ANALOG DEVICES ADP1873 Service Manual

Synchronous Current-Mode with

V

Constant On-Time, PWM Buck Controller

FEATURES

Power input voltage as low as 2.75 V to 20 V Bias supply voltage range: 2.75 V to 5.5 V Minimum output voltage: 0.6 V

0.6 V reference voltage with ±1.0% accuracy Supports all N-channel MOSFET power stages Available in 300 kHz, 600 KHz, and 1.0 MHz options No current-sense resistor required Power saving mode (PSM) for light loads (ADP1873 only) Resistor-programmable current-sense gain Thermal overload protection Short-circuit protection Precision enable input Integrated bootstrap diode for high-side drive 140 μA shutdown supply current Starts into a precharged load Small, 10-lead MSOP package

APPLICATIONS

Telecom and networking systems Mid to high end servers Set-top boxes DSP core power supplies

ADP1872/ADP1873

TYPICAL APPLICATIONS CIRCUIT

C

C2

R

C

R

TOP

V

OUT

R

BOT

C

VDD2

VDD = 2.75V

TO 5.5V

C

VDD

100

= 5.5V, VIN = 5.5V (PSM)

V

DD

95

90

85

80

75

70

65

EFFICIENCY (%)

60

55

50

45

V

DD

100 1k 10k 100k

Figure 2. ADP1872 Efficiency vs. Load Current (V

VIN

ADP1872/

ADP1873

COMP/EN

FB DRVH

GND SW

VDD DRVL

BST

PGND

Figure 1.

= 5.5V, VIN = 13.0V (PS M)

V

DD

= 5.5V, VIN = 16.5V (PSM )

TA = 25°C V

= 1.8V

OUT

f

= 300kHz

SW

WURTH INDUCTOR: 744325120, L = 1.2µH, DCR = 1.8m

INFINEON FETs: BSC042N03MS G (UPPER/ LOWER)

LOAD CURRENT (mA)

= 2.75V TO 20

IN

C

IN

C

BST

R

RES

V

= 5.5V, VIN = 5.5V

DD

OUT

Q1

L

V

OUT

+

C

OUT

Q2

LOAD

5A

= 1.8 V, 300 kHz)

08297-001

08297-002

GENERAL DESCRIPTION

The ADP1872/ADP1873 are versatile current-mode, synchronous step-down controllers that provide superior transient response, optimal stability, and current limit protection by using a constant on-time, pseudo-fixed frequency with a programmable currentsense gain, current-control scheme. In addition, these devices offer optimum performance at low duty cycles by using valley currentmode control architecture. This allows the ADP1872/ADP1873 to drive all N-channel power stages to regulate output voltages as low as 0.6 V.

The ADP1873 is the power saving mode (PSM) version of the device and is capable of pulse skipping to maintain output regulation while achieving improved system efficiency at light loads (see the Power Saving Mode (PSM) Version (ADP1873) section for more information).

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 that may result from its use. Specifications subject to change without notice. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Trademarks and registered trademarks are the property of their respective owners.

Available in three frequency options (300 kHz, 600 kHz, and

1.0 MHz, plus the PSM option), the ADP1872/ADP1873 are well suited for a wide range of applications. These ICs not only operate from a 2.75 V to 5.5 V bias supply, but can also accept a power input as high as 20 V.

In addition, an internally fixed, soft start period is included to limit input in-rush current from the input supply during startup and to provide reverse current protection during soft start for a precharged output. The low-side current-sense, current-gain scheme and integration of a boost diode, along with the PSM/forced pulsewidth modulation (PWM) option, reduce the external part count and improve efficiency.

The ADP1872/ADP1873 operate over the −40°C to +125°C junction temperature range and are available in a 10-lead MSOP.

ADP1872/ADP1873

REVISION HISTORY

3/10—Rev. 0 to Rev. A

Changes to Figure 1 .......................................................................... 1

Changes to Table 1 ............................................................................ 3

Changes to Table 2 ............................................................................ 5

Changes to Figure 59 Caption and Figure 60 Caption .............. 16

Changes to Figure 64 ...................................................................... 17

Changes to Timer Operation Section .......................................... 22

Changes to Table 7 .......................................................................... 23

Changes to Inductor Section ......................................................... 28

Changes to Table 9 .......................................................................... 31

Changes to Figure 82 ...................................................................... 32

Rev. A | Page 2 of 40

Changes to Figure 83 ...................................................................... 33

Changes to Figure 84 ...................................................................... 34

Changes to Figure 85 ...................................................................... 35

Changes to Figure 86 ...................................................................... 36

Changes to Differential Sensing Section and Figure 88 ............ 37

Changes to Figure 89 and Figure 90............................................. 38

Changes to Figure 91 ...................................................................... 39

Updated Outline Dimensions ....................................................... 40

10/09—Revision 0: Initial Version

ADP1872/ADP1873

SPECIFICATIONS

All limits at temperature extremes are guaranteed via correlation using standard statistical quality control (SQC). VDD = 5 V, BST − SW = 5 V, VIN = 13 V. The specifications are valid for T

Table 1.

Parameter Symbol Conditions Min Typ Max Unit

POWER SUPPLY CHARACTERISTICS

High Input Voltage Range VIN ADP1872ARMZ-0.3/ADP1873ARMZ-0.3 (300 kHz) 2.75 12 20 V ADP1872ARMZ-0.6/ADP1873ARMZ-0.6 (600 kHz) 2.75 12 20 V ADP1872ARMZ-1.0/ADP1873ARMZ-1.0 (1.0 MHz) 3.0 12 20 V Low Input Voltage Range VDD CIN = 1 μF to PGND, CIN = 0.22 μF to GND ADP1872ARMZ-0.3/ADP1873ARMZ-0.3 (300 kHz) 2.75 5 5.5 V ADP1872ARMZ-0.6/ADP1873ARMZ-0.6 (600 kHz) 2.75 5 5.5 V ADP1872ARMZ-1.0/ADP1873ARMZ-1.0 (1.0 MHz) 3.0 5 5.5 V Quiescent Current I Shutdown Current I

Q_DD

DD, SD

+ I

FB = 1.5 V, no switching 1.1 mA

Q_BST

+ I

COMP/EN < 285 mV 140 215 μA

BST, SD

Undervoltage Lockout UVLO Rising VDD (See Figure 34 for temperature variation) 2.65 V UVLO Hysteresis Falling VDD from operational state 190 mV

SOFT START

Soft Start Period See Figure 57 3.0 ms

ERROR AMPLIFER

FB Regulation Voltage VFB T T T

= 25°C 600 mV

J

= −40°C to +85°C 595.5 600 605.4 mV

J

= −40°C to +125°C 594.2 600 606.5 mV

J

Transconductance GM 300 515 730 μs FB Input Leakage Current I

FB = 0.6 V, COMP/EN = released 1 50 nA

FB, LEAK

CURRENT-SENSE AMPLIFIER GAIN

Programming Resistor (RES)

RES = 47 kΩ ± 1% 2.7 3 3.3 V/V

Value from DRVL to PGND RES = 22 kΩ ± 1% 5.5 6 6.5 V/V RES = none 11 12 13 V/V RES = 100 kΩ ± 1% 22 24 26 V/V

SWITCHING FREQUENCY

Typical values measured at 50% time points with 0 nF at DRVH and DRVL; maximum values are guaranteed by bench evaluation

ADP1872ARMZ-0.3/

300 kHz

ADP1873ARMZ-0.3 (300 kHz)

On-Time VIN = 5 V, V

Minimum On-Time VIN = 20 V 145 190 ns

Minimum Off-Time 84% duty cycle (maximum) 320 385 ns ADP1872ARMZ-0.6/

600 kHz

ADP1873ARMZ-0.6 (600 kHz)

On-Time VIN = 5 V, V

Minimum On-Time VIN = 20 V, V

Minimum Off-Time 65% duty cycle (maximum) 320 385 ns ADP1872ARMZ-1.0/

1.0 MHz

ADP1873ARMZ-1.0 (1.0 MHz)

On-Time VIN = 5 V, V

Minimum On-Time VIN = 20 V 60 85 ns

Minimum Off-Time 45% duty cycle (maximum) 320 385 ns

= −40°C to +125°C, unless otherwise specified.

J

1

= 2 V, TJ = 25°C 1120 1200 1280 ns

OUT

= 2 V, TJ = 25°C 500 520 580 ns

OUT

= 0.8 V 82 110 ns

OUT

= 2 V, TJ = 25°C 285 312 340 ns

OUT

Rev. A | Page 3 of 40

ADP1872/ADP1873

Parameter Symbol Conditions Min Typ Max Unit

OUTPUT DRIVER CHARACTERISTICS

High-Side Driver

Output Source Resistance I Output Sink Resistance I Rise Time2 t Fall Time2 t

BST − SW = 4.4 V, CIN = 4.3 nF (see Figure 59) 25 ns

r, DR VH

BST − SW = 4.4 V, CIN = 4.3 nF (see Figure 60) 11 ns

f, DRV H

Low-Side Driver

Output Source Resistance I Output Sink Resistance I Rise Time2 t Fall Time2 t

VDD = 5.0 V, CIN = 4.3 nF (see Figure 60) 18 ns

r, DR VL

VDD = 5.0 V, CIN = 4.3 nF (see Figure 59) 16 ns

f, DRV L

Propagation Delays

DRVL Fall to DRVH Rise2 t DRVH Fall to DRVL Rise2 t

SW Leakage Current I

BST − SW = 4.4 V (see Figure 59) 22 ns

tpdh, DRVH

BST − SW = 4.4 V (see Figure 60) 24 ns

tpdh, DRVL

BST = 25 V, SW = 20 V, VDD = 5.5 V 110 μA

SW, LEAK

Integrated Rectifier

Channel Impedance I

PRECISION ENABLE THRESHOLD

Logic High Level VIN = 2.9 V to 20 V, VDD = 2.75 V to 5.5 V 235 285 330 mV Enable Hysteresis VIN = 2.9 V to 20 V, VDD = 2.75 V to 5.5 V 35 mV

COMP VOLTAGE

COMP Clamp Low Voltage V

COMP Clamp High Voltage V COMP Zero Current Threshold V

THERMAL SHUTDOWN T

COMP (LOW )

COMP (H IGH)

COMP_ZC T

TMSD

(2.75 V ≤ VDD ≤ 5.5 V) 2.55 V

(2.75 V ≤ VDD ≤ 5.5 V) 1.15 V

Thermal Shutdown Threshold Rising temperature 155 °C Thermal Shutdown Hysteresis 15 °C Hiccup Current Limit Timing 6 ms

1

The maximum specified values are with the closed loop measured at 10% to 90% time points (see Figure and Figure 60), C

MOSFETs being Infineon BSC042N03MS G.

2

Not automatic test equipment (ATE) tested.

= 1.5 A, 100 ns, positive pulse (0 V to 5 V) 2 3.5 Ω

SOURCE

= 1.5 A, 100 ns, negative pulse (5 V to 0 V) 0.8 2 Ω

SINK

= 1.5 A, 100 ns, positive pulse (0 V to 5 V) 1.7 3 Ω

SOURCE

= 1.5 A, 100 ns, negative pulse (5 V to 0 V) 0.75 2 Ω

SINK

= 10 mA 22 Ω

SINK

From disable state, release COMP/EN pin to enable

0.47 V

device (2.75 V ≤ VDD ≤ 5.5 V)

59

= 4.3 nF and upper- and lower-side

GATE

Rev. A | Page 4 of 40

ADP1872/ADP1873

ABSOLUTE MAXIMUM RATINGS

Table 2.

Parameter Rating

VDD to GND −0.3 V to +6 V VIN to PGND −0.3 V to +28 V FB, COMP/EN to GND −0.3 V to (VDD + 0.3 V) DRVL to PGND −0.3 V to (VDD + 0.3 V) SW to PGND −0.3 V to +28 V SW to PGND −2 V pulse (20 ns) BST to SW −0.6 V to (VDD + 0.3 V) BST to PGND −0.3 V to +28 V DRVH to SW −0.3 V to VDD PGND to GND ±0.3 V Operating Junction Temperature

Range

Storage Temperature Range −65°C to +150°C Soldering Conditions JEDEC J-STD-020 Maximum Soldering Lead

Temperature (10 sec)

Stresses above those listed under Absolute Maximum Ratings may cause permanent damage to the device. This is a stress rating only; functional operation of the device at these or any other conditions above those indicated in the operational section of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.

−40°C to +125°C

300°C

Absolute maximum ratings apply individually only, not in combination. Unless otherwise specified, all other voltages are referenced to PGND.

THERMAL RESISTANCE

θJA is specified for the worst-case conditions, that is, a device soldered in a circuit board for surface-mount packages.

Table 3. Thermal Resistance

Package Type θJA Unit

θJA (10-Lead MSOP)

2-Layer Board 213.1 °C/W 4-Layer Board 171.7 °C/W

BOUNDARY CONDITION

In determining the values given in Ta b l e 2 and Ta b le 3 , natural convection was used to transfer heat to a 4-layer evaluation board.

ESD CAUTION

Rev. A | Page 5 of 40

ADP1872/ADP1873

PIN CONFIGURATION AND FUNCTION DESCRIPTIONS

VIN

1

FB

GND

VDD

2

ADP1872

3

TOP VIEW

(Not to Scale)

4

5

COMP/EN

Figure 3. Pin Configuration

Table 4. Pin Function Descriptions

Pin No. Mnemonic Description

1 VIN High Input Voltage. Connect VIN to the drain of the upper-side MOSFET. 2 COMP/EN Output of the Internal Error Amplifier/IC Enable. When this pin functions as EN, applying 0 V to this pin disables the IC. 3 FB Noninverting Input of the Internal Error Amplifier. This is the node where the feedback resistor is connected. 4 GND

Analog Ground Reference Pin of the IC. All sensitive analog components should be connected to this ground plane (see the Layout Considerations Section).

5 VDD

Bias Voltage Supply for the ADP1872/ADP1873 Controller (Includes the Output Gate Drivers). A bypass capacitor of 1 μF directly from this pin to PGND and a 0.1 μF across VDD and GND are recommended.

6 DRVL

Drive Output for the External Lower Side, N-Channel MOSFET. This pin also serves as the current-sense gain

setting pin (see Figure 68). 7 PGND Power GND. Ground for the lower side gate driver and lower side, N-channel MOSFET. 8 DRVH Drive Output for the External Upper Side, N-Channel MOSFET. 9 SW Switch Node Connection. 10 BST

Bootstrap for the Upper Side MOSFET Gate Drive Circuitry. An internal boot rectifier (diode) is connected

between VDD and BST. A capacitor from BST to SW is required. An external Schottky diode can also be

connected between VDD and BST for increased gate drive capability.

BST

10

9

SW

8

DRVH

PGND

7

DRVL

6

08297-003

Rev. A | Page 6 of 40

ADP1872/ADP1873

TYPICAL PERFORMANCE CHARACTERISTICS

100

VDD = 5.5V, VIN = 13V (PSM)

95

V

= 5.5V,

DD

V

= 16.5V ( PSM)

IN

90

85

80

VDD = 5.5V,

75

V

= 5.5V

IN

(PSM)

70

65

60

55

EFFICIENCY (%)

50

45

40

35

30

100 100k10k1k

Figure 4. Efficiency—300 kHz, V

V

= 5.5V, VIN = 5.5V

DD

= 3.6V, VIN = 5.5V

V

DD

V

= 5.5V, VIN = 13V

DD

V

= 3.6V, VIN = 13V

DD

V

= 5.5V, VIN = 16.5V

DD

V

= 3.6V, VIN = 16.5V

DD

WURTH IND: 744355147, L = 0.47µH, DCR: 0.80m INFINEON FETs: BSC042N03MS G (UPPER/LOWER) TA = 25°C

LOAD CURRENT (mA)

= 0.8 V

OUT

08297-004

100

VDD = 5.5V, VIN = 13V (PSM)

95

V

= 5.5V, VIN = 5.5V (PSM)

DD

90 85 80 75

V

= 5.5V,

DD

70

V

= 16.5V

IN

(PSM)

65 60 55 50 45

EFFICIENCY (%)

40 35 30 25 20 15

100 100k10k1k

Figure 7. Efficiency—600 kHz, V

= 5.5V, VIN = 5.5V

V

DD

V

= 3.6V, VIN = 5.5V

V

= 5.5V, VIN = 13V

DD

V

= 5.5V, VIN = 16.5V

DD

WURTH IND: 744355147, L = 0.47µH, DCR: 0.80m INFINEON FETs: BSC042N03MS G (UPPER/LOWER) TA = 25°C

DD

LOAD CURRENT (mA)

= 0.8 V

OUT

08297-007

100

VDD = 5.5V, VIN = 5.5V (PSM)

95

90

85

80

75

70

65

60

55

EFFICIENCY (%)

50

45

40

35

30

25

100 100k10k1k

Figure 5. Efficiency—300 kHz, V

100

VDD = 5.5V, VIN = 16.5V (PSM)

95

90

85

80

= 5.5V,

V

DD

V

= 16V

IN

75

(PSM)

70

65

60

55

EFFICIENCY (%)

50

45

40

35

30

100 100k10k1k

Figure 6. Efficiency—300 kHz, V

V

= 5.5V, VIN = 16.5V ( PSM)

V

DD

V

= 5.5V, VIN = 16.5V

DD

V

= 5.5V, VIN = 13V (PSM)

DD

V

= 3.6V, VIN = 3.6V

DD

V

= 5.5V, VIN = 13V

DD

V

= 3.6V, VIN = 5.5V

DD

WURTH IND: 744325120, L = 1.2µH, DCR: 1.8m INFINEON FETS: BSC042N03MS G ( UPPER/LOWER) TA = 25°C

LOAD CURRENT (mA)

OUT

VDD = 2.7V

13V

16.5V

WURTH IND: 7443551200, L = 2µH, DCR: 2.6m INFINEON FETs: BSC042N03MS G (UPPER/LOWER) TA = 25°C

LOAD CURRENT (mA)

IN

VDD = 3.6V

13V

16.5V

= 5.5V, VIN = 5.5V

DD

= 1.8 V

VDD = 5.5V

IN

= 7 V

OUT

13V

16.5V

100

VDD = 5.5V, = VIN = 5.5(PSM)

95

VDD = 5.5V, VIN = 5.5V

90

85

80

75

70

VDD = 5.5V, VIN = 16.5V

V

= 5.5V, VIN = 16.5V (PSM)

DD

65

60

55

EFFICIENCY (%)

50

45

V

DD

40

35

30

25

100 100k10k1k

08297-005

= 5.5V, VIN = 13V (PSM)

V

DD

V

= 3.6V, VIN = 5.5V

DD

= 5.5V, VIN = 13V

WURTH IND: 744325120, L = 1.2µH, DCR: 1.8m INFINEON FETS: BSC042N03MS G ( UPPER/LOWER) TA = 25°C

LOAD CURRENT (mA)

Figure 8. Efficiency—600 kHz, V

OUT

08297-008

= 1.8 V

100

95

VDD = 5.5V, V

= 13V (PSM)

IN

VDD = 3.6V,VIN = 13V

90

85

80

75

70

65

60

55

IN

EFFICIENCY (%)

50

V

VDD = 5.5V, VIN = 13V

VDD = 5.5V, VIN = 16.5V (PSM)

VDD = 3.6V, VIN = 16.5V

= 5.5V, VIN = 16.5V

DD

45

40

35

30

100 100k10k1k

08297-006

Figure 9. Efficiency—600 kHz, V

WURTH IND: 7443551200, L = 2µH, DCR: 2.6m INFINEON FETs: BSC042N03MS G (UPPER/LOWER) TA = 25°C

LOAD CURRENT (mA)

= 5 V

OUT

08297-009

Rev. A | Page 7 of 40

ADP1872/ADP1873

100

= 5.5V, VIN = 13V (PSM )

V

DD

95

90

85

80

75

= 5.5V,

V

70

DD

V

= 16.5V

IN

65

(PSM)

60

55

50

EFFICIENCY (%)

45

40

35

30

25

20

100 100k10k1k

Figure 10. Efficiency—1.0 MHz, V

V

DD

= 5.5V, VIN = 13V

V

DD

= 3.6V, VIN = 5.5V

V

DD

VDD = 5.5V, VIN = 5.5V

= 5.5V, VIN = 16.5V

V

= 5.5V,

DD

V

= 5.5V (PSM)

IN

V

= 3.6V, VIN = 3.6V

DD

WURTH IND: 744303012, L = 0.12µH, DCR: 0.33m INFINEON FETs: BSC042N03MS G (UPPER/LOWER) TA = 25°C

LOAD CURRENT (mA)

OUT

08297-010

= 0.8 V

0.8030

0.8025

0.8020

0.8015

0.8010

0.8005

0.8000

0.7995

0.7990

0.7985

OUTPUT VOLTAGE (V)

0.7980

0.7975

0.7970

0.7965

0.7960

VIN = 5.5V

+125°C +25°C –40°C

0 2000 4000 6000 8000 10,000 12,000 14, 000 16,000

VIN = 13V

+125°C +25°C –40°C

LOAD CURRENT (mA)

Figure 13. Output Voltage Accuracy—300 kHz, V

VIN = 16.5V

+125°C +25°C –40°C

= 0.8 V

OUT

08297-013

100

95

90

VDD = 5.5V, V

= 16.5V (PSM)

IN

= 5.5V, VIN = 5V (PSM )

V

DD

85

80

= 5.5V,

V

DD

75

V

= 13V

IN

(PSM)

70

65

60

55

50

EFFICIENCY (%)

45

40

35

30

25

20

100 100k10k1k

WURTH IND: 744303022, L = 0.22µH, DCR: 0.33m INFINEON FETs: BSC042N03MS G (UPPER/LOWER) TA = 25°C

Figure 11. Efficiency—1.0 MHz, V

100

VDD = 5.5V, VIN = 5V (PSM)

95

90

85

80

75

70

= 5V,

V

DD

V

= 13V

IN

65

60

55

50

EFFICIENCY (%)

45

40

35

30

25

20

100 10k1k

WURTH IND: 744325072, L = 0.72µH, DCR: 1.65m INFINEON FETs: BSC042N03MS G (UPPER/LOWER) TA = 25°C

Figure 12. Efficiency—1.0 MHz, V

= 5.5V, VIN = 16.5V

V

DD

VDD = 3.6V, VIN = 13V

V

= 3.6V, VIN = 16.5V

DD

V

= 5.5V, VIN = 13V

DD

LOAD CURRENT (mA)

= 5.5V, VIN = 16.5V (PSM)

V

DD

V

= 5V, VIN = 16.5V

DD

LOAD CURRENT (mA)

OUT

V

DD

V

IN

= 1.8 V

= 4 V

= 5.5V,

= 5V

1.821

1.816

1.811

1.806

1.801

OUTPUT VOLTAGE (V)

1.796

1.791

1.786

08297-011

VIN = 5.5V

+125°C +25°C –40°C

0 1500 3000 4500 6000 7500 9000 10,500 12,000 13,500 15,000

Figure 14. Output Voltage Accuracy—300 kHz, V

7.000

6.995

VIN = 13V

+125°C +25°C –40°C

LOAD CURRENT (mA)

VDD = 3.6V, VIN = 13V VDD = 3.6V, VIN = 16.5V

VIN = 16.5V

+125°C +25°C –40°C

OUT

08297-014

= 1.8 V

6.990

6.985

6.980

6.975

6.970

OUTPUT VOLTAGE (V)

6.965

6.960

6.955

08297-012

Figure 15. Output Voltage Accuracy—300 kHz, V

+125°C +25°C –40°C

VDD = 5.5V, VIN = 13V VDD = 5.5V, VIN = 16.5V

0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10,000

LOAD CURRENT (mA)

= 7 V

OUT

08297-015

Rev. A | Page 8 of 40

ADP1872/ADP1873

1.801

1.800

1.799

1.798

1.797

1.796

1.795

1.794

1.793

OUTPUT VOLTAGE (V)

1.792

1.791

1.790

1.789

VIN = 5.5V

+125°C +25°C –40°C

0 1500 3000 4500 6000 7500 9000 10,500 12,000 13,500 15,000

VIN = 13V

+125°C +25°C –40°C

LOAD CURRENT (mA)

VIN = 16.5V

Figure 16. Output Voltage Accuracy—600 kHz, V

+125°C +25°C –40°C

OUT

08297-016

= 1.8 V

1.810

1.809

1.808

1.807

1.806

1.805

1.804

1.803

1.802

1.801

OUTPUT VOLTAGE (V)

1.800

1.799

1.798

1.797

VIN = 5.5V

+125°C +25°C –40°C

0 1500 3000 4500 6000 7500 9000 10,500 12,000 13,500 15,000

VIN = 13V

+125°C +25°C –40°C

LOAD CURRENT (mA)

VIN = 16.5V

Figure 19. Output Voltage Accuracy—1.0 MHz, V

+125°C +25°C –40°C

OUT

= 1.8 V

08297-019

5.044

5.042

5.040

5.038

5.036

5.034

5.032

5.030

5.028

OUTPUT VOLTAGE (V)

5.026

5.024

5.022

5.020

+125°C +25°C –40°C

0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10,000

VDD = 5.5V, VIN = 13V VDD = 5.5V, VIN = 16.5V

LOAD CURRENT (mA)

Figure 17. Output Voltage Accuracy—600 kHz, V

0.807 VIN = 5.5V

0.806

0.805

0.804

0.803

0.802

0.801

OUTPUT VOLTAGE (V)

0.800

0.799

0.798

+125°C +25°C –40°C

VIN = 13V

0 2000 4000 6000 8000 10,000 12,000 14,000 16,000

LOAD CURRENT (mA)

+125°C +25°C –40°C

VIN = 16.5V

+125°C +25°C –40°C

Figure 18. Output Voltage Accuracy—1 MHz, V

OUT

= 5 V

= 0.8 V

4.050

4.045

4.040

4.035

4.030

4.025

4.020

4.015

4.010

4.005

4.000

3.995

OUTPUT VOLTAGE (V)

3.990

3.985

3.980

3.975

3.970 0 800 1600 2400 3200 4000 4800 5600 6400 7200 8000

08297-017

Figure 20. Output Voltage Accuracy—1.0 MHz, V

0.6030

0.6025

0.6020

0.6015

0.6010

0.6005

0.6000

0.5995

0.5990

FEEDBACK VOLT AGE (V)

0.5985

0.5980

0.5975 –40.0 –7. 5 122.590.057.525.0

08297-018

VIN = 13V

+125°C +25°C –40°C

LOAD CURRENT (mA)

VDD = 2.7V, VIN = 2.7V, 3.6V VDD = 3.6V, VIN = 3.6V TO 16.5V VDD = 5.5V, VIN = 5.5V, 13V, 16.5V

TEMPERATURE (° C)

VIN = 16.5V

+125°C +25°C –40°C

OUT

08297-020

= 4 V

08297-021

Figure 21. Feedback Voltage vs. Temperature

Rev. A | Page 9 of 40

ADP1872/ADP1873

335

325

315

305

295

285

275

265

FREQUENCY (kHz)

255

245

235

225

10.8 11. 0 11.2 11.4 11.6 11.8 12.0 12.2 12.4 12.6 12.8 13.0 13.2

VDD = 3.6V

+125°C +25°C –40°C

VIN (V)

NO LOADVDD = 5.5V

Figure 22. Switching Frequency vs. High Input Voltage,

300 kHz, ±10% of 12 V

08297-022

340

325

310

295

280

265

250

FREQUENCY (kHz)

235

220

205

190

0 1 6,00014,00012,00010,0008000600040002000

VIN = 5.5V VIN = 13V VIN = 16.5V

+125°C +25°C –40°C

LOAD CURRENT (mA)

Figure 25. Frequency vs. Load Current, 300 kHz, V

OUT

08297-025

= 0.8 V

650

600

550

500

FREQUENCY (kHz)

450

400

10.8 11. 0 11.2 11.4 11.6 11.8 12.0 12.2 12.4 12.6 12.8 13.0 13.2

VDD = 5.5V VDD = 3.6V

+125°C +25°C –40°C

VIN (V)

NO LOAD

Figure 23. Switching Frequency vs. High Input Voltage,

600 kHz, V

1000

950

900

850

800

750

700

FREQUENCY (kHz)

650

600

550

10.8 11. 0 11.2 11.4 11.6 11.8 12.0 12.2 12.4 12.6 12.8 13.0 13.2

VDD = 5.5V VDD = 3.6V

= 1.8 V, ±10% of 12 V

OUT

+125°C +25°C –40°C

VIN (V)

NO LOAD

Figure 24. Switching Frequency vs. High Input Voltage,

1.0 MHz, ±10% of 12 V

360

350

340

330

320

310

300

FREQUENCY (kHz)

290

280

270

260

08297-023

Figure 26. Frequency vs. Load Current, 300 kHz, V

358 354 350 346 342 338 334 330 326 322 318 314

FREQUENCY (kHz)

310 306 302 298 294 290

08297-024

Figure 27. Frequency vs. Load Current, 300 kHz, V

0 20,00016,000 18,00014,00012,00010,0008000600040002000

0 96006400 7200 8000 8800560048004000320024001600800

VIN = 5.5V VIN = 13V VIN = 16.5V

VIN = 13V VIN = 16.5V

+125°C +25°C –40°C

LOAD CURRENT (mA)

+125°C +25°C –40°C

LOAD CURRENT (mA)

OUT

= 1.8 V

= 7 V

08297-026

08297-027

Rev. A | Page 10 of 40

ADP1872/ADP1873

700 670 640 610 580 550 520 490 460 430 400 370

FREQUENCY (kHz)

340 310 280 250 220 190

0 16,00014,00012,00010,0008000600040002000

VIN = 5.5V VIN = 13V VIN = 16.5V

+125°C +25°C –40°C

LOAD CURRENT (mA)

Figure 28. Frequency vs. Load Current, 600 kHz, V

= 0.8 V

OUT

08297-028

FREQUENCY (kHz)

1300

1125

1150

1075

1000

925

850

775

700

625

550

475

400

0 16,00014,00012,00010,0008000600040002000

VIN = 5.5V VIN = 13V VIN = 16.5V

+125°C +25°C –40°C

LOAD CURRENT (mA)

Figure 31. Frequency vs. Load Current, V

= 1.0 MHz, 0.8 V

OUT

08297-031

815

795

775

755

735

715

695

675

655

635

615

FREQUENCY (kHz)

595

575

555

535

515

495

0 20,00016,000 18,00014,00012,00010,0008000600040002000

VIN = 5.5V VIN = 13V VIN = 16.5V

LOAD CURRENT (mA)

Figure 29. Frequency vs. Load Current, 600 kHz, V

0 96008800800072006400560048004000320024001600800

VIN = 13V VIN = 16.5V

705

698

691

684

677

670

663

656

649

642

FREQUENCY (kHz)

635

628

621

614

607

600

+125°C +25°C –40°C

LOAD CURRENT (mA)

Figure 30. Frequency vs. Load Current, 600 kHz, V

+125°C +25°C –40°C

= 1.8 V

OUT

=5 V

1450

1375

1300

1225

1150

1075

1000

925

FREQUENCY (kHz)

850

775

700

625

550

08297-029

Figure 32. Frequency vs. Load Current, 1.0 MHz, V

1450

1400

1350

1300

1250

1200

1150

FREQUENCY (kHz)

1100

1050

1000

08297-030

Figure 33. Frequency vs. Load Current, 1.0 MHz, V

VIN = 5.5V VIN = 13V VIN = 16.5V

MIN-OFF TIME ENCROACHMENT

+125°C +25°C –40°C

0 20,00016,000 18,00014,00012,00010,0008000600040002000

VIN = 13V +125°C VIN = 16.5V

0 8000800 1600 2400 3200 4000 4800 5600 6400 7200

LOAD CURRENT (mA)

+25°C –40°C

LOAD CURRENT (mA)

OUT

= 1.8 V

= 4 V

08297-032

08297-033

Rev. A | Page 11 of 40

ADP1872/ADP1873

UVLO (V)

2.658

2.657

2.656

2.655

2.654

2.653

2.652

2.651

2.650

2.649 –40 120100806040200–20

TEMPERATURE ( °C)

Figure 34. UVLO vs. Temperature

08297-034

680

630

580

530

480

430

380

330

MINIMUM OFF-TIME (ns)

280

230

180

–40 120100806040200–20

VDD = 2.7V VDD = 3.6V VDD = 5.5V

TEMPERATURE (° C)

Figure 37. Minimum Off-Time vs. Temperature

08297-037

100

95

90

85

80

75

70

65

60

55

MAXIMUM DUTY CYCLE (%)

50

45

40

300 400 500 600 700 800 900 1000

FREQUENCY (kHz)

VDD = 2.7V VDD = 3.6V VDD = 5.5V

Figure 35. Maximum Duty Cycle vs. Frequency

84 82 80 78 76 74 72 70 68 66 64 62 60 58 56 54 52

MAXIMUM DUTY CYCLE (%)

50 48 46 44 42 40

3.6 4. 8 6. 0 7.2 8.4 9.6 10.8 12.0 13.2 14.4 15. 6

VDD = 3.6V +125°C VDD = 5.5V

+25°C –40°C

VIN (V)

Figure 36. Maximum Duty Cycle vs. High Voltage Input (VIN)

+125°C +25°C –40°C

680

630

580

530

480

430

380

330

MINIMUM OFF-TIME (ns)

280

230

180

2.7 5.55.14.74.33.93.53.1

08297-035

VDD (V)

+125°C +25°C –40°C

08297-038

Figure 38. Minimum Off-Time vs. VDD (Low Input Voltage)

800

720

640

560

480

400

320

RECTIFIER DROP (mV)

240

160

80

08297-036

300 400 500 600 700 800 900 1000

VDD = 2.7V VDD = 3.6V VDD = 5.5V

+125°C +25°C –40°C

FREQUENCY (kHz)

08297-039

Figure 39. Internal Rectifier Drop vs. Frequency

Rev. A | Page 12 of 40

ANALOG DEVICES ADP1873 Service Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

FEATURES

APPLICATIONS

TYPICAL APPLICATIONS CIRCUIT

GENERAL DESCRIPTION

TABLE OF CONTENTS

REVISION HISTORY

SPECIFICATIONS

ABSOLUTE MAXIMUM RATINGS

THERMAL RESISTANCE

BOUNDARY CONDITION

ESD CAUTION

PIN CONFIGURATION AND FUNCTION DESCRIPTIONS

TYPICAL PERFORMANCE CHARACTERISTICS