TJ = TA + (PD × 110°C/W)
ADP1148AN, ADP1148AN-3, ADP1148AN-5: TJ = TA + (PD × 70°C/W)

3

Dynamic supply current is higher due to the gate charge being delivered at the switching frequency. The allowable operating frequency may be limited by power
dissipation at high input voltages.

4

The ADP1148 version is tested with external feedback resistors setting the nominal output voltage to 3.3 V.

Specifications subject to change without notice.

OFF

CT = 390 pF, I

= 700 mA 4 5 6.2 µs

LOAD

ABSOLUTE MAXIMUM RATINGS

Input Supply Voltage (Pin 3) . . . . . . . . . . . . . –0.3 V to +20 V

Continuous Output Currents (Pins 1, 14) . . . . . . . . . . 50 mA

Sense Voltages (Pins 7, 8) . . . . . . . . . . . . . . . . –0.3 V to V

CC

Operating Temperature Range . . . . . . . . . . . . 0°C to +70°C

Extended Commercial Temperature Range . . –40°C to +85°C

Junction Temperature . . . . . . . . . . . . . . . . . . . . . . . . . 150°C

Storage Temperature Range . . . . . . . . . . . . –65°C to +150°C

Lead Temperature (Soldering, 10 sec) . . . . . . . . . . . . 300°C

REV. A

ORDERING GUIDE

Output Package Package

Model Voltage Description Option

ADP1148AN ADJ Plastic DIP N-14
ADP1148AR ADJ Small Outline Package SO-14
ADP1148AN-3.3 3.3 V Plastic DIP N-14
ADP1148AR-3.3 3.3 V Small Outline Package SO-14
ADP1148AN-5 5 V Plastic DIP N-14
ADP1148AR-5 5 V Small Outline Package SO-14

–3–

ADP1148, ADP1148-3.3, ADP1148-5

WARNING!

ESD SENSITIVE DEVICE

PIN FUNCTION DESCRIPTIONS

Pin # Mnemonic Function

1 P-Channel Drive High Current Gate Drive for Top P-Channel MOSFET. The voltage swing at Pin 4 is from V

ground.
2 NC No Connection.
3V
4C

5 Int V

IN
T

CC

Input Voltage.

External Capacitor CT from Pin 4 to Ground Sets the Operating Frequency. The frequency is also

dependent on the ratio V

OUT/VIN

.

Internal Supply Voltage, Nominally 3.3 V. Must be decoupled to signal ground. Do not externally load

this pin.
6I

TH

Error Amplifier Decoupling Point. The current comparator threshold increases with the Pin 7 voltage.
7 Sense– Connects to internal resistive divider that sets the output voltage in ADP1148-3.3 and ADP1148-5

versions. Pin 7 is also the (–) input for the current comparator.
8 Sense+ The (+) Input for the Current Comparator. A built-in offset between Pins 7 and 8, in conjunction with

, sets the current trip threshold.

R

SENSE

9V

FB

For the ADP1148 adjustable version, Pin 9 serves as the feedback pin from an external resistive divider

used to set the output voltage. On ADP1148-3.3 and ADP1148-5 versions, this pin is not used.
10 Shutdown Taking Pin 10 of the ADP1148, ADP1148-3.3 or ADP1148-5 high holds both MOSFETs off. Must be

at ground potential for normal operation.
11 Signal GND Small Signal Ground. Must be routed separately from other grounds to the (–) terminal of C
12 Power GND Driver Power Ground. Connects to source of N-channel MOSFET and the (–) terminal of C
13 NC No Connection.
14 N-Channel Drive High Current Drive for bottom N-channel MOSFET. The voltage swing at Pin 13 is from ground to

VIN.

IN

OUT

IN

to

.

.

PIN CONFIGURATIONS

14-Lead Plastic DIP

14-Lead Plastic SO

P-DRIVE

SENSE(–)

1
2

NC

3

V

IN

ADP1148

4

C

TOP VIEW

T

(Not to Scale)

5

INT V

CC

6

I

TH

7

NC = NO CONNECT

*FIXED OUTPUT VERSIONS = SD1

N-DRIVE

14
13

NC

12

POWER GND

11

SIGNAL GND

10

SHUTDOWN

9

V

FB

8

SENSE(+)

*

CAUTION

ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily
accumulate on the human body and test equipment and can discharge without detection. Although
the ADP1148, ADP1148-3.3, ADP1148-5 feature proprietary ESD protection circuitry, permanent
damage may occur on devices subjected to high energy electrostatic discharges. Therefore, proper
ESD precautions are recommended to avoid performance degradation or loss of functionality.

–4–

REV. A

Typical Performance Characteristics–ADP1148, ADP1148-3.3, ADP1148-5

L = 50mH
R

SENSE

= 0.02V

L = 25mH
R

SENSE

= 0.02V

L = 50mH

R

SENSE

= 0.05V

(V

IN–VOUT

) VOLTAGE – V

1000

800

0

052341

600

400

200

C

OUT

– mF

DV

OUT

– mV

V

IN

+40

+20

–60

04 166 8 10 12 14

0

–20

–40

FIGURE 1 CIRCUIT

I

LOAD

= 1A

I

LOAD

= 0.1A

V

SHUTDOWN

= 2V

INPUT VOLTAGE – V

SUPPLY CURRENT – mA

30

0

46 2081012141618

25

20

15

10

5

200

150

– mV

100

SENSE

R

50

0

0

123

MAXIMUM OUTPUT CURRENT – A

Figure 3. Selecting R
mum Output Current

100

GATE CHARGE

95

90

EFFICIENCY/LOSS – %

85

80

0.01 0.03 3.00.1 0.3 1.0

I

Q

OUTPUT CURRENT – A

SENSE

5

4

vs. Maxi-

I2R

1000

800

600

400

VIN = 7V

CAPACITANCE – pF

200

0

0 300100 200

V

SENSE

V

= 12V

IN

FREQUENCY – kHz

= V

OUT

VIN = 10V

= 5V

Figure 4. Operating Frequency vs.
Timing Capacitor Value

100

98
96
94
92
90
88
86

EFFICIENCY – %

84
82
80

0204 8 12 16

I

= 100mA

LOAD

FIGURE 1 CIRCUIT

INPUT VOLTAGE – V

I

LOAD

= 1A

Figure 5. Selecting Minimum Output
Capacitor vs. (V

IN–VOUT

) and Inductor

Figure 6. Typical Efficiency Losses

60

40

20

– mV

0

OUT

DV

–20

–40

–60

0 0.5 2.51.0 1.5 2.0

Figure 9. Load Regulation

REV. A

FIGURE 1 CIRCUIT

VIN = 6V

VIN = 12V

LOAD CURRENT – A

Figure 7. Efficiency vs. Input Voltage

1.6

1.4

1.2

1.0

0.8

0.6

0.4

SUPPLY CURRENT – mA

0.2

0.0
46 20

ACTIVE MODE

SLEEP MODE

8 1012141618

INPUT VOLTAGE – V

Figure 10. DC Supply Current

–5–

Figure 8. ADP1148-5 Output Voltage
Change vs. Input Voltage

Figure 11. Supply Current in Shutdown