Datasheet

ManualsBrandsMAXIM INTEGRATED ManualsPMICsPMIC - DC/DC voltage regulator Switched-capacitor voltage converter SOIC 8

_______________General Description

The MAX850–MAX853 low-noise, inverting, charge-

pump power supplies are ideal for biasing GaAsFETs in

cellular telephone transmitter amplifiers.

The MAX850–MAX852 offer both preset (-4.1V) and

adjustable (-0.5V to -9.0V) output voltages. The

MAX853 uses an external positive control voltage to set

the negative output voltage. Input voltage range for all

four devices is 4.5V to 10V. Output current is 5mA.

An internal linear regulator reduces the output voltage

ripple to 2mVp-p. With a well-filtered control voltage

CTRL

), the MAX853 achieves typical output ripple of

less than 1mVp-p. Supply current is 3mA max, and

shutdown current is less than 1µA max over temperature

(5µA max for MAX851).

________________________Applications

Cellular Phones

Negative Regulated Power Supplies

Personal Communicators, PDAs

Wireless Data Loggers

Continuously Adjustable GaAsFET Bias

LCD-Bias Contrast Control

____________________________Features

♦ Fixed -4.1V or Adjustable -0.5V to -9V Output at 5mA

♦ 4.5V to 10V Input Voltage Range

♦ 2mVp-p Output Voltage Ripple (MAX850–MAX852)

1mVp-p Output Voltage Ripple (MAX853)

♦ 100kHz Charge-Pump Switching Frequency

(MAX850/MAX851/MAX853)

♦ External Synchronizing Clock Input (MAX852)

♦ Logic-Level Shutdown Mode: 1µA Max Over

Temperature (MAX850/MAX852/MAX853)

♦ Low Cost, 8-Pin SO Package

Low-Noise, Regulated, Negative

Charge-Pump Power Supplies for GaAsFET Bias

________________________________________________________________

Maxim Integrated Products

GND

OUT

FB**

(MAX850–852)

SHDN*

(MAX850/853)

NEGOUT

C1-

C1+

MAX850

MAX851

MAX852

MAX853

TOP VIEW

* SHDN (MAX851)

OSC (MAX852)

** CONT (MAX853)

__________________Pin Configuration

MAX850

MAX851

MAX852



OUT

SHDN*

SHDN

OSC

NEGOUT

C1-

C1+

GND

= 4.5V to 10.0V

(4 CELLS)

OUT

= -4.1V

of GaAsFET)

* MAX850: SHDN

MAX851: SHDN

MAX852: OSC

__________Typical Operating Circuit

19-0238; Rev 2; 4/96

PART

MAX850ISA

MAX850ESA -40°C to +850°C

-25°C to +85°C

TEMP. RANGE PIN-PACKAGE

8 SO

______________Ordering Information

* Dice are specified at T

= +25

C only.

For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800

MAX851C/D

0°C to +70°C Dice*

MAX851ISA -25°C to +85°C 8 SO

MAX851ESA -40°C to +85°C 8 SO

MAX852C/D

MAX852ISA

MAX852ESA -40°C to +85°C

-25°C to +85°C

0°C to +70°C Dice*

8 SO

ise*

8 SO

MAX853C/D

0°C to +70°C Dice*

MAX853ISA -25°C to +85°C 8 SO

MAX853ESA -40°C to +85°C 8 SO

MAX850C/D

0°C to +70°C Dice*

MAX850–MAX853

EVALUATION KIT MANUAL

FOLLOWS DATA SHEET

Summary of content (8 pages)

PAGE 1
9-0238; Rev 2; 4/96 NUAL KIT MA ATION U EET L H A S V A E T WS DA FOLLO Low-Noise, Regulated, Negative Charge-Pump Power Supplies for GaAsFET Bias ____________________________Features ♦ Fixed -4.1V or Adjustable -0.5V to -9V Output at 5mA ♦ 4.
PAGE 2
MAX850–MAX853 Low-Noise, Regulated, Negative Charge-Pump Power Supplies for GaAsFET Bias ABSOLUTE MAXIMUM RATINGS Supply Voltage, VIN to GND ..................................-0.3V to 10.5V VNEGOUT to GND ...................................................-10.5V to 0.3V VIN to VNEGOUT .........................................................-0.3V to 21V VOUT to GND (Note 1) ........................................VNEGOUT to 0.3V SHDN or OSC (pin 4) Voltage to GND.........-0.3V to (VIN + 0.
PAGE 3
Low-Noise, Regulated, Negative Charge-Pump Power Supplies for GaAsFET Bias OUTPUT VOLTAGE vs. INPUT VOLTAGE OVER TEMPERATURE -4.14 -4.13 -4.12 -4.11 TA = +25°C -4.10 TA = -40°C -4.09 TA = +85°C -4.08 -4.11 -4.07 -4.10 -4.06 60 MAX850-TOC3 MAX850-TOC2 IOUT = 2.5mA -4.12 OUTPUT VOLTAGE (V) -4.15 OUTPUT VOLTAGE (V) -4.13 MAX850-TOC1 -4.16 MAXIMUM OUTPUT CURRENT vs. INPUT VOLTAGE MAXIMUM OUTPUT CURRENT (mA) OUTPUT VOLTAGE vs. OUTPUT CURRENT 50 40 30 20 10 4.0 6.0 8.0 7.0 8.0 9.0 10.
PAGE 4
_____________________________Typical Operating Characteristics (continued) (Circuit of Figure 2a, VIN = 6V, TA = +25°C, unless otherwise noted.) MAX850–MAX852 OUTPUT NOISE AND RIPPLE MAX853 OUTPUT NOISE AND RIPPLE VOUT 500µV/div VOUT 500µV/div 10µs/div VIN = 6.0V, VOUT = -4.1V, IOUT = 5mA, AC COUPLED 10µs/div VIN = 6.0V, VOUT = -4.
PAGE 5
Low-Noise, Regulated, Negative Charge-Pump Power Supplies for GaAsFET Bias MAX850/MAX851/MAX853 START-UP FROM SHUTDOWN MAX852 START-UP FROM SHUTDOWN VOUT 2V/div VOUT 2V/div VOSC 5V/div VSHDN 5V/div 200µs/div CIRCUIT OF FIGURE 2a, VIN = 6.0V, VOUT = -4.1V, IOUT = 5mA SHUTDOWN OCCURS WHEN 100kHz EXTERNAL CLOCK IS GATED OFF 200µs/div CIRCUIT OF FIGURE 2a, VIN = 6.0V, VOUT = -4.1V, IOUT = 5mA LINE-TRANSIENT RESPONSE LOAD-TRANSIENT RESPONSE 0.01mA IOUT VOUT 20mV/div 5mA VOUT 50mV/div 6.0V V IN 5.
PAGE 6
MAX850–MAX853 Low-Noise, Regulated, Negative Charge-Pump Power Supplies for GaAsFET Bias ______________________________________________________________Pin Description PIN NAME FUNCTION MAX850 MAX851 MAX852 MAX853 1 1 1 1 C1+ Positive terminal for C1 2 2 2 2 C1- Negative terminal for C1 3 3 3 3 NEGOUT 4 – – 4 SHDN Active-low TTL logic level Shutdown Input – 4 – – SHDN Active-high TTL logic level Shutdown Input – – 4 – OSC 5 5 5 – FB – – – 5 CONT 6 6 6 6
PAGE 7
Low-Noise, Regulated, Negative Charge-Pump Power Supplies for GaAsFET Bias VIN Setting the Output Voltage For the MAX850–MAX852, select either a fixed or an adjustable output voltage. Connect FB directly to GND to select the fixed -4.1V output (Figure 2a). To select an alternate output voltage, connect FB to the midpoint of a resistor voltage divider from OUT to GND (Figure 2b). VIN must be 1.0V above the absolute value of VOUT to allow proper regulation.
PAGE 8
MAX850–MAX853 Low-Noise, Regulated, Negative Charge-Pump Power Supplies for GaAsFET Bias sensitivity and interference. The clock must be a square wave between 40% and 60% duty cycle. The maximum clock frequency is 250kHz, and the minimum frequency is 50kHz. ___________________Chip Topography IN C1+ Layout and Grounding Good layout is important, primarily for good noise performance. 1) Mount all components as close together as possible.