Data Sheet

ADP1071-1/ADP1071-2

Rev. B | Page 9 of 27

PIN CONFIGURATIONS AND FUNCTION DESCRIPTIONS

SR

16

AGND2

15

VREG2

14

VDD2

13

OVP

12

FB

11

COMP

10

SS2

9

ADP1071-1

(Not to Scale)

TOP VIEW

Figure 2. ADP1071-1 SOIC_W Pin Configuration

SR

16

AGND2

15

VREG2

14

VDD2

13

OVP

12

FB

11

COMP

10

SS2

9

ADP1071-2

(Not to Scale)

TOP VIEW

Figure 3. ADP1071-2 SOIC_W Pin Configuration

Table 9. Pin Function Descriptions, Wide-Body SOIC

Pin No.

Mnemonic

Description

ADP1071-1

ADP1071-2

1

1

GATE

Driver Output for the Main Power MOSFET on the Primary Side. GATE is a multiple function

pin. Connect a resistor from GATE to AGND1 to set up the open loop soft start time.

2

2

AGND1

Ground for the Primary Side.

3

3

VREG1

8 V Regulated Low Dropout (LDO) Output for the MOSFET Driver. Connect 1 μF or greater

from VREG1 to AGND1.

4

Not

applicable

MODE

Light Load Mode Pin. ADP1071-1 Only. This pin sets the light load mode threshold. Connect

MODE to AGND1 to enable forced continuous conduction mode (CCM), or to a high logic (2.5 V

or higher) to force an LLM operation, or to a resistor to set up an LLM threshold voltage.

Not

applicable

4

VIN

Input Voltage (ADP1071-2 Only). See the Primary Side Supply, Input Voltage, and LDO section.

Connect a 4.7 μF capacitor to this pin. The size of this capacitor can be reduced if the input

voltage to this pin is guaranteed stable. Reference this pin to AGND1.

5

5

EN

Precision Enable Input. The controller is enabled when EN is above the EN threshold voltage.

This pin also has a programmable EN hysteresis. This pin is referenced to AGND1.

6

6

CS

Input Current Sensing. This pin senses the input PWM current. Place a current sense resistor

between the source terminal of the power MOSFET and AGND1. This current sense resistor

sets up the input current limit. This pin is also used for the external slope compensator.

Connect a resistor from CS to the current sense resistor to generate a voltage ramp for the

slope compensation. Reference this pin to AGND1. Connect a 33 pF to 100 pF capacitor at this

pin to act as a resistor capacitor (RC) filter along with the slope compensation resistor in noisy

environments.

7

7

RT

Switching Period Resistor. Connect a resistor from RT to AGND1 to set the oscillator frequency.

8

8

SYNC

Frequency Synchronization. Connect an external clock to the SYNC pin to synchronize the

internal oscillator to this external clock frequency. Connect SYNC to AGND1 if this feature is

not used. It is recommended that the SYNC frequency be within 10% of the frequency set by

the RT pin.

9

9

SS2

Soft Start on the Secondary Side. Connect a capacitor from SS2 to AGND2 to set up the soft

start time on the secondary side.

10

10

COMP

Compensation Node on the Secondary Side. This pin is the output of the transconductance

11

11

FB

Feedback Node on the Secondary Side. Set up the resistive divider from the output voltage

such that the nominal voltage, when the power supply is in regulation, is 1.2 V. Reference this

pin to AGND2.

12

12

OVP

Output Overvoltage Protection. The OVP threshold is set at 1.36 V. Connect a resistive divider

from OVP to the output and AGND2.

13

13

VDD2

Input Supply on the Secondary Side. Connect VDD2 to the output voltage of the power

supply for a self driven configuration. Connect a 4.7 μF capacitor from VDD2 to AGND2. The

size of this capacitor can be reduced if the input voltage to VDD2 is guaranteed to be stable.

14

14

VREG2

5 V Regulated LDO Output for Internal Bias and Powering of the Drivers of the Synchronous

Rectifiers. Do not use VREG2 as a reference or load. Connect a 1 μF capacitor from VREG2 to

AGND2.

15

15

AGND2

Analog Ground on Secondary Side.

16

16

SR

Driver Output for Synchronous Rectifier MOSFET.